Cluster attached storage to linux .... anyone? HP MSA 1000 for example.

[Fraser Campbell]

On Sunday 01 April 2007 17:07, tleslie wrote:

> i read one article way back about some firewire cluster setup
> and it did talk about the drivers making it as easy as a  /dev ref. to
> get at the storage, and in that case it was easy because it was a single
> drive system so i'd imagine it was just /dev/xxa1  /dev/xxa2  for the
> different partitions on the drive array setup.
> But for the MSA1000 (MSA 500 or 1500 for that matter),
> you can have a shit load of defined drives sets and partitions.
>
> anyone got any insight?

You haven't given a clear idea of why you're considering fibrechannel ...

One question would be do you expect to share the storage with multiple 
servers?  If so you will need FC switches.

If sharing the storage then are you sharing LUNs, or will each server mount 
unique LUNs?

If you're sharing LUNs then you'll want a reasonably robust means of ensuring 
that your volumes don't get simultaneously mounted (LVM tagging works ok for 
this).

If on the other hand you do want to simultaneously mount the common LUNs then 
you need a cluster aware filesystem - OCFS2, GFS, veritas, polyserve, ???

If you want redundancy then you'll want to have dual FC HBAs per server, dual 
FC switches and dual controllers on the MSA1500 ... then some multipathing 
layer on top of that.  device mapper multipath can work well on a real SAN, 
not certain on the MSAs right now.  md multipath never used it, might work.  
qlogic drivers have built in multipath support and in some cases it is the 
best solution (I believe it is in the case of MSA devices).


> I'd hope i could just see the partitions over the arrays as  /dev/xxxYn
> format, but why am i thinking it might not be that easy.
> And then what about if you are addressing multiple MSA devices ?

I'm not a FC expert but I'd guess if you throw multiple MSAs on the same 
fabric then your servers will be able to see them all.  You would definitely 
want persistent naming setup in this case (udev rules are good enough) as 
there's no guarantee that the devices will be found in the same order.

-- 
Fraser Campbell <fraser-Txk5XLRqZ6CsTnJN9+BGXg at public.gmane.org>                 http://www.wehave.net/
Georgetown, Ontario, Canada                               Debian GNU/Linux
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