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Sorry if this list is inappropriate. Pointers welcomed.
Using Solaris 10 Update 10, x86-64.
I have been a ZFS heavy user since available, and I love the system.
My servers are usually "small" (two disks) and usually hosted in a
datacenter, so I usually create a ZPOOL used both for system and data.
That is, the entire system contains an unique two-disk zpool.
This have worked nice so far.
But my new servers have SSD too. Using them for L2ARC is easy enough,
but I can not use them as ZIL because no separate ZIL device can be
used in root zpools. Ugh, that hurts!.
So I am thinking about splitting my full two-disk zpool in two zpools,
one for system and other for data. Both using both disks for
mirroring. So I would have two slices per disk.
I have the system in production in a datacenter I can not access, but
I have remote KVM access. Servers are in production, I can't reinstall
but I could be allowed to have small (minutes) downtimes for a while.
My plan is this:
1. Do a scrub to be sure the data is OK in both disks.
2. Break the mirror. The A disk will keep working, B disk is idle.
3. Partition B disk with two slices instead of current full disk slice.
4. Create a "system" zpool in B.
5. Snapshot "zpool/ROOT" in A and "zfs send it" to "system" in B.
Repeat several times until we have a recent enough copy. This stream
will contain the OS and the zones root datasets. I have zones.
6. Change GRUB to boot from "system" instead of "zpool". Cross fingers
and reboot. Do I have to touch the "bootfs" property?
Now ideally I would be able to have "system" as the zpool root. The
zones would be mounted from the old datasets.
7. If everything is OK, I would "zfs send" the data from the old zpool
to the new one. After doing a few times to get a recent copy, I would
stop the zones and do a final copy, to be sure I have all data, no
changes in progress.
8. I would change the zone manifest to mount the data in the new zpool.
9. I would restart the zones and be sure everything seems ok.
10. I would restart the computer to be sure everything works.
So fair, it this doesn't work, I could go back to the old situation
simply changing the GRUB boot to the old zpool.
11. If everything works, I would destroy the original "zpool" in A,
partition the disk and recreate the mirroring, with B as the source.
12. Reboot to be sure everything is OK.
So, my questions:
a) Is this workflow reasonable and would work?. Is the procedure
documented anywhere?. Suggestions?. Pitfalls?
b) *MUST* SWAP and DUMP ZVOLs reside in the root zpool or can they
live in a "nonsystem" zpool? (always plugged and available). I would
like to have a quite small(let say 30GB, I use Live Upgrade and quite
a fez zones) "system" zpool, but my swap is huge (32 GB and yes, I use
it) and I would rather prefer to have SWAP and DUMP in the data zpool,
if possible & supported.
c) Currently Solaris decides to activate write caching in the SATA
disks, nice. What would happen if I still use the complete disks BUT
with two slices instead of one?. Would it still have write cache
enabled?. And yes, I have checked that the cache flush works as
expected, because I can "only" do around one hundred "write+sync" per
Jesus Cea Avion _/_/ _/_/_/ _/_/_/
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jabber / xmpp:j...@jabber.org _/_/ _/_/ _/_/_/_/_/
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"Things are not so easy" _/_/ _/_/ _/_/ _/_/ _/_/ _/_/
"My name is Dump, Core Dump" _/_/_/ _/_/_/ _/_/ _/_/
"El amor es poner tu felicidad en la felicidad de otro" - Leibniz
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