1md.tab(4) File Formats md.tab(4)
2
6 md.tab, md.cf - Solaris Volume Manager utility files
7
9 /etc/lvm/md.tab
10 /etc/lvm/md.cf
11
14 The file /etc/lvm/md.tab can be used by metainit(1M) and metadb(1M) to
15 configure metadevices, hot spare pools, and metadevice state database
16 replicas in a batch-like mode. Solaris Volume Manager does not store
17 configuration information in the /etc/lvm/md.tab file. You can use:
18 metastat -p > /etc/lvm/md.tab
20 to create this file. Edit it by hand using the instructions in the
25 md.tab.4 file. Similarly, if no hot spares are in use, the cp md.cf
26 md.tab command generates an acceptable version of the md.tab file, with
27 the editing caveats previously mentioned.
28 When using the md.tab file, each metadevice, hot spare pool, or state
31 database replica in the file must have a unique entry. Entries can
32 include the following: simple metadevices (stripes, concatenations, and
33 concatenations of stripes); mirrors, soft partitions, and RAID5 metade‐
34 vices; hot spare pools; and state database replicas. Because md.tab
35 contains only entries that you enter in it, do not rely on the file for
36 the current configuration of metadevices, hot spare pools, and replicas
37 on the system at any given time.
38 Tabs, spaces, comments (by using a pound sign, #), and continuation of
41 lines (by using a backslash-newline), are allowed.
42 Typically, you set up metadevices according to information specified on
45 the command line by using the metainit command. Likewise, you set up
46 state database replicas with the metadb command.
47 An alternative to the command line is to use the md.tab file. Metade‐
50 vices and state database replicas can be specified in the md.tab file
51 in any order, and then activated in a batch-like mode with the metainit
52 and metadb commands.
53 If you edit the md.tab file, you specify one complete configuration
56 entry per line. Metadevices are defined using the same syntax as
57 required by the metainit command. You then run the metainit command
58 with either the -a option, to activate all metadevices in the md.tab
59 file, or with the metadevice name corresponding to a specific configu‐
60 ration entry.
61 metainit does not maintain the state of the volumes that would have
64 been created when metainit is run with both the -a and -n flags. If a
65 device d0 is created in the first line of the md.tab file, and a later
66 line in md.tab assumes the existence of d0, the later line will fail
67 when metainit -an runs (even if it would succeed with metainit -a).
68 State database replicas are defined in the /etc/lvm/md.tab file as fol‐
71 lows: mddb number options [ slice... ] Where mddb number is the charac‐
72 ters mddb followed by a number of two or more digits that identifies
73 the state database replica. slice is a physical slice. For example:
74 mddb05 /dev/dsk/c0t1d0s2. The file /etc/lvm/md.cf is a backup of the
75 configuration used for disaster recovery. Whenever the Volume Manager
76 configuration is changed, this file is automatically updated (except
77 when hot sparing occurs). You should not directly edit this file.
78
80 Example 1 Concatenation
81 All drives in the following examples have the same size of 525 Mbytes.
84 This example shows a metadevice, /dev/md/dsk/d7, consisting of a con‐
88 catenation of four disks.
89 #
92 # (concatenation of four disks)
93 #
94 d7 4 1 c0t1d0s0 1 c0t2d0s0 1 c0t3d0s0 1 c0t4d0s0
95 The number 4 indicates there are four individual stripes in the con‐
99 catenation. Each stripe is made of one slice, hence the number 1
100 appears in front of each slice. Note that the first disk sector in all
101 of the above devices contains a disk label. To preserve the labels on
102 devices /dev/dsk/c0t2d0s0, /dev/dsk/c0t3d0s0, and /dev/dsk/c0t4d0s0,
103 the metadisk driver must skip at least the first sector of those disks
104 when mapping accesses across the concatenation boundaries. Since skip‐
105 ping only the first sector would create an irregular disk geometry, the
106 entire first cylinder of these disks will be skipped. This allows
107 higher level file system software to optimize block allocations cor‐
108 rectly.
109 Example 2 Stripe
112 This example shows a metadevice, /dev/md/dsk/d15, consisting of two
115 slices.
116 #
119 # (stripe consisting of two disks)
120 #
121 d15 1 2 c0t1d0s2 c0t2d0s2 -i 32k
122 The number 1 indicates that one stripe is being created. Because the
126 stripe is made of two slices, the number 2 follows next. The optional
127 -i followed by 32k specifies the interlace size will be 32 Kbytes. If
128 the interlace size were not specified, the stripe would use the default
129 value of 16 Kbytes.
130 Example 3 Concatenation of Stripes
133 This example shows a metadevice, /dev/md/dsk/d75, consisting of a con‐
136 catenation of two stripes of three disks.
137 #
140 # (concatenation of two stripes, each consisting of three disks)
141 #
142 d75 2 3 c0t1d0s2 c0t2d0s2 c0t3d0s2 -i 16k \
143 3 c1t1d0s2 c1t2d0s2 c1t3d0s2 -i 32k
144 On the first line, the -i followed by 16k specifies that the stripe's
148 interlace size is 16 Kbytes. The second set specifies the stripe inter‐
149 lace size will be 32 Kbytes. If the second set did not specify 32
150 Kbytes, the set would use default interlace value of 16 Kbytes. The
151 blocks of each set of three disks are interlaced across three disks.
152 Example 4 Mirroring
155 This example shows a three-way mirror, /dev/md/dsk/d50, consisting of
158 three submirrors. This mirror does not contain any existing data.
159 #
162 # (mirror)
163 #
164 d50 -m d51
165 d51 1 1 c0t1d0s2
166 d52 1 1 c0t2d0s2
167 d53 1 1 c0t3d0s2
168 In this example, a one-way mirror is first defined using the -m option.
172 The one-way mirror consists of submirror d51. The other two submirrors,
173 d52 and d53, are attached later using the metattach command. The
174 default read and write options in this example are a round-robin read
175 algorithm and parallel writes to all submirrors. The order in which
176 mirrors appear in the /etc/lvm/md.tab file is unimportant.
177 Example 5 RAID5
180 This example shows a RAID5 metadevice, d80, consisting of three slices:
183 #
186 # (RAID devices)
187 #
188 d80 -r c0t1d0s1 c1t0d0s1 c2t0d0s1 -i 20k
189 In this example, a RAID5 metadevice is defined using the -r option with
193 an interlace size of 20 Kbytes. The data and parity segments will be
194 striped across the slices, c0t1d0s1, c1t0d0s1, and c2t0d0s1.
195 Example 6 Soft Partition
198 This example shows a soft partition, d85, that reformats an entire 9 GB
201 disk. Slice 0 occupies all of the disk except for the few Mbytes taken
202 by slice 7, which is space reserved for a state database replica. Slice
203 7 will be a minimum of 4Mbytes, but could be larger, depending on the
204 disk geometry. d85 sits on c3t4d0s0.
205 Drives are repartitioned when they are added to a diskset only if Slice
209 7 is not set up correctly. A small portion of each drive is reserved in
210 Slice 7 for use by Volume Manager. The remainder of the space on each
211 drive is placed into Slice 0. Any existing data on the disks is lost
212 after repartitioning. After adding a drive to a diskset, you can repar‐
213 tition the drive as necessary. However, Slice 7 should not be moved,
214 removed, or overlapped with any other partition.
215 Manually specifying the offsets and extents of soft partitions is not
219 recommended. This example is included for to provide a better under‐
220 standing of the file if it is automatically generated and for complete‐
221 ness.
222 #
225 # (Soft Partitions)
226 d85 -p -e c3t4d0 9g
227 In this example, creating the soft partition and required space for the
231 state database replica occupies all 9 GB of disk c3t4d0.
232 Example 7 Soft Partition
235 This example shows the command used to re-create a soft partition with
238 two extents, the first one starting at offset 20483 and extending for
239 20480 blocks and the second extent starting at 135398 and extending for
240 20480 blocks:
241 #
244 # (Soft Partitions)
245 #
246 d1 -p c0t3d0s0 -o 20483 -b 20480 -o 135398 -b 20480
247 Example 8 Hot Spare
250 This example shows a three-way mirror, /dev/md/dsk/d10, consisting of
253 three submirrors and three hot spare pools.
254 #
257 # (mirror and hot spare)
258 #
259 d10 -m d20
260 d20 1 1 c1t0d0s2 -h hsp001
261 d30 1 1 c2t0d0s2 -h hsp002
262 d40 1 1 c3t0d0s2 -h hsp003
263 hsp001 c2t2d0s2 c3t2d0s2 c1t2d0s2
264 hsp002 c3t2d0s2 c1t2d0s2 c2t2d0s2
265 hsp003 c1t2d0s2 c2t2d0s2 c3t2d0s2
266 In this example, a one-way mirror is first defined using the -m option.
270 The submirrors are attached later using the metattach(1M) command. The
271 hot spare pools to be used are tied to the submirrors with the -h
272 option. In this example, there are three disks used as hot spares,
273 defined in three separate hot spare pools. The hot spare pools are
274 given the names hsp001, hsp002, and hsp003. Setting up three hot spare
275 pools rather than assigning just one hot spare with each component
276 helps to maximize the use of hardware. This configuration enables the
277 user to specify that the most desirable hot spare be selected first,
278 and improves availability by having more hot spares available. At the
279 end of the entry, the hot spares to be used are defined. Note that,
280 when using the md.tab file, to associate hot spares with metadevices,
281 the hot spare spool does not have to exist prior to the association.
282 Volume Manager takes care of the order in which metadevices and hot
283 spares are created when using the md.tab file.
284 Example 9 State Database Replicas
287 This example shows how to set up an initial state database and three
290 replicas on a server that has three disks.
291 #
294 # (state database and replicas)
295 #
296 mddb01 -c 3 c0t1d0s0 c0t2d0s0 c0t3d0s0
297 In this example, three state database replicas are stored on each of
301 the three slices. Once the above entry is made in the /etc/lvm/md.tab
302 file, the metadb command must be run with both the -a and -f options.
303 For example, typing the following command creates one state database
304 replicas on three slices:
305 # metadb -a -f mddb01
308
311 o /etc/lvm/md.tab
312 o /etc/lvm/md.cf
314
316 mdmonitord(1M), metaclear(1M), metadb(1M), metadetach(1M), metahs(1M),
317 metainit(1M), metaoffline(1M), metaonline(1M), metaparam(1M), metare‐
318 cover(1M), metarename(1M), metareplace(1M), metaroot(1M), metas‐
319 sist(1M), metaset(1M), metastat(1M), metasync(1M), metattach(1M),
320 md.cf(4), mddb.cf(4), attributes(5), md(7D)
321 Solaris Volume Manager Administration Guide
324
326 Recursive mirroring is not allowed; that is, a mirror cannot appear in
327 the definition of another mirror.
328 Recursive logging is not allowed.
331 Stripes and RAID5 metadevices must contains slices or soft partitions
334 only.
335 Mirroring of RAID5 metadevices is not allowed.
338 Soft partitions can be built directly on slices or can be the top level
341 (accessible by applications directly), but cannot be in the middle,
342 with other metadevices above and below them.
343
345 Trans metadevices have been replaced by UFS logging. Existing trans
346 devices are not logging--they pass data directly through to the under‐
347 lying device. See mount_ufs(1M) for more information about UFS logging.
348SunOS 5.11 15 Dec 2004 md.tab(4)