[Linux-cluster] wishing to run GFS on iSCSI with redundancy

[Lon Hohberger]

On Wed, Jun 27, 2007 at 03:54:07PM +1200, Rohit Grover wrote:
> Hello,
> 
> We'd like to run GFS in a cluster serviced by a pool of iSCSI disks.  
> We would like to use RAID to add redundancy to the storage, but  
> there's literature on the net saying that linux's MD driver is not  
> cluster safe. Since CLVM doesn't support RAID, what options do we  
> have other than pairing the iSCSI disks with DRBD?

Ok, couple of notes:

* MD is only unsafe in a cluster if it's used on multiple cluster nodes.
That is, it should be fairly easy to implement a resource agent which
assembles MD devices from network block devices - on one node at a time.

* DRBD only will work with two writers (if 0.8.x+).  I'm not sure how many
mirror targets you can maintain.

* Aren't most iSCSI targets RAID arrays already (?)

-- 
Lon Hohberger - Software Engineer - Red Hat, Inc.