Probably

I came across an intriguing problem today whilst trying to rebuild a server. The server was physically located somewhere I couldn’t utilise a boot server, so I decided to quickly throw together a WAN Boot server (which I won’t go into here, but see ref [1] below).

Having already taken a flash archive (flar) of a Solaris 10 update 6 system the intention was to install this using WAN Boot onto a fresh system, with ZFS root. The first time I ran the install, it failed with a core dump in pfinstall. A bit of digging around [2] showed that the cause of my problem was the lack of support for flash installs and ZFS root. The only option with WAN Boot though is flash.

Hmm. So, I wondered if it would be possible to do the flash install over WAN boot to a standard UFS filesystem, then migrate it to ZFS. The answer is yes! [3]

With the target system having two disks, I did a flar install to one of the disks, then created a zpool with the other disk in when the system had booted (first of all I made sure the disk had a VTOC label rather than an EFI label, using ‘format -e’).

Once I had my zpool, I then did a LiveUpgrade of the system to the ZFS root as per the documentation in reference [3] below.

When the machine had booted from the new ZFS rooted boot environment (BE) I removed the previous BE with ludelete, formatted the first drive again to ensure it contained a VTOC label, then added it to the zpool with ‘zpool attach rpool c1t0d0s0 c1t1d0s0′. Oh, I had a weird problem here with adding the disk to the pool. ZFS kept complaining “cannot attach c1t1d0s0 to c1t0d0s0: device is too small”, which I knew was impossible as they were the same type of disk. A quick “prtvtoc /dev/rdsk/c1t0d0s0 | fmthard -s – /dev/rdsk/c1t1d0s0″ fixed this and the zpool attach worked just fine.

Sorted. System installed over WAN Boot and converted to ZFS root.

References

[1] Guide to WAN Boot

[2] ZFS root doesn’t support Flash install

[3] Migrating a UFS root to a ZFS root