[Linux-cluster] Re: Storage Problems, need some advice

[David Brieck Jr.]

On 11/6/06, David Brieck Jr. <dbrieck at gmail.com> wrote:
> Some of you may have noticed the problems I've been posting to the
> mailing with my storage. For those who haven't here a quick rundown of
> my setup:
>
> GNBD Servers w/ clustered SCSI enclosure
> GNBD Clients w/ multipath
> CLVM
> GFS and DLM
>
> I've been having crashes, lockups and poor performance with my setup
> almost since it was first setup. I've tried getting rid of multipath
> and went down to only one GNBD server but I'm still suffering from
> random crashes under moderate to high I/O. I'm not getting any errors
> in the logs at all that can help, not even kernel errors any more.
>
> So I've simpled to GNBD Server -> GNBD Clients -> CLVM -> GFS which is
> exactly what is specified in the manual:
> http://www.redhat.com/docs/manuals/csgfs/browse/rh-gfs-en/ch-gnbd.html
> and it still seems to act very flaky. My GNBD Server(s) don't crash,
> it's always the client nodes that end up crashing. The only connecting
> factor seems to be I/O on the GNBD.
>
> So I have to find a solution that's going to work and I don't think
> anything with GNBD is going to work regardless of hardware. So that
> pretty much only leaves FC or iSCSI. I don't want to go with FC due to
> cost considerations and I already have a GB network setup just for
> storage (GNBD) and cluster functions and another for regular LAN
> traffic.
>
> So if I go with iSCSI then I can completely get rid of the GNBD aspect
> and possibly CLVM as well. However, I am concerned about performance,
> especially since I'd want to put MySQL data on it.
>
> The Promise 500i
> (http://www.promise.com/product/product_detail_eng.asp?segment=VTrak&product_id=149)
> seems like it nice solution (much cheaper than the Dell CX300 I would
> also consider) but will it deliver performance wise?
>
> Would you want an enclosure with SCSI drives or SATA drives? And if
> you went with SATA drives, would you go with the 10k 1.5Gb drives or
> the 7200 3Gb drives for maximum performance?
>
> If you wanted SATA drives is the Promise the best solution? If you
> wanted iSCSI with SCSI drives what would you go with?
>
> Thanks for the help, I really need to get this storage situation under control.
>

After doing much more research I came across the DS300 by IBM. It uses
SCSI drives, is fully redundant, does iSCSI and doesn't cost an arm
and a leg (just an arm). My question is, their site says linux
clustering isn't supported, but does it have to be? Doesn't iSCSI let
you do the same thing GNBD does?

Also, I talked to someone on their chat who said I could use any U320
drive with it, basically I could reuse the drives I already have and
just not use my old enclosure. Does that sound right? Any reason I
couldn't do that other than loosing all my data?

Anyone using a DS300? Seems like with 15k drives it would be pretty darn fast.