jel+...@cs.uni-magdeburg.de said:
> 2nd) Never had a Sun STK RAID INT before. Actually my intention was to create
> a zpool mirror of sd0 and sd1 for boot and logs, and a 2x2-way zpool mirror
> with the 4 remaining disks. However, the controller seems not to support
> JBODs :( - which is also bad, since we can't simply put those disks into
> another machine with a different controller without data loss, because the
> controller seems to use its own format under the hood.
Yes, those Adaptec/STK internal RAID cards are annoying for use with ZFS.
You also cannot replace a failed disk without using the STK RAID software
to configure the new disk as a standalone volume (before "zpool replace").
Fortunately you probably don't need to boot into the BIOS-level utility,
I think you can use the Adaptec StorMan utilities from within the OS, if
you remembered to install them.
> Also the 256MB
> BBCache seems to be a little bit small for ZIL even if one would know, how to
> configure it ...
Unless you have an external (non-NV cached) pool on the same server, you
wouldn't gain anything from setting up a separate ZIL in this case. All
your internal drives have NV cache without doing anything special.
> So what would you recommend? Creating 2 appropriate STK INT arrays and using
> both as a single zpool device, i.e. without ZFS mirror devs and 2nd copies?
Here's what we did: Configure all internal disks as standalone volumes on
the RAID card. All those volumes have the battery-backed cache enabled.
The first two 146GB drives got sliced in two: the first half of each disk
became the boot/root mirror pool. The 2nd half was used for a separate-ZIL
mirror, applied to an external SATA pool.
Our remaining internal drives were configured into a mirrored ZFS pool
for database transaction logs. No need for a separate ZIL there, since
the internal drives effectively have NV cache as far as ZFS is concerned.
Yes, the 256MB cache is small, but if it fills up, it is backed by the
10kRPM internal SAS drives, which should have decent latency when compared
to external SATA JBOD drives. And even this tiny NV cache makes a huge
difference when used on an NFS server:
http://acc.ohsu.edu/~hakansom/j4400_bench.html
Regards,
Marion
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