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Runbook for Creating the Solaris Volume Manager Software State Database

In runbooks, the following disk names are assumed.

primary mirror c0t0d0
secondary mirror c0t1d0
backup system disk c0t2d0
hot spare disk c0t3d0

These names are placeholders for the real disk names. In most cases, the logical disk names will be different.

As a first step for each of the presented configurations, the Solaris Volume Manager software state database replicas must be created. Providing more than one replica protects the configuration against losing the definition of the volumes.

Solaris Volume Manager software has the following behavior with respect to loss of replicas:

  • The system panics when more than half of the replicas break.

  • The system does not boot unless more than half of the replicas are available. The system administrator must remove broken replicas in single-user mode to restore the majority.

Ideally, three replicas are created, each on a different disk, connected to a different host bus adapter. In this runbook, we assume that only the system disks are under control of Solaris Volume Manager software, and this ideal replica configuration is not always possible.

Be aware that the optimal replica configuration may be different from the one presented here, in the case that the data disks are also under control of Solaris Volume Manager software and can contain state database replicas.

Replica creation for the two-disk configuration (and disabling the quorum rule).

metadb -a -f -c 2 c0t0d0s7
 metadb -a -c 2 c0t1d0s7
 echo set md:mirrored_root_flag=1 >> /etc/system

Replica creation for the three-disk and four-disk configuration. (Do not create unnecessary multiple copies per disk.)

metadb -a -f c0t0d0s7
metadb -a   c0t1d0s7
metadb -a   c0t2d0s7

Runbook for the Two-Disk Configuration

Copy the VTOC to the mirror disk. It is not necessary to make this disk bootable because the bootblock from the first submirror is copied to the second submirror during the resync operation. Use the prtvtoc command as follows.

prtvtoc /dev/rdsk/c0t0d0s2 | fmthard -s - /dev/rdsk/c0t1d0s2

Create the state database replicas as described in the previous runbook.

Create the volumes, as follows.

metainit -f d10 1 1 c0t0d0s0
metainit -f d11 1 1 c0t0d0s1
metainit -f d13 1 1 c0t0d0s3
 
metainit d20 1 1 c0t1d0s0
metainit d21 1 1 c0t1d0s1
metainit d23 1 1 c0t1d0s3

metainit d0 -m d10
metainit d1 -m d11
metainit d3 -m d13

Make the system boot from the mirror, as follows.

metaroot d0

Replace the remaining partitions with volumes in /etc/vfstab, as follows.

cp /etc/vfstab /etc/vfstab.tmp
 cat /etc/vfstab.tmp | \
   sed s,/dev/dsk/c0t0d0s1,/dev/md/dsk/d1, | \
   sed s,/dev/dsk/c0t0d0s3,/dev/md/dsk/d3, | \ 
   sed s,/dev/rdsk/c0t0d0s3,/dev/md/rdsk/d3, > /etc/vfstab

Document the physical device name of the two disks in the mirror, as shown in the underlined portion of the following example for the disk c0t1d0.

ls -l /dev/rdsk/c0t1d0s0
lrwxrwxrwx  1 root  other  68 Nov 30 15:43 /dev/rdsk/c0t1d0s0 -> 
../../devices/ssm@0,0/pci@18,700000/pci@2/SUNW,isptwo@4/sd@1,0:a,raw

Halt the system, as follows.

init 0

Create an OBP alias for the bootable disks. Beware that for disks on certain controllers, the sd driver name must be replaced by disk. Verify this, using the OBP show-disks command before entering the nvalias commands.

ok nvalias bootdisk /ssm@0,0/pci@18,700000/pci@2/SUNW,isptwo@4/sd@0,0:a
ok nvalias mirrdisk /ssm@0,0/pci@18,700000/pci@2/SUNW,isptwo@4/sd@1,0:a
ok setenv boot-device bootdisk mirrdisk
ok boot

Attach the submirrors, as follows.

metattach d0 d20
metattach d1 d21
metattach d3 d23

Runbook for the Three-Disk Configuration

Copy the VTOC and the boot block to the contingency disk, as shown here.

prtvtoc /dev/rdsk/c0t0d0s2| fmthard -s - /dev/rdsk/c0t2d0s2
/usr/sbin/installboot /usr/platform/´uname -i´/lib/fs/ufs/bootblk 
/dev/rdsk/c0t2d0s2

Create the state databases and volumes as described in the runbook for the two-disk configuration.

Perform a full backup of the file systems to the backup system disk and modify system files so that the disk becomes bootable from partitions.

newfs /dev/rdsk/c0t2d0s0
mount /dev/dsk/c0t2d0s0 /mnt
ufsdump 0f - / | (cd /mnt; ufsrestore rf - )
cat /etc/vfstab | \
   sed s,/dev/md/dsk/d0,/dev/dsk/c0t2d0s0, | \
   sed s,/dev/md/dsk/d1,/dev/dsk/c0t2d0s1, | \
   sed s,/dev/md/dsk/d3,/dev/dsk/c0t2d0s3, | \
   sed s,/dev/md/rdsk/d0,/dev/rdsk/c0t2d0s0, | \
   sed s,/dev/md/rdsk/d1,/dev/rdsk/c0t2d0s1, | \
   sed s,/dev/md/rdsk/d3,/dev/rdsk/c0t2d0s3, > /mnt/etc/vfstab
 cat /etc/system | grep -v rootdev > /mnt/etc/system
 umount /mnt

 newfs /dev/rdsk/c0t2d0s3
 mount /dev/dsk/c0t2d0s3 /mnt
 ufsdump 0f - /var | (cd /mnt; ufsrestore rf - )
 umount /mnt

Put the preceding commands in a script /usr/local/system-backup, make the script executable, and execute from cron, as shown here. Note that this is the most rudimentary implementation. You may want to refine this by using a combination of full and incremental ufsdump and more sophisticated update schemes.

10 1 * * 0  /usr/local/system-backup

Create an OBP alias for the contingency disk, as described earlier.

Runbook for the Four-Disk Configuration

Copy the VTOC and boot block to the fourth disk. This disk must also be made bootable for the unlikely situation that the hot spare actually kicks in and later becomes the only surviving disk in the mirror.

prtvtoc /dev/rdsk/c0t0d0s2| fmthard -s - /dev/rdsk/c0t3d0s2
/usr/sbin/installboot /usr/platform/´uname -i´/lib/fs/ufs/bootblk 
/dev/rdsk/c0t3d0s2

Create the state database replicas and volumes, configure the contingency disk as described in the previous runbook.

Configure the hot spare pools. Each mirror gets its own hot spare pool with a partition of the corresponding size, as follows. Putting all spare partitions in the same pool is simpler, but correct behavior then depends on the order of the partitions in the pool.

metahs -a hsp000 c0t3d0s0
metaparam -h hsp000 d10
metaparam -h hsp000 d20
 
metahs -a hsp001 c0t3d0s1
metaparam -h hsp001 d11
metaparam -h hsp001 d21
 
metahs -a hsp003 c0t3d0s3
metaparam -h hsp003 d13
metaparam -h hsp003 d23

Use of the SUNBEsdm Package

With this article, we provide the SUNBEsdm package. The package contains a script sdmsetup that greatly reduces the manual work to implement the runbooks mentioned in this article. The SUNBEsdm package is not supported by Sun, and is only provided, here, to demonstrate our example.

Take care to minimize the risk of running the script sdmsetup. This script does not modify your system, but rather generates the commands to be executed, allowing for inspection prior to execution.

The prerequisites for sdmsetup are as follows:

  • Solstice DiskSuite 4.2.1 software must be installed.

  • No state database or volume must already exist.

  • A free slice must exist to be used as state database.

  • A free slice must exist to be used as dump device (optional).

  • All currently mounted file systems must correspond to entries in /etc/vfstab.

  • All used disks must be of the same geometry.

  • Slice 2 on all disks must cover the entire disk.

A README file in the package contains detailed instructions for the usage of the script.

Ordering Sun Documents

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Accessing Sun Documentation Online

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To reference Sun BluePrints OnLine articles, visit the Sun BluePrints OnLine Web site at: http://www.sun.com/blueprints/online.html

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