Robert Milkowski wrote:
JB> So, normally, when the script runs, all snapshots finish in maybe a minute
JB> total. However, on Sundays, it continues to take longer and longer. On
JB> 2/25 it took 30 minutes, and this last Sunday, it took 2:11. The only
JB> thing special thing about Sunday's snapshots is that they are the first
JB> ones created since the full backup (using NetBackup) on Saturday. All
JB> other backups are incrementals.
hmmmmm do you have atime property set to off?
Maybe you spend most of the time in destroying snapshots due to much
larger delta coused by atime updates? You can possibly also gain some
performance by setting atime to off.
Yep, atime is set to off for all pools and filesystems. I looked through
the other possible properties, and nothing really looked like it would
really affect things.
One additional weird thing. My script hits each filesystem
(email-pool/A..Z) individually, so I can run zfs list -t snapshot and find
out how long each snapshot actually takes. Everything runs fine until I
get to around V or (normally) W. Then it can take a couple of hours on the
one FS. After that, the rest go quickly.
JB> I've looked a bit, and can't find anything that tells me if there will be
JB> any sort of a hit on my performance if I upgrade the pools. I'm especially
JB> cautious as this is our production email server. Will an upgrade cause
JB> load/performance problems? Will I need to take down the IMAP server while
JB> I do this? Also, the whole 'older software versions' mentioned above: what
JB> is the older software I'd have to worry about? Just the ZFS tools? If the
JB> array is staying on this server, do I even have to worry about this? I'm
JB> running a patched 2006/06 OS.
It's about zfs on-disk format.
By doing upgrade it won't issue any significant number of IOs (should
complete in a second or so). It won't hit performance but it will add
new features like hot spare support (in version 3) or proper disk
space accounting for raid-z* file systems (but they have to be
re-created).
There's nothing to worry about upgrade and of course you can do it
online without stopping applications. However once you upgrade you
won't be able to import version 3 pool on older systems with version 2
only support (so basically you won't be able to import on S10U2).
So once you're sure that system is working correctly for some time after
applying
last patches you can safely upgrade.
OK. Good to know. I figured it was something along those lines, but
wasn't sure. I'm not overly concerned about the import part, so, nothing
to worry about there, then.
Thanks for your help on this!
--
Joe Barbey IT Services/Network Services
office: (715) 425-4357 Davee Library room 166C
cell: (715) 821-0008 UW - River Falls
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