1DRBDSETUP(8) System Administration DRBDSETUP(8)
2
6 drbdsetup - Setup tool for DRBD
7
9 drbdsetup {device} disk {lower_dev} {meta_data_dev} {meta_data_index}
10 [-d {size}] [-e {err_handler}] [-f {fencing_policy}] [-b]
11 [-t {disk_timeout}]
12 drbdsetup {device} net [af:] {local_addr} [:port] [af:] {remote_addr}
14 [:port] {protocol} [-c {time}] [-i {time}] [-t {val}]
15 [-S {size}] [-r {size}] [-k {count}] [-e {max_epoch_size}]
16 [-b {max_buffers}] [-m] [-a {hash_alg}] [-x {shared_secret}]
17 [-A {asb-0p-policy}] [-B {asb-1p-policy}]
18 [-C {asb-2p-policy}] [-D] [-R {role-resync-conflict-policy}]
19 [-p {ping_timeout}] [-u {val}] [-d {hash_alg}] [-o] [-n]
20 [-g {congestion_policy}] [-f {val}] [-h {val}]
21 drbdsetup {device} syncer [-a {dev_minor}] [-r {rate}] [-e {extents}]
23 [-v {verify-hash-alg}] [-c {cpu-mask}] [-C {csums-hash-alg}]
24 [-R] [-p {plan_time}] [-s {fill_target}] [-d {delay_target}]
25 [-m {max_rate}] [-n {ond-policy}]
26 drbdsetup {device} disconnect
28 drbdsetup {device} detach [-f]
30 drbdsetup {device} down
32 drbdsetup {device} primary [-f] [-o]
34 drbdsetup {device} secondary
36 drbdsetup {device} verify [-s {start-position}] [-S {stop-position}]
38 drbdsetup {device} invalidate
40 drbdsetup {device} invalidate-remote
42 drbdsetup {device} wait-connect [-t {wfc_timeout}]
44 [-d {degr_wfc_timeout}] [-o {outdated_wfc_timeout}] [-w]
45 drbdsetup {device} wait-sync [-t {wfc_timeout}] [-d {degr_wfc_timeout}]
47 [-o {outdated_wfc_timeout}] [-w]
48 drbdsetup {device} role
50 drbdsetup {device} cstate
52 drbdsetup {device} dstate
54 drbdsetup {device} status
56 drbdsetup {device} resize [-d {size}] [-f {assume-peer-has-space}]
58 [-c {assume-clean}]
59 drbdsetup {device} check-resize
61 drbdsetup {device} pause-sync
63 drbdsetup {device} resume-sync
65 drbdsetup {device} outdate
67 drbdsetup {device} show-gi
69 drbdsetup {device} get-gi
71 drbdsetup {device} show
73 drbdsetup {device} suspend-io
75 drbdsetup {device} resume-io
77 drbdsetup {device} events [-u] [-a]
79 drbdsetup {device} new-current-uuid [-c]
81
83 drbdsetup is used to associate DRBD devices with their backing block
84 devices, to set up DRBD device pairs to mirror their backing block
85 devices, and to inspect the configuration of running DRBD devices.
86
88 drbdsetup is a low level tool of the DRBD program suite. It is used by
89 the data disk and drbd scripts to communicate with the device driver.
90
92 Each drbdsetup sub-command might require arguments and bring its own
93 set of options. All values have default units which might be overruled
94 by K, M or G. These units are defined in the usual way (e.g. K = 2^10 =
95 1024).
96 Common options
98 All drbdsetup sub-commands accept these two options
99 --create-device
101 In case the specified DRBD device (minor number) does not exist
102 yet, create it implicitly.
103 --set-defaults
105 When --set-defaults is given on the command line, all options of
106 the invoked sub-command that are not explicitly set are reset to
107 their default values.
108 disk
110 Associates device with lower_device to store its data blocks on. The -d
111 (or --disk-size) should only be used if you wish not to use as much as
112 possible from the backing block devices. If you do not use -d, the
113 device is only ready for use as soon as it was connected to its peer
114 once. (See the net command.)
115 -d, --disk-size size
117 You can override DRBD's size determination method with this option.
118 If you need to use the device before it was ever connected to its
119 peer, use this option to pass the size of the DRBD device to the
120 driver. Default unit is sectors (1s = 512 bytes).
121 If you use the size parameter in drbd.conf, we strongly recommend
123 to add an explicit unit postfix. drbdadm and drbdsetup used to have
124 mismatching default units.
125 -e, --on-io-error err_handler
127 If the driver of the lower_device reports an error to DRBD, DRBD
128 will mark the disk as inconsistent, call a helper program, or
129 detach the device from its backing storage and perform all further
130 IO by requesting it from the peer. The valid err_handlers are:
131 pass_on, call-local-io-error and detach.
132 -f, --fencing fencing_policy
134 Under fencing we understand preventive measures to avoid situations
135 where both nodes are primary and disconnected (AKA split brain).
136 Valid fencing policies are:
138 dont-care
140 This is the default policy. No fencing actions are done.
141 resource-only
143 If a node becomes a disconnected primary, it tries to outdate
144 the peer's disk. This is done by calling the fence-peer
145 handler. The handler is supposed to reach the other node over
146 alternative communication paths and call 'drbdadm outdate res'
147 there.
148 resource-and-stonith
150 If a node becomes a disconnected primary, it freezes all its IO
151 operations and calls its fence-peer handler. The fence-peer
152 handler is supposed to reach the peer over alternative
153 communication paths and call 'drbdadm outdate res' there. In
154 case it cannot reach the peer, it should stonith the peer. IO
155 is resumed as soon as the situation is resolved. In case your
156 handler fails, you can resume IO with the resume-io command.
157 -b, --use-bmbv
159 In case the backing storage's driver has a merge_bvec_fn()
160 function, DRBD has to pretend that it can only process IO requests
161 in units not larger than 4 KiB. (At time of writing the only known
162 drivers which have such a function are: md (software raid driver),
163 dm (device mapper - LVM) and DRBD itself)
164 To get best performance out of DRBD on top of software raid (or any
166 other driver with a merge_bvec_fn() function) you might enable this
167 option, if you know for sure that the merge_bvec_fn() function will
168 deliver the same results on all nodes of your cluster. I.e. the
169 physical disks of the software raid are exactly of the same type.
170 USE THIS OPTION ONLY IF YOU KNOW WHAT YOU ARE DOING.
171 -a, --no-disk-barrier, -i, --no-disk-flushes, -D, --no-disk-drain
173 DRBD has four implementations to express write-after-write
174 dependencies to its backing storage device. DRBD will use the first
175 method that is supported by the backing storage device and that is
176 not disabled by the user.
177 When selecting the method you should not only base your decision on
179 the measurable performance. In case your backing storage device has
180 a volatile write cache (plain disks, RAID of plain disks) you
181 should use one of the first two. In case your backing storage
182 device has battery-backed write cache you may go with option 3.
183 Option 4 (disable everything, use "none") is dangerous on most IO
184 stacks, may result in write-reordering, and if so, can
185 theoretically be the reason for data corruption, or disturb the
186 DRBD protocol, causing spurious disconnect/reconnect cycles. Do
187 not use no-disk-drain.
188 Unfortunately device mapper (LVM) might not support barriers.
190 The letter after "wo:" in /proc/drbd indicates with method is
192 currently in use for a device: b, f, d, n. The implementations:
193 barrier
195 The first requires that the driver of the backing storage
196 device support barriers (called 'tagged command queuing' in
197 SCSI and 'native command queuing' in SATA speak). The use of
198 this method can be disabled by the --no-disk-barrier option.
199 Note: Since Linux-2.6.36 (or RHEL's 2.6.32) this method is
200 disabled.
201 flush
203 The second requires that the backing device support disk
204 flushes (called 'force unit access' in the drive vendors
205 speak). The use of this method can be disabled using the
206 --no-disk-flushes option.
207 drain
209 The third method is simply to let write requests drain before
210 write requests of a new reordering domain are issued. That was
211 the only implementation before 8.0.9.
212 none
214 The fourth method is to not express write-after-write
215 dependencies to the backing store at all, by also specifying
216 --no-disk-drain. This is dangerous on most IO stacks, may
217 result in write-reordering, and if so, can theoretically be the
218 reason for data corruption, or disturb the DRBD protocol,
219 causing spurious disconnect/reconnect cycles. Do not use
220 --no-disk-drain.
221 -m, --no-md-flushes
223 Disables the use of disk flushes and barrier BIOs when accessing
224 the meta data device. See the notes on --no-disk-flushes.
225 -s, --max-bio-bvecs
227 In some special circumstances the device mapper stack manages to
228 pass BIOs to DRBD that violate the constraints that are set forth
229 by DRBD's merge_bvec() function and which have more than one bvec.
230 A known example is: phys-disk -> DRBD -> LVM -> Xen -> missaligned
231 partition (63) -> DomU FS. Then you might see "bio would need to,
232 but cannot, be split:" in the Dom0's kernel log.
233 The best workaround is to proper align the partition within the VM
235 (E.g. start it at sector 1024). That costs 480 KiB of storage.
236 Unfortunately the default of most Linux partitioning tools is to
237 start the first partition at an odd number (63). Therefore most
238 distributions install helpers for virtual linux machines will end
239 up with missaligned partitions. The second best workaround is to
240 limit DRBD's max bvecs per BIO (i.e., the max-bio-bvecs option) to
241 1, but that might cost performance.
242 The default value of max-bio-bvecs is 0, which means that there is
244 no user imposed limitation.
245 -t, --disk-timeout disk_timeout
247 If the driver of the lower_device does not finish an IO request
248 within disk_timeout, DRBD considers the disk as failed. If DRBD is
249 connected to a remote host, it will reissue local pending IO
250 requests to the peer, and ship all new IO requests to the peer
251 only. The disk state advances to diskless, as soon as the backing
252 block device has finished all IO requests.
253 The default value of is 0, which means that no timeout is enforced.
255 The default unit is 100ms. This option is available since 8.3.12.
256 net
258 Sets up the device to listen on af:local_addr:port for incoming
259 connections and to try to connect to af:remote_addr:port. If port is
260 omitted, 7788 is used as default. If af is omitted ipv4 gets used.
261 Other supported address families are ipv6, ssocks for Dolphin
262 Interconnect Solutions' "super sockets" and sdp for Sockets Direct
263 Protocol (Infiniband).
264 On the TCP/IP link the specified protocol is used. Valid protocol
266 specifiers are A, B, and C.
267 Protocol A: write IO is reported as completed, if it has reached local
269 disk and local TCP send buffer.
270 Protocol B: write IO is reported as completed, if it has reached local
272 disk and remote buffer cache.
273 Protocol C: write IO is reported as completed, if it has reached both
275 local and remote disk.
276 -c, --connect-int time
278 In case it is not possible to connect to the remote DRBD device
279 immediately, DRBD keeps on trying to connect. With this option you
280 can set the time between two retries. The default value is 10
281 seconds, the unit is 1 second.
282 -i, --ping-int time
284 If the TCP/IP connection linking a DRBD device pair is idle for
285 more than time seconds, DRBD will generate a keep-alive packet to
286 check if its partner is still alive. The default value is 10
287 seconds, the unit is 1 second.
288 -t, --timeout val
290 If the partner node fails to send an expected response packet
291 within val tenths of a second, the partner node is considered dead
292 and therefore the TCP/IP connection is abandoned. The default value
293 is 60 (= 6 seconds).
294 -S, --sndbuf-size size
296 The socket send buffer is used to store packets sent to the
297 secondary node, which are not yet acknowledged (from a network
298 point of view) by the secondary node. When using protocol A, it
299 might be necessary to increase the size of this data structure in
300 order to increase asynchronicity between primary and secondary
301 nodes. But keep in mind that more asynchronicity is synonymous with
302 more data loss in the case of a primary node failure. Since 8.0.13
303 resp. 8.2.7 setting the size value to 0 means that the kernel
304 should autotune this. The default size is 0, i.e. autotune.
305 -r, --rcvbuf-size size
307 Packets received from the network are stored in the socket receive
308 buffer first. From there they are consumed by DRBD. Before 8.3.2
309 the receive buffer's size was always set to the size of the socket
310 send buffer. Since 8.3.2 they can be tuned independently. A value
311 of 0 means that the kernel should autotune this. The default size
312 is 0, i.e. autotune.
313 -k, --ko-count count
315 In case the secondary node fails to complete a single write request
316 for count times the timeout, it is expelled from the cluster, i.e.
317 the primary node goes into StandAlone mode. To disable this
318 feature, you should explicitly set it to 0; defaults may change
319 between versions.
320 -e, --max-epoch-size val
322 With this option the maximal number of write requests between two
323 barriers is limited. Typically set to the same as --max-buffers, or
324 the allowed maximum. Values smaller than 10 can lead to degraded
325 performance. The default value is 2048.
326 -b, --max-buffers val
328 With this option the maximal number of buffer pages allocated by
329 DRBD's receiver thread is limited. Typically set to the same as
330 --max-epoch-size. Small values could lead to degraded performance.
331 The default value is 2048, the minimum 32. Increase this if you
332 cannot saturate the IO backend of the receiving side during linear
333 write or during resync while otherwise idle.
334 See also drbd.conf(5)
336 -u, --unplug-watermark val
338 This setting has no effect with recent kernels that use explicit
339 on-stack plugging (upstream Linux kernel 2.6.39, distributions may
340 have backported).
341 When the number of pending write requests on the standby
343 (secondary) node exceeds the unplug-watermark, we trigger the
344 request processing of our backing storage device. Some storage
345 controllers deliver better performance with small values, others
346 deliver best performance when the value is set to the same value as
347 max-buffers, yet others don't feel much effect at all. Minimum 16,
348 default 128, maximum 131072.
349 -m, --allow-two-primaries
351 With this option set you may assign primary role to both nodes. You
352 only should use this option if you use a shared storage file system
353 on top of DRBD. At the time of writing the only ones are: OCFS2 and
354 GFS. If you use this option with any other file system, you are
355 going to crash your nodes and to corrupt your data!
356 -a, --cram-hmac-alg alg
358 You need to specify the HMAC algorithm to enable peer
359 authentication at all. You are strongly encouraged to use peer
360 authentication. The HMAC algorithm will be used for the challenge
361 response authentication of the peer. You may specify any digest
362 algorithm that is named in /proc/crypto.
363 -x, --shared-secret secret
365 The shared secret used in peer authentication. May be up to 64
366 characters.
367 -A, --after-sb-0pri asb-0p-policy
369 possible policies are:
370 disconnect
372 No automatic resynchronization, simply disconnect.
373 discard-younger-primary
375 Auto sync from the node that was primary before the split-brain
376 situation occurred.
377 discard-older-primary
379 Auto sync from the node that became primary as second during
380 the split-brain situation.
381 discard-zero-changes
383 In case one node did not write anything since the split brain
384 became evident, sync from the node that wrote something to the
385 node that did not write anything. In case none wrote anything
386 this policy uses a random decision to perform a "resync" of 0
387 blocks. In case both have written something this policy
388 disconnects the nodes.
389 discard-least-changes
391 Auto sync from the node that touched more blocks during the
392 split brain situation.
393 discard-node-NODENAME
395 Auto sync to the named node.
396 -B, --after-sb-1pri asb-1p-policy
398 possible policies are:
399 disconnect
401 No automatic resynchronization, simply disconnect.
402 consensus
404 Discard the version of the secondary if the outcome of the
405 after-sb-0pri algorithm would also destroy the current
406 secondary's data. Otherwise disconnect.
407 discard-secondary
409 Discard the secondary's version.
410 call-pri-lost-after-sb
412 Always honor the outcome of the after-sb-0pri algorithm. In
413 case it decides the current secondary has the correct data,
414 call the pri-lost-after-sb on the current primary.
415 violently-as0p
417 Always honor the outcome of the after-sb-0pri algorithm. In
418 case it decides the current secondary has the correct data,
419 accept a possible instantaneous change of the primary's data.
420 -C, --after-sb-2pri asb-2p-policy
422 possible policies are:
423 disconnect
425 No automatic resynchronization, simply disconnect.
426 call-pri-lost-after-sb
428 Always honor the outcome of the after-sb-0pri algorithm. In
429 case it decides the current secondary has the right data, call
430 the pri-lost-after-sb on the current primary.
431 violently-as0p
433 Always honor the outcome of the after-sb-0pri algorithm. In
434 case it decides the current secondary has the right data,
435 accept a possible instantaneous change of the primary's data.
436 -P, --always-asbp
438 Normally the automatic after-split-brain policies are only used if
439 current states of the UUIDs do not indicate the presence of a third
440 node.
441 With this option you request that the automatic after-split-brain
443 policies are used as long as the data sets of the nodes are somehow
444 related. This might cause a full sync, if the UUIDs indicate the
445 presence of a third node. (Or double faults have led to strange
446 UUID sets.)
447 -R, --rr-conflict role-resync-conflict-policy
449 This option sets DRBD's behavior when DRBD deduces from its meta
450 data that a resynchronization is needed, and the SyncTarget node is
451 already primary. The possible settings are: disconnect,
452 call-pri-lost and violently. While disconnect speaks for itself,
453 with the call-pri-lost setting the pri-lost handler is called which
454 is expected to either change the role of the node to secondary, or
455 remove the node from the cluster. The default is disconnect.
456 With the violently setting you allow DRBD to force a primary node
458 into SyncTarget state. This means that the data exposed by DRBD
459 changes to the SyncSource's version of the data instantaneously.
460 USE THIS OPTION ONLY IF YOU KNOW WHAT YOU ARE DOING.
461 -d, --data-integrity-alg hash_alg
463 DRBD can ensure the data integrity of the user's data on the
464 network by comparing hash values. Normally this is ensured by the
465 16 bit checksums in the headers of TCP/IP packets. This option can
466 be set to any of the kernel's data digest algorithms. In a typical
467 kernel configuration you should have at least one of md5, sha1, and
468 crc32c available. By default this is not enabled.
469 See also the notes on data integrity on the drbd.conf manpage.
471 -o, --no-tcp-cork
473 DRBD usually uses the TCP socket option TCP_CORK to hint to the
474 network stack when it can expect more data, and when it should
475 flush out what it has in its send queue. There is at least one
476 network stack that performs worse when one uses this hinting
477 method. Therefore we introduced this option, which disable the
478 setting and clearing of the TCP_CORK socket option by DRBD.
479 -p, --ping-timeout ping_timeout
481 The time the peer has to answer to a keep-alive packet. In case the
482 peer's reply is not received within this time period, it is
483 considered dead. The default unit is tenths of a second, the
484 default value is 5 (for half a second).
485 -D, --discard-my-data
487 Use this option to manually recover from a split-brain situation.
488 In case you do not have any automatic after-split-brain policies
489 selected, the nodes refuse to connect. By passing this option you
490 make this node a sync target immediately after successful connect.
491 -n, --dry-run
493 Causes DRBD to abort the connection process after the resync
494 handshake, i.e. no resync gets performed. You can find out which
495 resync DRBD would perform by looking at the kernel's log file.
496 -g, --on-congestion congestion_policy, -f, --congestion-fill
498 fill_threshold, -h, --congestion-extents active_extents_threshold
499 By default DRBD blocks when the available TCP send queue becomes
500 full. That means it will slow down the application that generates
501 the write requests that cause DRBD to send more data down that TCP
502 connection.
503 When DRBD is deployed with DRBD-proxy it might be more desirable
505 that DRBD goes into AHEAD/BEHIND mode shortly before the send queue
506 becomes full. In AHEAD/BEHIND mode DRBD does no longer replicate
507 data, but still keeps the connection open.
508 The advantage of the AHEAD/BEHIND mode is that the application is
510 not slowed down, even if DRBD-proxy's buffer is not sufficient to
511 buffer all write requests. The downside is that the peer node falls
512 behind, and that a resync will be necessary to bring it back into
513 sync. During that resync the peer node will have an inconsistent
514 disk.
515 Available congestion_policys are block and pull-ahead. The default
517 is block. Fill_threshold might be in the range of 0 to 10GiBytes.
518 The default is 0 which disables the check.
519 Active_extents_threshold has the same limits as al-extents.
520 The AHEAD/BEHIND mode and its settings are available since DRBD
522 8.3.10.
523 syncer
525 Changes the synchronization daemon parameters of device at runtime.
526 -r, --rate rate
528 To ensure smooth operation of the application on top of DRBD, it is
529 possible to limit the bandwidth that may be used by background
530 synchronization. The default is 250 KiB/sec, the default unit is
531 KiB/sec.
532 -a, --after minor
534 Start resync on this device only if the device with minor is
535 already in connected state. Otherwise this device waits in
536 SyncPause state.
537 -e, --al-extents extents
539 DRBD automatically performs hot area detection. With this parameter
540 you control how big the hot area (=active set) can get. Each extent
541 marks 4M of the backing storage. In case a primary node leaves the
542 cluster unexpectedly, the areas covered by the active set must be
543 resynced upon rejoining of the failed node. The data structure is
544 stored in the meta-data area, therefore each change of the active
545 set is a write operation to the meta-data device. A higher number
546 of extents gives longer resync times but less updates to the
547 meta-data. The default number of extents is 127. (Minimum: 7,
548 Maximum: 3843)
549 -v, --verify-alg hash-alg
551 During online verification (as initiated by the verify
552 sub-command), rather than doing a bit-wise comparison, DRBD applies
553 a hash function to the contents of every block being verified, and
554 compares that hash with the peer. This option defines the hash
555 algorithm being used for that purpose. It can be set to any of the
556 kernel's data digest algorithms. In a typical kernel configuration
557 you should have at least one of md5, sha1, and crc32c available. By
558 default this is not enabled; you must set this option explicitly in
559 order to be able to use on-line device verification.
560 See also the notes on data integrity on the drbd.conf manpage.
562 -c, --cpu-mask cpu-mask
564 Sets the cpu-affinity-mask for DRBD's kernel threads of this
565 device. The default value of cpu-mask is 0, which means that DRBD's
566 kernel threads should be spread over all CPUs of the machine. This
567 value must be given in hexadecimal notation. If it is too big it
568 will be truncated.
569 -C, --csums-alg hash-alg
571 A resync process sends all marked data blocks form the source to
572 the destination node, as long as no csums-alg is given. When one is
573 specified the resync process exchanges hash values of all marked
574 blocks first, and sends only those data blocks over, that have
575 different hash values.
576 This setting is useful for DRBD setups with low bandwidth links.
578 During the restart of a crashed primary node, all blocks covered by
579 the activity log are marked for resync. But a large part of those
580 will actually be still in sync, therefore using csums-alg will
581 lower the required bandwidth in exchange for CPU cycles.
582 -R, --use-rle
584 During resync-handshake, the dirty-bitmaps of the nodes are
585 exchanged and merged (using bit-or), so the nodes will have the
586 same understanding of which blocks are dirty. On large devices, the
587 fine grained dirty-bitmap can become large as well, and the bitmap
588 exchange can take quite some time on low-bandwidth links.
589 Because the bitmap typically contains compact areas where all bits
591 are unset (clean) or set (dirty), a simple run-length encoding
592 scheme can considerably reduce the network traffic necessary for
593 the bitmap exchange.
594 For backward compatibilty reasons, and because on fast links this
596 possibly does not improve transfer time but consumes cpu cycles,
597 this defaults to off.
598 Introduced in 8.3.2.
600 -p, --c-plan-ahead plan_time, -s, --c-fill-target fill_target, -d,
602 --c-delay-target delay_target, -M, --c-max-rate max_rate
603 The dynamic resync speed controller gets enabled with setting
604 plan_time to a positive value. It aims to fill the buffers along
605 the data path with either a constant amount of data fill_target, or
606 aims to have a constant delay time of delay_target along the path.
607 The controller has an upper bound of max_rate.
608 By plan_time the agility of the controller is configured. Higher
610 values yield for slower/lower responses of the controller to
611 deviation from the target value. It should be at least 5 times RTT.
612 For regular data paths a fill_target in the area of 4k to 100k is
613 appropriate. For a setup that contains drbd-proxy it is advisable
614 to use delay_target instead. Only when fill_target is set to 0 the
615 controller will use delay_target. 5 times RTT is a reasonable
616 starting value. Max_rate should be set to the bandwidth available
617 between the DRBD-hosts and the machines hosting DRBD-proxy, or to
618 the available disk-bandwidth.
619 The default value of plan_time is 0, the default unit is 0.1
621 seconds. Fill_target has 0 and sectors as default unit.
622 Delay_target has 1 (100ms) and 0.1 as default unit. Max_rate has
623 10240 (100MiB/s) and KiB/s as default unit.
624 -m, --c-min-rate min_rate
626 We track the disk IO rate caused by the resync, so we can detect
627 non-resync IO on the lower level device. If the lower level device
628 seems to be busy, and the current resync rate is above min_rate, we
629 throttle the resync.
630 The default value of min_rate is 4M, the default unit is k. If you
632 want to not throttle at all, set it to zero, if you want to
633 throttle always, set it to one.
634 -n, --on-no-data-accessible ond-policy
636 This setting controls what happens to IO requests on a degraded,
637 disk less node (I.e. no data store is reachable). The available
638 policies are io-error and suspend-io.
639 If ond-policy is set to suspend-io you can either resume IO by
641 attaching/connecting the last lost data storage, or by the drbdadm
642 resume-io res command. The latter will result in IO errors of
643 course.
644 The default is io-error. This setting is available since DRBD
646 8.3.9.
647 primary
649 Sets the device into primary role. This means that applications (e.g. a
650 file system) may open the device for read and write access. Data
651 written to the device in primary role are mirrored to the device in
652 secondary role.
653 Normally it is not possible to set both devices of a connected DRBD
655 device pair to primary role. By using the --allow-two-primaries option,
656 you override this behavior and instruct DRBD to allow two primaries.
657 -o, --overwrite-data-of-peer
659 Alias for --force.
660 -f, --force
662 Becoming primary fails if the local replica is not up-to-date. I.e.
663 when it is inconsistent, outdated of consistent. By using this
664 option you can force it into primary role anyway. USE THIS OPTION
665 ONLY IF YOU KNOW WHAT YOU ARE DOING.
666 secondary
668 Brings the device into secondary role. This operation fails as long as
669 at least one application (or file system) has opened the device.
670 It is possible that both devices of a connected DRBD device pair are
672 secondary.
673 verify
675 This initiates on-line device verification. During on-line
676 verification, the contents of every block on the local node are
677 compared to those on the peer node. Device verification progress can be
678 monitored via /proc/drbd. Any blocks whose content differs from that of
679 the corresponding block on the peer node will be marked out-of-sync in
680 DRBD's on-disk bitmap; they are not brought back in sync automatically.
681 To do that, simply disconnect and reconnect the resource.
682 If on-line verification is already in progress (and this node is
684 "VerifyS"), this command silently "succeeds". In this case, any
685 start-sector (see below) will be ignored, and any stop-sector (see
686 below) will be honored. This can be used to stop a running verify, or
687 to update/shorten/extend the coverage of the currently running verify.
688 This command will fail if the device is not part of a connected device
690 pair.
691 See also the notes on data integrity on the drbd.conf manpage.
693 -s, --start start-sector
695 Since version 8.3.2, on-line verification should resume from the
696 last position after connection loss. It may also be started from an
697 arbitrary position by setting this option. If you had reached some
698 stop-sector before, and you do not specify an explicit
699 start-sector, verify should resume from the previous stop-sector.
700 Default unit is sectors. You may also specify a unit explicitly.
702 The start-sector will be rounded down to a multiple of 8 sectors
703 (4kB).
704 -S, --stop stop-sector
706 Since version 8.3.14, on-line verification can be stopped before it
707 reaches end-of-device. This can be
708 Default unit is sectors. You may also specify a unit explicitly.
710 The stop-sector may be updated by issuing an additional drbdsetup
711 verify command on the same node while the verify is running.
712 invalidate
714 This forces the local device of a pair of connected DRBD devices into
715 SyncTarget state, which means that all data blocks of the device are
716 copied over from the peer.
717 This command will fail if the device is not either part of a connected
719 device pair, or disconnected Secondary.
720 invalidate-remote
722 This forces the local device of a pair of connected DRBD devices into
723 SyncSource state, which means that all data blocks of the device are
724 copied to the peer.
725 On a disconnected Primary device, this will set all bits in the out of
727 sync bitmap. As a side affect this suspends updates to the on disk
728 activity log. Updates to the on disk activity log resume automatically
729 when necessary.
730 wait-connect
732 Returns as soon as the device can communicate with its partner device.
733 -t, --wfc-timeout wfc_timeout, -d, --degr-wfc-timeout degr_wfc_timeout,
735 -o, --outdated-wfc-timeout outdated_wfc_timeout, -w, --wait-after-sb
736 This command will fail if the device cannot communicate with its
737 partner for timeout seconds. If the peer was working before this
738 node was rebooted, the wfc_timeout is used. If the peer was already
739 down before this node was rebooted, the degr_wfc_timeout is used.
740 If the peer was sucessfully outdated before this node was rebooted
741 the outdated_wfc_timeout is used. The default value for all those
742 timeout values is 0 which means to wait forever. In case the
743 connection status goes down to StandAlone because the peer appeared
744 but the devices had a split brain situation, the default for the
745 command is to terminate. You can change this behavior with the
746 --wait-after-sb option.
747 wait-sync
749 Returns as soon as the device leaves any synchronization into connected
750 state. The options are the same as with the wait-connect command.
751 disconnect
753 Removes the information set by the net command from the device. This
754 means that the device goes into unconnected state and will no longer
755 listen for incoming connections.
756 detach
758 Removes the information set by the disk command from the device. This
759 means that the device is detached from its backing storage device.
760 -f, --force
762 A regular detach returns after the disk state finally reached
763 diskless. As a consequence detaching from a frozen backing block
764 device never terminates.
765 On the other hand A forced detach returns immediately. It allows
767 you to detach DRBD from a frozen backing block device. Please note
768 that the disk will be marked as failed until all pending IO
769 requests where finished by the backing block device.
770 down
772 Removes all configuration information from the device and forces it
773 back to unconfigured state.
774 role
776 Shows the current roles of the device and its peer, as local/peer.
777 state
779 Deprecated alias for "role"
780 cstate
782 Shows the current connection state of the device.
783 dstate
785 Shows the current states of the backing storage devices, as local/peer.
786 status
788 Shows the current status of the device in XML-like format. Example
789 output:
790 <resource minor="0" name="s0" cs="SyncTarget" st1="Secondary" st2="Secondary"
792 ds1="Inconsistent" ds2="UpToDate" resynced_precent="5.9" />
793 resize
796 This causes DRBD to reexamine the size of the device's backing storage
797 device. To actually do online growing you need to extend the backing
798 storages on both devices and call the resize command on one of your
799 nodes.
800 The --assume-peer-has-space allows you to resize a device which is
802 currently not connected to the peer. Use with care, since if you do not
803 resize the peer's disk as well, further connect attempts of the two
804 will fail.
805 When the --assume-clean option is given DRBD will skip the resync of
807 the new storage. Only do this if you know that the new storage was
808 initialized to the same content by other means.
809 check-resize
811 To enable DRBD to detect offline resizing of backing devices this
812 command may be used to record the current size of backing devices. The
813 size is stored in files in /var/lib/drbd/ named drbd-minor-??.lkbd
814 This command is called by drbdadm resize res after drbdsetup device
816 resize returned.
817 pause-sync
819 Temporarily suspend an ongoing resynchronization by setting the local
820 pause flag. Resync only progresses if neither the local nor the remote
821 pause flag is set. It might be desirable to postpone DRBD's
822 resynchronization after eventual resynchronization of the backing
823 storage's RAID setup.
824 resume-sync
826 Unset the local sync pause flag.
827 outdate
829 Mark the data on the local backing storage as outdated. An outdated
830 device refuses to become primary. This is used in conjunction with
831 fencing and by the peer's fence-peer handler.
832 show-gi
834 Displays the device's data generation identifiers verbosely.
835 get-gi
837 Displays the device's data generation identifiers.
838 show
840 Shows all available configuration information of the device.
841 suspend-io
843 This command is of no apparent use and just provided for the sake of
844 completeness.
845 resume-io
847 If the fence-peer handler fails to stonith the peer node, and your
848 fencing policy is set to resource-and-stonith, you can unfreeze IO
849 operations with this command.
850 events
852 Displays every state change of DRBD and all calls to helper programs.
853 This might be used to get notified of DRBD's state changes by piping
854 the output to another program.
855 -a, --all-devices
857 Display the events of all DRBD minors.
858 -u, --unfiltered
860 This is a debugging aid that displays the content of all received
861 netlink messages.
862 new-current-uuid
864 Generates a new current UUID and rotates all other UUID values. This
865 has at least two use cases, namely to skip the initial sync, and to
866 reduce network bandwidth when starting in a single node configuration
867 and then later (re-)integrating a remote site.
868 Available option:
870 -c, --clear-bitmap
872 Clears the sync bitmap in addition to generating a new current
873 UUID.
874 This can be used to skip the initial sync, if you want to start from
876 scratch. This use-case does only work on "Just Created" meta data.
877 Necessary steps:
878 1. On both nodes, initialize meta data and configure the device.
880 drbdadm -- --force create-md res
882 2. They need to do the initial handshake, so they know their sizes.
884 drbdadm up res
886 3. They are now Connected Secondary/Secondary
888 Inconsistent/Inconsistent. Generate a new current-uuid and clear
889 the dirty bitmap.
890 drbdadm -- --clear-bitmap new-current-uuid res
892 4. They are now Connected Secondary/Secondary UpToDate/UpToDate. Make
894 one side primary and create a file system.
895 drbdadm primary res
897 mkfs -t fs-type $(drbdadm sh-dev res)
899 One obvious side-effect is that the replica is full of old garbage
901 (unless you made them identical using other means), so any
902 online-verify is expected to find any number of out-of-sync blocks.
903 You must not use this on pre-existing data! Even though it may appear
905 to work at first glance, once you switch to the other node, your data
906 is toast, as it never got replicated. So do not leave out the mkfs (or
907 equivalent).
908 This can also be used to shorten the initial resync of a cluster where
910 the second node is added after the first node is gone into production,
911 by means of disk shipping. This use-case works on disconnected devices
912 only, the device may be in primary or secondary role.
913 The necessary steps on the current active server are:
915 1. drbdsetup device new-current-uuid --clear-bitmap
917 2. Take the copy of the current active server. E.g. by pulling a disk
919 out of the RAID1 controller, or by copying with dd. You need to
920 copy the actual data, and the meta data.
921 3. drbdsetup device new-current-uuid
923 Now add the disk to the new secondary node, and join it to the cluster.
925 You will get a resync of that parts that were changed since the first
926 call to drbdsetup in step 1.
927
929 For examples, please have a look at the DRBD User's Guide[1].
930
932 This document was revised for version 8.3.2 of the DRBD distribution.
933
935 Written by Philipp Reisner <philipp.reisner@linbit.com> and Lars
936 Ellenberg <lars.ellenberg@linbit.com>
937
939 Report bugs to <drbd-user@lists.linbit.com>.
940
942 Copyright 2001-2008 LINBIT Information Technologies, Philipp Reisner,
943 Lars Ellenberg. This is free software; see the source for copying
944 conditions. There is NO warranty; not even for MERCHANTABILITY or
945 FITNESS FOR A PARTICULAR PURPOSE.
946
948 drbd.conf(5), drbd(8), drbddisk(8), drbdadm(8), DRBD User's Guide[1],
949 DRBD web site[2]
950
952 1. DRBD User's Guide
953 http://www.drbd.org/users-guide/
954 2. DRBD web site
956 http://www.drbd.org/
957DRBD 8.3.2 5 Dec 2008 DRBDSETUP(8)