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



We use iSCSI in our development labs for GFS clustering.  Basically, GFS requires that the underlying storage be concurrently accessible from all nodes in the cluster.  This rules out a shared scsi bus between nodes, but fibre channel, iSCSI and gndb all provide the ability to access the underlying storage concurrently.   From the basic descriptions of the DS300, I don't see any reason it wouldn't work very well with GFS.  It provides either fibre channel or iSCSI support.

Kevin

On Tue, 2006-11-07 at 18:33 -0500, David Brieck Jr. wrote:
On 11/7/06, Riaan van Niekerk <riaan obsidian co za> wrote:
> > 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?
> >
>
> hi David
>
> do you have a link to the page with that statement? "linux clustering"
> is somewhat of an ambiguous term. Within the context of Red Hat software
> (excluding Linux Virtual Server and high-performance computing
> clusters), it can mean either:
>
> a) Cluster Suite (without GFS) - only one node in a cluster accesses the
> storage at a time. if you fail/switch over, one node unmounts an FS,
> another one mounts it.
>
> b) GFS (which implies/includes Cluster Suite) - multiple nodes accessing
>    the same LUN with a (G)FS on top of it
>
> I am not familiar with entry-level iSCSI initiators. I always thought
> iSCSI is logically like fibre, e.g. multiple hosts in the same raidgroup
> can concurrently access the same LUN/FS. Perhaps these entry-level iSCSI
> arrays are more like regular SCSI meaning that they do not support
> multiple initiators accessing the same LUN behind a target (storage
> processor).
>
> I had a look at EMC cert matrix for the AX100/150 series arrays
> http://www.emc.com/interoperability/matrices/AX_Series_SupportMatrix.pdf
> thes entry-level EMC iSCSI arrays also only supports non-clustered Linux.
>
> iSCSI will allow you to "do the same thing" as GNDB:
> GNDB client and server are replaced iSCSI initiator (Linux host) and
> target (dedicated hardware, e.g. EMC array, or software target - not yet
> considered production-ready nor included with RHEL). However, if the
> hardware has an explicit exclusion of Linux clustering, you are stuck,
> not being able to have two nodes aaccess the storage at the same time..
>
> HTH
> Riaan
>
> > 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.
> >
> > --
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> > Linux-cluster redhat com
> > https://www.redhat.com/mailman/listinfo/linux-cluster
>
>
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>
>

Here the PDF I was looking at:
http://www-03.ibm.com/servers/storage/disk/ds/pdf/ds300400_interop.pdf

It says it supports Microsoft Clusters so I don't know why it wouldn't
support linux. I also found somewhere else that said more specifically
that it doesn't support RedHat Cluster Manager, but as far as I'm
concerned it has nothing to do with that unless you're talking about
fencing, in which case it would work for me since I'm using power
fencing.

Anyone from RedHat mind chiming in? It's not on the hardware
compatibility list, but there are many things that work that aren't on
that list.

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