Re: md on shared storage

[Michael Clark <michael@metaparadigm.com>]

On 11/13/02 08:25, Brian Jackson wrote:
> Here's a question for all those out there that are smarter than me(so I 
> guess that's most of you then :) I looked around (google, kernel source, 
> etc.) trying to find the answer, but came up with nothing.
> Does the MD driver work with shared storage? I would also be interested 
> to know if the new DM driver works with shared storage(though I must 
> admit I didn't really try to answer this one myself, just hoping 
> somebody will know).

They should work, obviously with some caveats. Having 2 hosts both
trying to reconstruct the same md RAID1 may cause some troubles.

> I ask because I seem to be having some strange problems with an md 
> device on shared storage(Qlogic FC controllers). The qlogic drivers spit 
> out messages for about 20-60 lines then the machines lock up. So the 
> drivers were my first suspicion, but they were working okay before. So I 
> went back and got rid of the md device and now everything is working 
> again. Anybody got any ideas?

Could be a stack related problem with the qlogic driver. The additional
stack pressure of the md layer perhaps ?? The 20-60 lines of logs in
would probably give some ideas.

I have a couple of shared storage clusters that were using qla2300
driver, ext3 and LVM1 and they would periodically ooops. Removed LVM
and the systems are now rock solid.

~mc