1DRBDSETUP(8) System Administration DRBDSETUP(8)
2
6 drbdsetup - Setup tool for DRBD
7
9 drbdsetup new-resource resource [--cpu-mask {val}]
10 [--on-no-data-accessible {io-error | suspend-io}]
11 drbdsetup new-minor resource minor volume
13 drbdsetup del-resource resource
15 drbdsetup del-minor minor
17 drbdsetup attach minor lower_dev meta_data_dev meta_data_index
19 [--size {val}] [--max-bio-bvecs {val}]
20 [--on-io-error {pass_on | call-local-io-error | detach}]
21 [--fencing {dont-care | resource-only | resource-and-stonith}]
22 [--disk-barrier] [--disk-flushes] [--disk-drain]
23 [--md-flushes] [--resync-rate {val}] [--resync-after {val}]
24 [--al-extents {val}] [--al-updates]
25 [--discard-zeroes-if-aligned] [--disable-write-same]
26 [--c-plan-ahead {val}] [--c-delay-target {val}]
27 [--c-fill-target {val}] [--c-max-rate {val}]
28 [--c-min-rate {val}] [--disk-timeout {val}]
29 [--read-balancing {prefer-local | prefer-remote | round-robin | least-pending | when-congested-remote | 32K-striping | 64K-striping | 128K-striping | 256K-striping | 512K-striping | 1M-striping}]
30 [--rs-discard-granularity {val}]
31 drbdsetup connect resource local_addr remote_addr [--tentative]
33 [--discard-my-data] [--protocol {A | B | C}]
34 [--timeout {val}] [--max-epoch-size {val}]
35 [--max-buffers {val}] [--unplug-watermark {val}]
36 [--connect-int {val}] [--ping-int {val}]
37 [--sndbuf-size {val}] [--rcvbuf-size {val}]
38 [--ko-count {val}] [--allow-two-primaries]
39 [--cram-hmac-alg {val}] [--shared-secret {val}]
40 [--after-sb-0pri {disconnect | discard-younger-primary | discard-older-primary | discard-zero-changes | discard-least-changes | discard-local | discard-remote}]
41 [--after-sb-1pri {disconnect | consensus | discard-secondary | call-pri-lost-after-sb | violently-as0p}]
42 [--after-sb-2pri {disconnect | call-pri-lost-after-sb | violently-as0p}]
43 [--always-asbp]
44 [--rr-conflict {disconnect | call-pri-lost | violently}]
45 [--ping-timeout {val}] [--data-integrity-alg {val}]
46 [--tcp-cork]
47 [--on-congestion {block | pull-ahead | disconnect}]
48 [--congestion-fill {val}] [--congestion-extents {val}]
49 [--csums-alg {val}] [--csums-after-crash-only]
50 [--verify-alg {val}] [--use-rle]
51 [--socket-check-timeout {val}]
52 drbdsetup disk-options minor
54 [--on-io-error {pass_on | call-local-io-error | detach}]
55 [--fencing {dont-care | resource-only | resource-and-stonith}]
56 [--disk-barrier] [--disk-flushes] [--disk-drain]
57 [--md-flushes] [--resync-rate {val}] [--resync-after {val}]
58 [--al-extents {val}] [--al-updates]
59 [--discard-zeroes-if-aligned] [--disable-write-same]
60 [--c-plan-ahead {val}] [--c-delay-target {val}]
61 [--c-fill-target {val}] [--c-max-rate {val}]
62 [--c-min-rate {val}] [--disk-timeout {val}]
63 [--read-balancing {prefer-local | prefer-remote | round-robin | least-pending | when-congested-remote | 32K-striping | 64K-striping | 128K-striping | 256K-striping | 512K-striping | 1M-striping}]
64 [--rs-discard-granularity {val}]
65 drbdsetup net-options local_addr remote_addr [--protocol {A | B | C}]
67 [--timeout {val}] [--max-epoch-size {val}]
68 [--max-buffers {val}] [--unplug-watermark {val}]
69 [--connect-int {val}] [--ping-int {val}]
70 [--sndbuf-size {val}] [--rcvbuf-size {val}]
71 [--ko-count {val}] [--allow-two-primaries]
72 [--cram-hmac-alg {val}] [--shared-secret {val}]
73 [--after-sb-0pri {disconnect | discard-younger-primary | discard-older-primary | discard-zero-changes | discard-least-changes | discard-local | discard-remote}]
74 [--after-sb-1pri {disconnect | consensus | discard-secondary | call-pri-lost-after-sb | violently-as0p}]
75 [--after-sb-2pri {disconnect | call-pri-lost-after-sb | violently-as0p}]
76 [--always-asbp]
77 [--rr-conflict {disconnect | call-pri-lost | violently}]
78 [--ping-timeout {val}] [--data-integrity-alg {val}]
79 [--tcp-cork]
80 [--on-congestion {block | pull-ahead | disconnect}]
81 [--congestion-fill {val}] [--congestion-extents {val}]
82 [--csums-alg {val}] [--csums-after-crash-only]
83 [--verify-alg {val}] [--use-rle]
84 [--socket-check-timeout {val}]
85 drbdsetup resource-options resource [--cpu-mask {val}]
87 [--on-no-data-accessible {io-error | suspend-io}]
88 drbdsetup disconnect local_addr remote_addr [--force]
90 drbdsetup detach minor [--force]
92 drbdsetup primary minor [--force]
94 drbdsetup secondary minor
96 drbdsetup down resource
98 drbdsetup verify minor [--start {val}] [--stop {val}]
100 drbdsetup invalidate minor
102 drbdsetup invalidate-remote minor
104 drbdsetup wait-connect minor [--wfc-timeout {val}]
106 [--degr-wfc-timeout {val}] [--outdated-wfc-timeout {val}]
107 [--wait-after-sb {val}]
108 drbdsetup wait-sync minor [--wfc-timeout {val}]
110 [--degr-wfc-timeout {val}] [--outdated-wfc-timeout {val}]
111 [--wait-after-sb {val}]
112 drbdsetup role minor
114 drbdsetup cstate minor
116 drbdsetup dstate minor
118 drbdsetup resize minor [--size {val}] [--assume-peer-has-space]
120 [--assume-clean] [--al-stripes {val}]
121 [--al-stripe-size-kB {val}]
122 drbdsetup check-resize minor
124 drbdsetup pause-sync minor
126 drbdsetup resume-sync minor
128 drbdsetup outdate minor
130 drbdsetup show-gi minor
132 drbdsetup get-gi minor
134 drbdsetup show {resource | minor | all}
136 drbdsetup suspend-io minor
138 drbdsetup resume-io minor
140 drbdsetup status {resource | all} [--color {val}]
142 drbdsetup events2 {resource | all}
144 drbdsetup events {resource | minor | all}
146 drbdsetup new-current-uuid minor [--clear-bitmap]
148
150 drbdsetup is used to associate DRBD devices with their backing block
151 devices, to set up DRBD device pairs to mirror their backing block
152 devices, and to inspect the configuration of running DRBD devices.
153
155 drbdsetup is a low level tool of the DRBD program suite. It is used by
156 the data disk and drbd scripts to communicate with the device driver.
157
159 Each drbdsetup sub-command might require arguments and bring its own
160 set of options. All values have default units which might be overruled
161 by K, M or G. These units are defined in the usual way (e.g. K = 2^10 =
162 1024).
163 Common options
165 All drbdsetup sub-commands accept these two options
166 --create-device
168 In case the specified DRBD device (minor number) does not exist
169 yet, create it implicitly.
170 new-resource
172 Resources are the primary objects of any DRBD configuration. A resource
173 must be created with the new-resource command before any volumes or
174 minor devices can be created. Connections are referenced by name.
175 new-minor
177 A minor is used as a synonym for replicated block device. It is
178 represented in the /dev/ directory by a block device. It is the
179 application's interface to the DRBD-replicated block devices. These
180 block devices get addressed by their minor numbers on the drbdsetup
181 commandline.
182 A pair of replicated block devices may have different minor numbers on
184 the two machines. They are associated by a common volume-number. Volume
185 numbers are local to each connection. Minor numbers are global on one
186 node.
187 del-resource
189 Destroys a resource object. This is only possible if the resource has
190 no volumes.
191 del-minor
193 Minors can only be destroyed if its disk is detached.
194 attach, disk-options
196 Attach associates device with lower_device to store its data blocks on.
197 The -d (or --disk-size) should only be used if you wish not to use as
198 much as possible from the backing block devices. If you do not use -d,
199 the device is only ready for use as soon as it was connected to its
200 peer once. (See the net command.)
201 With the disk-options command it is possible to change the options of a
203 minor while it is attached.
204 --disk-size size
206 You can override DRBD's size determination method with this option.
207 If you need to use the device before it was ever connected to its
208 peer, use this option to pass the size of the DRBD device to the
209 driver. Default unit is sectors (1s = 512 bytes).
210 If you use the size parameter in drbd.conf, we strongly recommend
212 to add an explicit unit postfix. drbdadm and drbdsetup used to have
213 mismatching default units.
214 --on-io-error err_handler
216 If the driver of the lower_device reports an error to DRBD, DRBD
217 will mark the disk as inconsistent, call a helper program, or
218 detach the device from its backing storage and perform all further
219 IO by requesting it from the peer. The valid err_handlers are:
220 pass_on, call-local-io-error and detach.
221 --fencing fencing_policy
223 Under fencing we understand preventive measures to avoid situations
224 where both nodes are primary and disconnected (AKA split brain).
225 Valid fencing policies are:
227 dont-care
229 This is the default policy. No fencing actions are done.
230 resource-only
232 If a node becomes a disconnected primary, it tries to outdate
233 the peer's disk. This is done by calling the fence-peer
234 handler. The handler is supposed to reach the other node over
235 alternative communication paths and call 'drbdadm outdate res'
236 there.
237 resource-and-stonith
239 If a node becomes a disconnected primary, it freezes all its IO
240 operations and calls its fence-peer handler. The fence-peer
241 handler is supposed to reach the peer over alternative
242 communication paths and call 'drbdadm outdate res' there. In
243 case it cannot reach the peer, it should stonith the peer. IO
244 is resumed as soon as the situation is resolved. In case your
245 handler fails, you can resume IO with the resume-io command.
246 --disk-barrier,
248 --disk-flushes,
249 --disk-drain
250 DRBD has four implementations to express write-after-write
251 dependencies to its backing storage device. DRBD will use the first
252 method that is supported by the backing storage device and that is
253 not disabled. By default the flush method is used.
254 Since drbd-8.4.2 disk-barrier is disabled by default because since
256 linux-2.6.36 (or 2.6.32 RHEL6) there is no reliable way to
257 determine if queuing of IO-barriers works. Dangerous only enable
258 if you are told so by one that knows for sure.
259 When selecting the method you should not only base your decision on
261 the measurable performance. In case your backing storage device has
262 a volatile write cache (plain disks, RAID of plain disks) you
263 should use one of the first two. In case your backing storage
264 device has battery-backed write cache you may go with option 3.
265 Option 4 (disable everything, use "none") is dangerous on most IO
266 stacks, may result in write-reordering, and if so, can
267 theoretically be the reason for data corruption, or disturb the
268 DRBD protocol, causing spurious disconnect/reconnect cycles. Do
269 not use no-disk-drain.
270 Unfortunately device mapper (LVM) might not support barriers.
272 The letter after "wo:" in /proc/drbd indicates with method is
274 currently in use for a device: b, f, d, n. The implementations:
275 barrier
277 The first requires that the driver of the backing storage
278 device support barriers (called 'tagged command queuing' in
279 SCSI and 'native command queuing' in SATA speak). The use of
280 this method can be enabled by setting the disk-barrier options
281 to yes.
282 flush
284 The second requires that the backing device support disk
285 flushes (called 'force unit access' in the drive vendors
286 speak). The use of this method can be disabled setting
287 disk-flushes to no.
288 drain
290 The third method is simply to let write requests drain before
291 write requests of a new reordering domain are issued. That was
292 the only implementation before 8.0.9.
293 none
295 The fourth method is to not express write-after-write
296 dependencies to the backing store at all, by also specifying
297 --no-disk-drain. This is dangerous on most IO stacks, may
298 result in write-reordering, and if so, can theoretically be the
299 reason for data corruption, or disturb the DRBD protocol,
300 causing spurious disconnect/reconnect cycles. Do not use
301 --no-disk-drain.
302 --md-flushes
304 Disables the use of disk flushes and barrier BIOs when accessing
305 the meta data device. See the notes on --disk-flushes.
306 --max-bio-bvecs
308 In some special circumstances the device mapper stack manages to
309 pass BIOs to DRBD that violate the constraints that are set forth
310 by DRBD's merge_bvec() function and which have more than one bvec.
311 A known example is: phys-disk -> DRBD -> LVM -> Xen -> misaligned
312 partition (63) -> DomU FS. Then you might see "bio would need to,
313 but cannot, be split:" in the Dom0's kernel log.
314 The best workaround is to proper align the partition within the VM
316 (E.g. start it at sector 1024). That costs 480 KiB of storage.
317 Unfortunately the default of most Linux partitioning tools is to
318 start the first partition at an odd number (63). Therefore most
319 distributions install helpers for virtual linux machines will end
320 up with misaligned partitions. The second best workaround is to
321 limit DRBD's max bvecs per BIO (i.e., the max-bio-bvecs option) to
322 1, but that might cost performance.
323 The default value of max-bio-bvecs is 0, which means that there is
325 no user imposed limitation.
326 --resync-rate rate
328 To ensure smooth operation of the application on top of DRBD, it is
329 possible to limit the bandwidth that may be used by background
330 synchronization. The default is 250 KiB/sec, the default unit is
331 KiB/sec.
332 --resync-after minor
334 Start resync on this device only if the device with minor is
335 already in connected state. Otherwise this device waits in
336 SyncPause state.
337 --al-extents extents
339 DRBD automatically performs hot area detection. With this parameter
340 you control how big the hot area (=active set) can get. Each extent
341 marks 4M of the backing storage. In case a primary node leaves the
342 cluster unexpectedly, the areas covered by the active set must be
343 resynced upon rejoining of the failed node. The data structure is
344 stored in the meta-data area, therefore each change of the active
345 set is a write operation to the meta-data device. A higher number
346 of extents gives longer resync times but less updates to the
347 meta-data. The default number of extents is 1237. (Minimum: 7,
348 Maximum: 65534)
349 See also drbd.conf(5) and drbdmeta(8) for additional limitations
351 and necessary preparation.
352 --al-updates {yes | no}
354 DRBD's activity log transaction writing makes it possible, that
355 after the crash of a primary node a partial (bit-map based) resync
356 is sufficient to bring the node back to up-to-date. Setting
357 al-updates to no might increase normal operation performance but
358 causes DRBD to do a full resync when a crashed primary gets
359 reconnected. The default value is yes.
360 --c-plan-ahead plan_time,
362 --c-fill-target fill_target,
363 --c-delay-target delay_target,
364 --c-max-rate max_rate
365 The dynamic resync speed controller gets enabled with setting
366 plan_time to a positive value. It aims to fill the buffers along
367 the data path with either a constant amount of data fill_target, or
368 aims to have a constant delay time of delay_target along the path.
369 The controller has an upper bound of max_rate.
370 By plan_time the agility of the controller is configured. Higher
372 values yield for slower/lower responses of the controller to
373 deviation from the target value. It should be at least 5 times RTT.
374 For regular data paths a fill_target in the area of 4k to 100k is
375 appropriate. For a setup that contains drbd-proxy it is advisable
376 to use delay_target instead. Only when fill_target is set to 0 the
377 controller will use delay_target. 5 times RTT is a reasonable
378 starting value. Max_rate should be set to the bandwidth available
379 between the DRBD-hosts and the machines hosting DRBD-proxy, or to
380 the available disk-bandwidth.
381 The default value of plan_time is 0, the default unit is 0.1
383 seconds. Fill_target has 0 and sectors as default unit.
384 Delay_target has 1 (100ms) and 0.1 as default unit. Max_rate has
385 10240 (100MiB/s) and KiB/s as default unit.
386 --c-min-rate min_rate
388 We track the disk IO rate caused by the resync, so we can detect
389 non-resync IO on the lower level device. If the lower level device
390 seems to be busy, and the current resync rate is above min_rate, we
391 throttle the resync.
392 The default value of min_rate is 4M, the default unit is k. If you
394 want to not throttle at all, set it to zero, if you want to
395 throttle always, set it to one.
396 -t, --disk-timeout disk_timeout
398 If the lower-level device on which a DRBD device stores its data
399 does not finish an I/O request within the defined disk-timeout,
400 DRBD treats this as a failure. The lower-level device is detached,
401 and the device's disk state advances to Diskless. If DRBD is
402 connected to one or more peers, the failed request is passed on to
403 one of them.
404 This option is dangerous and may lead to kernel panic!
406 "Aborting" requests, or force-detaching the disk, is intended for
408 completely blocked/hung local backing devices which do no longer
409 complete requests at all, not even do error completions. In this
410 situation, usually a hard-reset and failover is the only way out.
411 By "aborting", basically faking a local error-completion, we allow
413 for a more graceful swichover by cleanly migrating services. Still
414 the affected node has to be rebooted "soon".
415 By completing these requests, we allow the upper layers to re-use
417 the associated data pages.
418 If later the local backing device "recovers", and now DMAs some
420 data from disk into the original request pages, in the best case it
421 will just put random data into unused pages; but typically it will
422 corrupt meanwhile completely unrelated data, causing all sorts of
423 damage.
424 Which means delayed successful completion, especially for READ
426 requests, is a reason to panic(). We assume that a delayed *error*
427 completion is OK, though we still will complain noisily about it.
428 The default value of disk-timeout is 0, which stands for an
430 infinite timeout. Timeouts are specified in units of 0.1 seconds.
431 This option is available since DRBD 8.3.12.
432 --discard-zeroes-if-aligned {yes | no}
434 Setting discard-zeroes-if-aligned to no will cause DRBD to always
435 fall-back to zero-out on the receiving side, and to not even
436 announce discard capabilities on the Primary, if the respective
437 backend announces discard_zeroes_data=false.
438 Setting discards-zeroes-if-aligned to yes will allow DRBD to use
440 discards, and to announce discard_zeroes=true, even on backends
441 that announce discard_zeroes_data=false.
442 We used to ignore the discard_zeroes_data setting completely. To
444 not break established and expected behaviour, the default value is
445 yes.
446 This option is available since 8.4.7. See also drbd.conf(5).
448 --read-balancing method
450 The supported methods for load balancing of read requests are
451 prefer-local, prefer-remote, round-robin, least-pending and
452 when-congested-remote, 32K-striping, 64K-striping, 128K-striping,
453 256K-striping, 512K-striping and 1M-striping.
454 The default value of is prefer-local. This option is available
456 since 8.4.1.
457 --rs-discard-granularity bytes
459 When rs-discard-granularity is set to a non zero, positive value
460 then DRBD tries to do a resync operation in requests of this size.
461 In case such a block contains only zero bytes on the sync source
462 node, the sync target node will issue a discard/trim/unmap command
463 for the area.
464 The value is constrained by the discard granularity of the backing
466 block device. In case rs-discard-granularity is not a multiplier of
467 the discard granularity of the backing block device DRBD rounds it
468 up. The feature only gets active if the backing block device reads
469 back zeroes after a discard command.
470 The default value of is 0. This option is available since 8.4.7.
472 connect, net-options
474 Connect sets up the device to listen on af:local_addr:port for incoming
475 connections and to try to connect to af:remote_addr:port. If port is
476 omitted, 7788 is used as default. If af is omitted ipv4 gets used.
477 Other supported address families are ipv6, ssocks for Dolphin
478 Interconnect Solutions' "super sockets" and sdp for Sockets Direct
479 Protocol (Infiniband).
480 The net-options command allows you to change options while the
482 connection is established.
483 --protocol protocol
485 On the TCP/IP link the specified protocol is used. Valid protocol
486 specifiers are A, B, and C.
487 Protocol A: write IO is reported as completed, if it has reached
489 local disk and local TCP send buffer.
490 Protocol B: write IO is reported as completed, if it has reached
492 local disk and remote buffer cache.
493 Protocol C: write IO is reported as completed, if it has reached
495 both local and remote disk.
496 --connect-int time
498 In case it is not possible to connect to the remote DRBD device
499 immediately, DRBD keeps on trying to connect. With this option you
500 can set the time between two retries. The default value is 10. The
501 unit is seconds.
502 --ping-int time
504 If the TCP/IP connection linking a DRBD device pair is idle for
505 more than time seconds, DRBD will generate a keep-alive packet to
506 check if its partner is still alive. The default value is 10. The
507 unit is seconds.
508 --timeout val
510 If the partner node fails to send an expected response packet
511 within val tenths of a second, the partner node is considered dead
512 and therefore the TCP/IP connection is abandoned. The default value
513 is 60 (= 6 seconds).
514 --sndbuf-size size
516 The socket send buffer is used to store packets sent to the
517 secondary node, which are not yet acknowledged (from a network
518 point of view) by the secondary node. When using protocol A, it
519 might be necessary to increase the size of this data structure in
520 order to increase asynchronicity between primary and secondary
521 nodes. But keep in mind that more asynchronicity is synonymous with
522 more data loss in the case of a primary node failure. Since 8.0.13
523 resp. 8.2.7 setting the size value to 0 means that the kernel
524 should autotune this. The default size is 0, i.e. autotune.
525 --rcvbuf-size size
527 Packets received from the network are stored in the socket receive
528 buffer first. From there they are consumed by DRBD. Before 8.3.2
529 the receive buffer's size was always set to the size of the socket
530 send buffer. Since 8.3.2 they can be tuned independently. A value
531 of 0 means that the kernel should autotune this. The default size
532 is 0, i.e. autotune.
533 --ko-count count
535 In case the secondary node fails to complete a single write request
536 for count times the timeout, it is expelled from the cluster, i.e.
537 the primary node goes into StandAlone mode. To disable this
538 feature, you should explicitly set it to 0; defaults may change
539 between versions.
540 --max-epoch-size val
542 With this option the maximal number of write requests between two
543 barriers is limited. Typically set to the same as --max-buffers, or
544 the allowed maximum. Values smaller than 10 can lead to degraded
545 performance. The default value is 2048.
546 --max-buffers val
548 With this option the maximal number of buffer pages allocated by
549 DRBD's receiver thread is limited. Typically set to the same as
550 --max-epoch-size. Small values could lead to degraded performance.
551 The default value is 2048, the minimum 32. Increase this if you
552 cannot saturate the IO backend of the receiving side during linear
553 write or during resync while otherwise idle.
554 See also drbd.conf(5)
556 --unplug-watermark val
558 This setting has no effect with recent kernels that use explicit
559 on-stack plugging (upstream Linux kernel 2.6.39, distributions may
560 have backported).
561 When the number of pending write requests on the standby
563 (secondary) node exceeds the unplug-watermark, we trigger the
564 request processing of our backing storage device. Some storage
565 controllers deliver better performance with small values, others
566 deliver best performance when the value is set to the same value as
567 max-buffers, yet others don't feel much effect at all. Minimum 16,
568 default 128, maximum 131072.
569 --allow-two-primaries
571 With this option set you may assign primary role to both nodes. You
572 only should use this option if you use a shared storage file system
573 on top of DRBD. At the time of writing the only ones are: OCFS2 and
574 GFS. If you use this option with any other file system, you are
575 going to crash your nodes and to corrupt your data!
576 --cram-hmac-alg alg
578 You need to specify the HMAC algorithm to enable peer
579 authentication at all. You are strongly encouraged to use peer
580 authentication. The HMAC algorithm will be used for the challenge
581 response authentication of the peer. You may specify any digest
582 algorithm that is named in /proc/crypto.
583 --shared-secret secret
585 The shared secret used in peer authentication. May be up to 64
586 characters.
587 --after-sb-0pri asb-0p-policy
589 possible policies are:
590 disconnect
592 No automatic resynchronization, simply disconnect.
593 discard-younger-primary
595 Auto sync from the node that was primary before the split-brain
596 situation occurred.
597 discard-older-primary
599 Auto sync from the node that became primary as second during
600 the split-brain situation.
601 discard-zero-changes
603 In case one node did not write anything since the split brain
604 became evident, sync from the node that wrote something to the
605 node that did not write anything. In case none wrote anything
606 this policy uses a random decision to perform a "resync" of 0
607 blocks. In case both have written something this policy
608 disconnects the nodes.
609 discard-least-changes
611 Auto sync from the node that touched more blocks during the
612 split brain situation.
613 discard-node-NODENAME
615 Auto sync to the named node.
616 --after-sb-1pri asb-1p-policy
618 possible policies are:
619 disconnect
621 No automatic resynchronization, simply disconnect.
622 consensus
624 Discard the version of the secondary if the outcome of the
625 after-sb-0pri algorithm would also destroy the current
626 secondary's data. Otherwise disconnect.
627 discard-secondary
629 Discard the secondary's version.
630 call-pri-lost-after-sb
632 Always honor the outcome of the after-sb-0pri algorithm. In
633 case it decides the current secondary has the correct data,
634 call the pri-lost-after-sb on the current primary.
635 violently-as0p
637 Always honor the outcome of the after-sb-0pri algorithm. In
638 case it decides the current secondary has the correct data,
639 accept a possible instantaneous change of the primary's data.
640 --after-sb-2pri asb-2p-policy
642 possible policies are:
643 disconnect
645 No automatic resynchronization, simply disconnect.
646 call-pri-lost-after-sb
648 Always honor the outcome of the after-sb-0pri algorithm. In
649 case it decides the current secondary has the right data, call
650 the pri-lost-after-sb on the current primary.
651 violently-as0p
653 Always honor the outcome of the after-sb-0pri algorithm. In
654 case it decides the current secondary has the right data,
655 accept a possible instantaneous change of the primary's data.
656 --always-asbp
658 Normally the automatic after-split-brain policies are only used if
659 current states of the UUIDs do not indicate the presence of a third
660 node.
661 With this option you request that the automatic after-split-brain
663 policies are used as long as the data sets of the nodes are somehow
664 related. This might cause a full sync, if the UUIDs indicate the
665 presence of a third node. (Or double faults have led to strange
666 UUID sets.)
667 --rr-conflict role-resync-conflict-policy
669 This option sets DRBD's behavior when DRBD deduces from its meta
670 data that a resynchronization is needed, and the SyncTarget node is
671 already primary. The possible settings are: disconnect,
672 call-pri-lost and violently. While disconnect speaks for itself,
673 with the call-pri-lost setting the pri-lost handler is called which
674 is expected to either change the role of the node to secondary, or
675 remove the node from the cluster. The default is disconnect.
676 With the violently setting you allow DRBD to force a primary node
678 into SyncTarget state. This means that the data exposed by DRBD
679 changes to the SyncSource's version of the data instantaneously.
680 USE THIS OPTION ONLY IF YOU KNOW WHAT YOU ARE DOING.
681 --data-integrity-alg hash_alg
683 DRBD can ensure the data integrity of the user's data on the
684 network by comparing hash values. Normally this is ensured by the
685 16 bit checksums in the headers of TCP/IP packets. This option can
686 be set to any of the kernel's data digest algorithms. In a typical
687 kernel configuration you should have at least one of md5, sha1, and
688 crc32c available. By default this is not enabled.
689 See also the notes on data integrity on the drbd.conf manpage.
691 --no-tcp-cork
693 DRBD usually uses the TCP socket option TCP_CORK to hint to the
694 network stack when it can expect more data, and when it should
695 flush out what it has in its send queue. There is at least one
696 network stack that performs worse when one uses this hinting
697 method. Therefore we introduced this option, which disable the
698 setting and clearing of the TCP_CORK socket option by DRBD.
699 --ping-timeout ping_timeout
701 The time the peer has to answer to a keep-alive packet. In case the
702 peer's reply is not received within this time period, it is
703 considered dead. The default unit is tenths of a second, the
704 default value is 5 (for half a second).
705 --discard-my-data
707 Use this option to manually recover from a split-brain situation.
708 In case you do not have any automatic after-split-brain policies
709 selected, the nodes refuse to connect. By passing this option you
710 make this node a sync target immediately after successful connect.
711 --tentative
713 Causes DRBD to abort the connection process after the resync
714 handshake, i.e. no resync gets performed. You can find out which
715 resync DRBD would perform by looking at the kernel's log file.
716 --on-congestion congestion_policy,
718 --congestion-fill fill_threshold,
719 --congestion-extents active_extents_threshold
720 By default DRBD blocks when the available TCP send queue becomes
721 full. That means it will slow down the application that generates
722 the write requests that cause DRBD to send more data down that TCP
723 connection.
724 When DRBD is deployed with DRBD-proxy it might be more desirable
726 that DRBD goes into AHEAD/BEHIND mode shortly before the send queue
727 becomes full. In AHEAD/BEHIND mode DRBD does no longer replicate
728 data, but still keeps the connection open.
729 The advantage of the AHEAD/BEHIND mode is that the application is
731 not slowed down, even if DRBD-proxy's buffer is not sufficient to
732 buffer all write requests. The downside is that the peer node falls
733 behind, and that a resync will be necessary to bring it back into
734 sync. During that resync the peer node will have an inconsistent
735 disk.
736 Available congestion_policys are block and pull-ahead. The default
738 is block. Fill_threshold might be in the range of 0 to 10GiBytes.
739 The default is 0 which disables the check.
740 Active_extents_threshold has the same limits as al-extents.
741 The AHEAD/BEHIND mode and its settings are available since DRBD
743 8.3.10.
744 --verify-alg hash-alg
746 During online verification (as initiated by the verify
747 sub-command), rather than doing a bit-wise comparison, DRBD applies
748 a hash function to the contents of every block being verified, and
749 compares that hash with the peer. This option defines the hash
750 algorithm being used for that purpose. It can be set to any of the
751 kernel's data digest algorithms. In a typical kernel configuration
752 you should have at least one of md5, sha1, and crc32c available. By
753 default this is not enabled; you must set this option explicitly in
754 order to be able to use on-line device verification.
755 See also the notes on data integrity on the drbd.conf manpage.
757 --csums-alg hash-alg
759 A resync process sends all marked data blocks from the source to
760 the destination node, as long as no csums-alg is given. When one is
761 specified the resync process exchanges hash values of all marked
762 blocks first, and sends only those data blocks over, that have
763 different hash values.
764 This setting is useful for DRBD setups with low bandwidth links.
766 During the restart of a crashed primary node, all blocks covered by
767 the activity log are marked for resync. But a large part of those
768 will actually be still in sync, therefore using csums-alg will
769 lower the required bandwidth in exchange for CPU cycles.
770 --use-rle
772 During resync-handshake, the dirty-bitmaps of the nodes are
773 exchanged and merged (using bit-or), so the nodes will have the
774 same understanding of which blocks are dirty. On large devices, the
775 fine grained dirty-bitmap can become large as well, and the bitmap
776 exchange can take quite some time on low-bandwidth links.
777 Because the bitmap typically contains compact areas where all bits
779 are unset (clean) or set (dirty), a simple run-length encoding
780 scheme can considerably reduce the network traffic necessary for
781 the bitmap exchange.
782 For backward compatibility reasons, and because on fast links this
784 possibly does not improve transfer time but consumes cpu cycles,
785 this defaults to off.
786 Introduced in 8.3.2.
788 --socket-check-timeout
790 In setups involving a DRBD-proxy and connections that experience a
791 lot of buffer-bloat it might be necessary to set ping-timeout to an
792 unusual high value. By default DRBD uses the same value to wait if
793 a newly established TCP-connection is stable. Since the DRBD-proxy
794 is usually located in the same data center such a long wait time
795 may hinder DRBD's connect process.
796 In such setups socket-check-timeout should be set to at least to
798 the round trip time between DRBD and DRBD-proxy. I.e. in most cases
799 to 1.
800 The default unit is tenths of a second, the default value is 0
802 (which causes DRBD to use the value of ping-timeout instead).
803 Introduced in 8.4.5.
804 resource-options
806 Changes the options of the resource at runtime.
807 --cpu-mask cpu-mask
809 Sets the cpu-affinity-mask for DRBD's kernel threads of this
810 device. The default value of cpu-mask is 0, which means that DRBD's
811 kernel threads should be spread over all CPUs of the machine. This
812 value must be given in hexadecimal notation. If it is too big it
813 will be truncated.
814 --on-no-data-accessible ond-policy
816 This setting controls what happens to IO requests on a degraded,
817 disk less node (I.e. no data store is reachable). The available
818 policies are io-error and suspend-io.
819 If ond-policy is set to suspend-io you can either resume IO by
821 attaching/connecting the last lost data storage, or by the drbdadm
822 resume-io res command. The latter will result in IO errors of
823 course.
824 The default is io-error. This setting is available since DRBD
826 8.3.9.
827 primary
829 Sets the device into primary role. This means that applications (e.g. a
830 file system) may open the device for read and write access. Data
831 written to the device in primary role are mirrored to the device in
832 secondary role.
833 Normally it is not possible to set both devices of a connected DRBD
835 device pair to primary role. By using the --allow-two-primaries option,
836 you override this behavior and instruct DRBD to allow two primaries.
837 --overwrite-data-of-peer
839 Alias for --force.
840 --force
842 Becoming primary fails if the local replica is not up-to-date. I.e.
843 when it is inconsistent, outdated of consistent. By using this
844 option you can force it into primary role anyway. USE THIS OPTION
845 ONLY IF YOU KNOW WHAT YOU ARE DOING.
846 secondary
848 Brings the device into secondary role. This operation fails as long as
849 at least one application (or file system) has opened the device.
850 It is possible that both devices of a connected DRBD device pair are
852 secondary.
853 verify
855 This initiates on-line device verification. During on-line
856 verification, the contents of every block on the local node are
857 compared to those on the peer node. Device verification progress can be
858 monitored via /proc/drbd. Any blocks whose content differs from that of
859 the corresponding block on the peer node will be marked out-of-sync in
860 DRBD's on-disk bitmap; they are not brought back in sync automatically.
861 To do that, simply disconnect and reconnect the resource.
862 If on-line verification is already in progress (and this node is
864 "VerifyS"), this command silently "succeeds". In this case, any
865 start-sector (see below) will be ignored, and any stop-sector (see
866 below) will be honored. This can be used to stop a running verify, or
867 to update/shorten/extend the coverage of the currently running verify.
868 This command will fail if the device is not part of a connected device
870 pair.
871 See also the notes on data integrity on the drbd.conf manpage.
873 --start start-sector
875 Since version 8.3.2, on-line verification should resume from the
876 last position after connection loss. It may also be started from an
877 arbitrary position by setting this option. If you had reached some
878 stop-sector before, and you do not specify an explicit
879 start-sector, verify should resume from the previous stop-sector.
880 Default unit is sectors. You may also specify a unit explicitly.
882 The start-sector will be rounded down to a multiple of 8 sectors
883 (4kB).
884 -S, --stop stop-sector
886 Since version 8.3.14, on-line verification can be stopped before it
887 reaches end-of-device.
888 Default unit is sectors. You may also specify a unit explicitly.
890 The stop-sector may be updated by issuing an additional drbdsetup
891 verify command on the same node while the verify is running. This
892 can be used to stop a running verify, or to update/shorten/extend
893 the coverage of the currently running verify.
894 invalidate
896 This forces the local device of a pair of connected DRBD devices into
897 SyncTarget state, which means that all data blocks of the device are
898 copied over from the peer.
899 This command will fail if the device is not either part of a connected
901 device pair, or disconnected Secondary.
902 invalidate-remote
904 This forces the local device of a pair of connected DRBD devices into
905 SyncSource state, which means that all data blocks of the device are
906 copied to the peer.
907 On a disconnected Primary device, this will set all bits in the out of
909 sync bitmap. As a side affect this suspends updates to the on disk
910 activity log. Updates to the on disk activity log resume automatically
911 when necessary.
912 wait-connect
914 Returns as soon as the device can communicate with its partner device.
915 --wfc-timeout wfc_timeout,
917 --degr-wfc-timeout degr_wfc_timeout,
918 --outdated-wfc-timeout outdated_wfc_timeout,
919 --wait-after-sb
920 This command will fail if the device cannot communicate with its
921 partner for timeout seconds. If the peer was working before this
922 node was rebooted, the wfc_timeout is used. If the peer was already
923 down before this node was rebooted, the degr_wfc_timeout is used.
924 If the peer was successfully outdated before this node was rebooted
925 the outdated_wfc_timeout is used. The default value for all those
926 timeout values is 0 which means to wait forever. The unit is
927 seconds. In case the connection status goes down to StandAlone
928 because the peer appeared but the devices had a split brain
929 situation, the default for the command is to terminate. You can
930 change this behavior with the --wait-after-sb option.
931 wait-sync
933 Returns as soon as the device leaves any synchronization into connected
934 state. The options are the same as with the wait-connect command.
935 disconnect
937 Removes the information set by the net command from the device. This
938 means that the device goes into unconnected state and will no longer
939 listen for incoming connections.
940 detach
942 Removes the information set by the disk command from the device. This
943 means that the device is detached from its backing storage device.
944 -f, --force
946 A regular detach returns after the disk state finally reached
947 diskless. As a consequence detaching from a frozen backing block
948 device never terminates.
949 On the other hand A forced detach returns immediately. It allows
951 you to detach DRBD from a frozen backing block device. Please note
952 that the disk will be marked as failed until all pending IO
953 requests where finished by the backing block device.
954 down
956 Removes all configuration information from the device and forces it
957 back to unconfigured state.
958 role
960 Shows the current roles of the device and its peer, as local/peer.
961 state
963 Deprecated alias for "role"
964 cstate
966 Shows the current connection state of the device.
967 dstate
969 Shows the current states of the backing storage devices, as local/peer.
970 resize
972 This causes DRBD to reexamine the size of the device's backing storage
973 device. To actually do online growing you need to extend the backing
974 storages on both devices and call the resize command on one of your
975 nodes.
976 The --size option can be used to online shrink the usable size of a
978 drbd device. It's the users responsibility to make sure that a file
979 system on the device is not truncated by that operation.
980 The --assume-peer-has-space allows you to resize a device which is
982 currently not connected to the peer. Use with care, since if you do not
983 resize the peer's disk as well, further connect attempts of the two
984 will fail.
985 When the --assume-clean option is given DRBD will skip the resync of
987 the new storage. Only do this if you know that the new storage was
988 initialized to the same content by other means.
989 The options --al-stripes and --al-stripe-size-kB may be used to change
991 the layout of the activity log online. In case of internal meta data
992 this may invovle shrinking the user visible size at the same time
993 (unsing the --size) or increasing the avalable space on the backing
994 devices.
995 check-resize
997 To enable DRBD to detect offline resizing of backing devices this
998 command may be used to record the current size of backing devices. The
999 size is stored in files in /var/lib/drbd/ named drbd-minor-??.lkbd
1000 This command is called by drbdadm resize res after drbdsetup device
1002 resize returned.
1003 pause-sync
1005 Temporarily suspend an ongoing resynchronization by setting the local
1006 pause flag. Resync only progresses if neither the local nor the remote
1007 pause flag is set. It might be desirable to postpone DRBD's
1008 resynchronization after eventual resynchronization of the backing
1009 storage's RAID setup.
1010 resume-sync
1012 Unset the local sync pause flag.
1013 outdate
1015 Mark the data on the local backing storage as outdated. An outdated
1016 device refuses to become primary. This is used in conjunction with
1017 fencing and by the peer's fence-peer handler.
1018 show-gi
1020 Displays the device's data generation identifiers verbosely.
1021 get-gi
1023 Displays the device's data generation identifiers.
1024 show
1026 Shows all available configuration information of a resource, or of all
1027 resources. Available options:
1028 --show-defaults
1030 Show all configuration parameters, even the ones with default
1031 values. Normally, parameters with default values are not shown.
1032 suspend-io
1034 This command is of no apparent use and just provided for the sake of
1035 completeness.
1036 resume-io
1038 If the fence-peer handler fails to stonith the peer node, and your
1039 fencing policy is set to resource-and-stonith, you can unfreeze IO
1040 operations with this command.
1041 status
1043 Show the status of a resource, or of all resources. The output consists
1044 of one paragraph for each configured resource. Each paragraph contains
1045 one line for each resource, followed by one line for each device, and
1046 one line for each connection. The device and connection lines are
1047 indented. The connection lines are followed by one line for each peer
1048 device; these lines are indented against the connection line.
1049 Long lines are wrapped around at terminal width, and indented to
1051 indicate how the lines belongs together. Available options:
1052 --verbose
1054 Include more information in the output even when it is likely
1055 redundant or irrelevant.
1056 --statistics
1058 Include data transfer statistics in the output.
1059 --color={always | auto | never}
1061 Colorize the output. With --color=auto, drbdsetup emits color codes
1062 only when standard output is connected to a terminal.
1063 For example, the non-verbose output for a resource with only one
1065 connection and only one volume could look like this:
1066 fs-backoffice role:Primary
1068 disk:UpToDate
1069 peer role:Secondary
1070 replication:Established peer-disk:UpToDate
1071 With the --verbose --statistics options, the same resource could be
1074 reported as:
1075 fs-data role:Primary suspended:no
1077 write-ordering:drain
1078 volume:0 minor:1 disk:UpToDate
1079 size:10616472 read:134465 written:144800 al-writes:18 bm-writes:0
1080 upper-pending:0 lower-pending:0 al-suspended:no blocked:no
1081 peer connection:Connected role:Secondary congested:no
1082 volume:0 replication:Established peer-disk:UpToDate resync-suspended:no
1083 received:122596 sent:22204 out-of-sync:0 pending:0 unacked:0
1084 events2
1088 Show the current state of all configured DRBD objects, followed by all
1089 changes to the state.
1090 The output format is meant to be human as well as machine readable.
1092 Each line starts with the event number, which is followed by an
1093 asterisk if the event continues in the next line. The second word in
1094 each line indicates the kind of event: exists for an existing object;
1095 create, destroy, and change if an object is created, destroyed, or
1096 changed; or call or response if an event handler is called or it
1097 returns. The third word indicates the object the event applies to:
1098 resource, device, connection, peer-device, helper, or a dash (-) to
1099 indicate that the current state has been dumped completely.
1100 The remaining words identify the object and describe the state that he
1102 object is in. Available options:
1103 --now
1105 Terminate after reporting the current state. The default is to
1106 continuously listen and report state changes.
1107 --statistics
1109 Include statistics in the output.
1110 events
1112 Deprecated. If possible, change to the events2 subcommand instead.
1113 Displays every state change of DRBD and all calls to helper programs.
1115 This might be used to get notified of DRBD's state changes by piping
1116 the output to another program.
1117 --all-devices
1119 Display the events of all DRBD minors.
1120 --unfiltered
1122 This is a debugging aid that displays the content of all received
1123 netlink messages.
1124 new-current-uuid
1126 Generates a new current UUID and rotates all other UUID values. This
1127 has at least two use cases, namely to skip the initial sync, and to
1128 reduce network bandwidth when starting in a single node configuration
1129 and then later (re-)integrating a remote site.
1130 Available option:
1132 --clear-bitmap
1134 Clears the sync bitmap in addition to generating a new current
1135 UUID.
1136 This can be used to skip the initial sync, if you want to start from
1138 scratch. This use-case does only work on "Just Created" meta data.
1139 Necessary steps:
1140 1. On both nodes, initialize meta data and configure the device.
1142 drbdadm -- --force create-md res
1144 2. They need to do the initial handshake, so they know their sizes.
1146 drbdadm up res
1148 3. They are now Connected Secondary/Secondary
1150 Inconsistent/Inconsistent. Generate a new current-uuid and clear
1151 the dirty bitmap.
1152 drbdadm new-current-uuid --clear-bitmap res
1154 4. They are now Connected Secondary/Secondary UpToDate/UpToDate. Make
1156 one side primary and create a file system.
1157 drbdadm primary res
1159 mkfs -t fs-type $(drbdadm sh-dev res)
1161 One obvious side-effect is that the replica is full of old garbage
1163 (unless you made them identical using other means), so any
1164 online-verify is expected to find any number of out-of-sync blocks.
1165 You must not use this on pre-existing data! Even though it may appear
1167 to work at first glance, once you switch to the other node, your data
1168 is toast, as it never got replicated. So do not leave out the mkfs (or
1169 equivalent).
1170 This can also be used to shorten the initial resync of a cluster where
1172 the second node is added after the first node is gone into production,
1173 by means of disk shipping. This use-case works on disconnected devices
1174 only, the device may be in primary or secondary role.
1175 The necessary steps on the current active server are:
1177 1. drbdsetup new-current-uuid --clear-bitmap minor
1179 2. Take the copy of the current active server. E.g. by pulling a disk
1181 out of the RAID1 controller, or by copying with dd. You need to
1182 copy the actual data, and the meta data.
1183 3. drbdsetup new-current-uuid minor
1185 Now add the disk to the new secondary node, and join it to the cluster.
1187 You will get a resync of that parts that were changed since the first
1188 call to drbdsetup in step 1.
1189
1191 For examples, please have a look at the DRBD User's Guide[1].
1192
1194 This document was revised for version 8.3.2 of the DRBD distribution.
1195
1197 Written by Philipp Reisner <philipp.reisner@linbit.com> and Lars
1198 Ellenberg <lars.ellenberg@linbit.com>
1199
1201 Report bugs to <drbd-user@lists.linbit.com>.
1202
1204 Copyright 2001-2008 LINBIT Information Technologies, Philipp Reisner,
1205 Lars Ellenberg. This is free software; see the source for copying
1206 conditions. There is NO warranty; not even for MERCHANTABILITY or
1207 FITNESS FOR A PARTICULAR PURPOSE.
1208
1210 drbd.conf(5), drbd(8), drbddisk(8), drbdadm(8), DRBD User's Guide[1],
1211 DRBD web site[2]
1212
1214 1. DRBD User's Guide
1215 http://www.drbd.org/users-guide/
1216 2. DRBD web site
1218 http://www.drbd.org/
1219DRBD 8.4.0 6 May 2011 DRBDSETUP(8)