[CentOS] xServes are dead ;-( / SAN Question

James A. Peltier jpeltier at sfu.ca
Mon Nov 8 19:29:39 EST 2010

----- Original Message -----
| On 11/09/2010 12:58 AM, Tim Dunphy wrote:
| > Perhaps FreeNAS would fit the bill?
| >
| > http://freenas.org/features
| >
| >
| > Sent from my iPhone
| >
| > On Nov 8, 2010, at 6:52 PM, Gordon Messmer<yinyang at eburg.com> wrote:
| >
| >> On 11/07/2010 03:33 AM, Nicolas Ross wrote:
| >>>
| >>> Is there any other solution for building a SAN under linux ?
| How about openfiler: http://www.openfiler.com/
| Regards,
| Patrick
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All the tools to build a SAN are available out there, but it is a more complicated problem then you might expect to develop one.  For example, you could have GNU/Linux or Solaris 10 hosts that act as dumb iSCSI target enclosures with a bunch of disks in them.  This device could have FC, 1 or 10 GbE, Infiniband or some other adapter and attach to your existing storage fabric.  That's the easy part!

You then need a method for dealing with the high availability aspect.  You need to be able to fence the storage while a fail-over is taking place.  You need to (maybe) move MAC addresses and other storage IP bits.  This is the hard part!  Getting this right is not necessarily a trivial task.

Products like FreeNAS and OpenFiler only target the easy stuff.

Now, you could virtualize the head node using something like Xen, KVM or VMWare, then in case of failure or administrative necessity, fail over to the other physical hardware, which *may* negate some of the hard bits, but you would need to *really* test it in the most common scenarios to see if it fits your bill.

I have a solution that is currently centered around commodity storage bricks (Dell R510), flash PCI-E controllers, 1 or 10GbE (on separate Jumbo Frame Data Tier) and Solaris + ZFS.

So far it has worked out really well.  Each R510 is a box with a fair bit of memory, running OpenIndiana for ZFS/RAIDZ3/Disk Dedup/iSCSI.  Each brick is fully populated and in a RAIDZ2 configuration with 1 hot spare.  Some have SSDs most have SAS or SATA. I export this storage pool as a single iSCSI target and I attach each of these targets to the SAN pool and provision from there.

I have two VMWare physical machines which are identically configured.  If I need to perform administrative maintenance on the boxes I can migrate the host over to the other machine.  This works for me, but it took a really long time to develop the solution and for the cost of my time it *might* have been cheaper to just buy some package deal.

It was a hell of a lot of fun learning though. ;)

James A. Peltier
Systems Analyst (FASNet), VIVARIUM Technical Director
Simon Fraser University - Burnaby Campus
Phone   : 778-782-6573
Fax     : 778-782-3045
E-Mail  : jpeltier at sfu.ca
Website : http://www.fas.sfu.ca | http://vivarium.cs.sfu.ca
MSN     : subatomic_spam at hotmail.com

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