[Gllug] Hardware recommendation, esp. SANs and shared storage

[Simon Trimmer]

On 8 Aug 2002, Chris Ball wrote:
> >>> On Thu, 8 Aug 2002 18:42:32 +0100 (BST), Simon Trimmer <simon at urbanmyth.org> said:
> 
>    ST> Applying raid at the array level is pricey, so I havn't looked in
>    ST> that direction, but you certainly want raid somewhere as disks
>    ST> fail scarily often. 
> 
> I'm working with a fibrechannel SAN running VeritasFS with SCSI RAID.  

Hehehe, not quite snap

(I've spent the last two years writing a Linux based fibrechannel appliance
for Veritas)


>    ST> Fibre channel cards.  Overall, the best cards I've used are the
>    ST> QLogic 22xx and 23xx series. There are plenty of fully open
>    ST> source drivers (including their own) and the performance is
>    ST> extremely good. Don't be fooled by the source emulex driver, it
>    ST> builds wrappers and links against a binary core.
> 
> We've had problems with the Emulex drivers.  The latest revision doesn't
> work with our firmware, downgrading to an older revision broke things
> even more, and the version we're currently running very occasionally
> exhibits SCSI errors and then panics the RAID array. 

Interesting, on what type of array and is this using a Linux initiator?

As you can tell, I'm not a fan of Emulex...their latest Linux driver causes
fabric disruption on my main brocade based test rig.


> You'd be surprised how hard it is to try and perform sensible debugging
> on raw SCSI errors over fibrechannel..

Oh I agree. If you control the OS and the hba driver there are things you can
try to narrow down scsi problems, firmware specs help when you're working
with drivers but when things really go bad only a FC analyser will do. The
few we have usually float around cupboards in California.


>    ST> We had a couple of compaq boxes, they can have some wierd array
>    ST> hardware but I think we got them working well enough. They aren't
>    ST> here anymore.
> 
> I like Compaq a lot.  They have things like PXE and virtual floppy on
> their workstations, so the machines are nice and easy to maintain.
> Haven't any experience of their large x86 servers, though.

That's pretty cool -

One of my great searches is x86 servers that have supervisor modules like
Real Computers, so when you kill a machine you can perform remote analysis
even though the internals are way off in hyperspace. The DRAC boards in Dells
require a windows client (I have a serial cable I've been meaning to try) and
the PCWeasel cards just don't work well enough to be practical.  Any idea
what support compaq have?

-Simon

Simon Trimmer <simon at urbanmyth.org>


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