choosing a file system

[Bron Gondwana]

On Thu, Jan 08, 2009 at 08:01:04AM -0800, Vincent Fox wrote:
> (Summary of filesystem discussion)
> 
> You left out ZFS.
> 
> Sometimes Linux admins remind me of Windows admins.
> 
> I have adminned a half-dozen UNIX variants professionally but
> keep running into admins who only do ONE and for whom every
> problem is solved with "how can I do this with one OS only?"

We run one zfs machine.  I've seen it report issues on a scrub
only to not have them on the second scrub.  While it looks shiny
and great, it's also relatively new.

Besides, we had a disk _fail_ early on in our x4500 - Sun shipped
a replacement drive, but the kernel was unable to recognise it:

---

"Nothing odd about how it snaps in. We can see the connectors in the
slot - they seem fine as far as we can tell. The drive's 'ok' light is
on and the blue led lit."

Which suggests the server thinks the drive is fine, but the dmesg data
definitely suggests it isn't.

I've also included the output of hdadm display below as well, which
shows that currently it thinks the drive is not present, even though the
last thing reported in the dmesg log is that the device was connected.

Aug 14 21:59:13 backup1  SATA device attached at port 0
Aug 14 21:59:13 backup1 sata: [ID 663010 kern.info]
+/pci at 2,0/pci1022,7458 at 8/pci11ab,11ab at 1 :

The output of hdadm display shows that the machine definitely thinks the
drive is NOT connected.

---

Sun's response was to wait for the next kernel upgrade - there was a bug
that made that channel unusable even after a reboot.

> So far ZFS ticking along with no problems and low iostat numbers
> with everything in one big pool.  I have separate fs for data, imap, mail
> but haven't seen any need to carve mail spool into chunks at all.
> There were initial problems noted here in the mailing lists way back
> in Solaris 10u3 but that was solved with the fsync patch and since then
> it's been like butter.  Mail-store systems nobody ever needs to look
> at them because it "just works".

I'd sure hate to lose the entire basket, say due to an unknown bug in
zfs.

Besides, I _know_ Debian quite well.  We don't have any Solaris
experience in our team.  The documentation looks quite good, but it's
still a lot of things that work differently.  I tell you what,
maintaining Solaris and using the Solaris userland feels like going
back 20 years - and the whole "need a sunsolve password and only get
some patches - permission denied on others" crap.  I don't need that.

So while I apprciate that ZFS has some advantages, I'd have to say
that they need to be weighed up against the rest of the system, and
the "all the eggs in a relatively new basket" argument.  Also, the
response we've had from Linus when we find kernel issues has been
absolutely fantastic.

Bron ( Debian on the Solaris kernel would be interesting... )