[OmniOS-discuss] Pliant/Sandisk SSD ZIL

[Derek Yarnell]

On 2/18/14, 9:41 PM, Marion Hakanson wrote:
> No better than with the ZIL running on the pool's HDD's?  Really?

Yes it would seem I was getting just as bad svc_t from these Pliant SSDs
then from the pools spinners.

> Out of curiosity, what HBA is being used for these drives (and slog)
> in this R720xd, H710 or H310?  Something else?

This is a R720xd shipped with a pristine LSI card (mine even came with
IT firmware).  You will need to talk to your rep but they can do it.  My
hope here was to get a fully supported OmniOS box from Dell which the
biggest problem was before making me take a H710/H800 card.  While we
have been successful running ZFS with a R510 w/ H700s drives all in R0
and setting zfs_nocacheflush it just isn't right.  We have also never
gone more than 9 data drives with the R0 configuration (also this has
been mostly on Nexenta not Omni).

> 
> I'm also looking at the R720xd here, though I was thinking of using the
> Intel DC S3700 SSD for a log device (in one of the internal flex-bay's),
> with the pool drives being of the 2.5" form-factor.

The R720xd flex bays are no longer internal but in the back of the
machine[1].  I actually will test some spare DC S3700 drives as the slog
devices that we have for a Ceph cluster in this in the next few days and
will report back on this thread.

One also thing to note is that Dell "Enterprise" drives have this
problem of not spinning up[2] which made for a very fun to get
installed.  I had to install on a non-dell disk that was equal or
smaller than my OS disks then modify the /kernel/drv/sd.conf file, then
mirror the rpool reboot and then detach the non-dell drive and add the
other drive back to the mirror.

[1] - http://www.anchor.com.au/blog/2012/10/shiny-new-hardware-dell-r720xd/
[2] - https://www.illumos.org/issues/2091

Thanks,
derek

-- 
Derek T. Yarnell
University of Maryland
Institute for Advanced Computer Studies