Re: Can the Red Hat Cluster Manager be used with a cheap NAS for shared storage?

Tim Burke wrote:
> 
> Red Hat Cluster Manager requires shared disk storage among cluster 
> members.  This requirement precludes you from being able to configure 
> Cluster Manager using IDE.
> 
> Nick Urbanik wrote:
> 
> >Dear folks,
> >
> >I want to build a NAS (network attached storage) box using software RAID on
> >cheap IDE disks and gigabit Ethernet cards.  Could such a beast be made to work
> >with the Red Hat Cluster Manager?  We can't afford a SAN, or a special purpose
> >RAID system.
> >
> >If this is the wrong list, please point me to the right one.

The problem is, you need to make your NAS redundant, and have redundant
network (multiple NICs on multiple switches) for NAS to be suitably
HA.  If you needs are less than 120-240 GB, my advice is to get a
couple of four disk SCSI enclosures and a pair of SCSI controllers for
each system, and then use software RAID.  Set up either a pair of
mirrored RAID5, or a pair of mirrored RAID0 (stripes), preferably with
hot spares.  Don't use RAID5 if you do a lot of writing.  I do admit
this can be expensive, probably about $4,000 retail (but if you are
a scrounger like me, it can be had cheaper - refurbs and so forth can
easily save $1000).  You will have to change the SCSI initiator IDs of
the SCSI controllers on one of the nodes; you can usually do this in
the firmware setup of the SCSI card.  Use LVD SCSI to avoid cable
length issues.  This is probably going to be your cheapest HA setup
that can be attached to two nodes.

More than two nodes gets tricky; one option is to use the above setup
as the basis of an HA NAS setup (along with redundant networking) and
then roll your own LVS since Redhat Piranha doesn't support this.  I
suggest heading over to the [email protected] for some
expert help if you choose to go this route.

Frankly, I would do RAID before clustering in most cases, as in most
cases the data is the most important part of the the whole setup.

-- 
John Cronin
mailto: `echo [email protected] | sed 's/[NOSPAM]//g'`