DiskMirroring

Using a software mirroring system on Solaris can be brutal. It is prone to configuration error and recovery can be a bitch. My personal point of view is buy as much central storage as you can afford and use a hardware raid, so you don't have to use to disksuite..

Since you are still reading, I guess you haven't splurged on the $50k raid NAS (Network Attached Storage). Let move on.

• DisksuiteLayout - Planning your installation.
• MirrorRaid1 - Good old mirrors.
• MirrorRaid5 - Gobs of disks cobbled together.
• DiskRecovery - Recovering your lost disksuite disks.

2006-08: Disk Mirroring

Mirror The Drives

Use the 256M slice 7 of the drive for the metadata partition. Naming convention

• d10: the metadisk slice name
• d11: the first copy of the d1 slice
• d12: the second copy of the d1 slice

Copy partition from one drive to another. The easiest way:

• run format, pick source disk.
• name the partition layout
• in format, pick dest. disk. partition, "select" and pick the partition name, run "label"
• we don't need to do "newfs"

Set up meta database

• metadb no args, "nothing defined
• metadb -f -a -c 3 c1t0d0s7 c1t1d0s7 (source and dest disks) three dbs per slice.
• metainit -f d11 1 1 c1t0d0s0 <-- one of the partitions you want to mirror
• 1 1 use one slice for it
• -f force if the disk is in use
• "d11" = slice 1, mirror 1
• metainit -f d12 1 1 c1t1d0s0

Repeat for each slice that we're going to use. Map the new drive to the metadrive name

• metainit d10 -m d11 <-- set up onesided mirror; repeat for each slice.
• metastat will show us current setup

Now, tell vfstab to boot off off the metadevice

• metaroot d10 - metaddrive name for / (it edits /etc/system and /etc/vfstab)
• edit /etc/vfstab manually, set /var to e.g. /dev/md/dsk/d30
• Reboot
• in /etc/vfstab, make swap the mirror, d20
• Now, sync up the mirrors; d10 was already attached to d11, now attach d12
  • metattach d10 d12
  • for a 70G drive, it'll take about 3 hours to complete the mirroring. This should be done during a quiet time.

Boot from either mirror

In the ROM monitor: ok>

• show-disks to get the logical names for the disks
• do nvalias to give the boot disks names, e.g. root-disk & root-mirror
• devalias will show the existing aliases
• now test that we can boot using the two aliases
• when Solaris is up, test it with metastat
• ok> setenv boot-device root-disk root-mirror
• on systems with a diag-device in ROM, must set that too
• do a reset-all to simulate power cycle
• set auto-boot true
• set local-mac-address to FALSE - all interfaces have the same MAC address

Replace A Drive

*Probably* all you need to do is

 metareplace -e d10 c0t0d0s0

... which will replace the device and enable it.

Here's the much longer way:

To replace a disk:

• metadetach d10 d11 # (remove d11 from the d10 mirror. Do this for all slices on the failed disk)
• metaclear d11 # (Do this for all slices on the failed disk)
• metadb -d /dev/dsk/c0t0d0s1 # (clear the meta databases off of the failed disk)
• replace physical disk.
• Do whatever you need to do to AddAndRemoveDisk
• prtvtoc /dev/rdsk/c0t1d0s2 | fmthard -s - /dev/rdsk/c0t0d0s2 # (copy the good disk's partition table to the new replacement disk)
• metadb -a -c 3 c0t0d0s2 # (Recreate databases)
• metainit d11 1 1 c0t0d0s0 # (Recreate submirrors. Do this for all slices on the disk)
• metattach d10 d11 # (Reattach the new drive sub mirror to the mirror -- rebuilding starts!)