I'm running a 27 node cassandra cluster on SAN without issue. I will be perfectly clear though, the hosts are multi-homed to different switches/fabrics in the SAN, we have an _expensive_ EMC array, and other than a datacenter-wide power outage, there's no SPOF for the SAN. We use it because it's there, and it's already a sunk cost.
I certainly would not go out of my way to purchase SAN infrastructure for a C* cluster, it just doesn't make sense (for all the reasons others have mentioned). Any more, you can load up a single 2U server with multi-TB worth of disk, so the aggregate storage capacity of your C* cluster could potentially be as much as a SAN you would purchase (and a lot less hassle too). As a counter argument though, anyone running a C* cluster on the Amazon cloud is going to be using SAN storage (or some kind of proprietary storage array) at the lowest layers...Amazon isn't going to have a bunch of JBOD running their cloud infrastructure. However, they've invested in the infrastructure to do it right. - Mike On Thu, Feb 21, 2013 at 6:08 PM, P. Taylor Goetz <ptgo...@gmail.com> wrote: > I shouldn't have used the word "spinning"... SSDs are a great option as > well. > > I also agree with all the "expensive SPOF" points others have made. > > Sent from my iPhone > > On Feb 21, 2013, at 6:56 PM, "P. Taylor Goetz" <ptgo...@gmail.com> wrote: > > Cassandra is designed to write and read data in a way that is optimized > for physical spinning disks. > > Running C* on a SAN introduces a layer of abstraction that, at best > negates those optimizations, and at worst introduces additional overhead. > > Sent from my iPhone > > On Feb 21, 2013, at 6:42 PM, Kanwar Sangha <kan...@mavenir.com> wrote: > > Ok. What would be the drawbacks J**** > > ** ** > > *From:* Michael Kjellman > [mailto:mkjell...@barracuda.com<mkjell...@barracuda.com>] > > *Sent:* 21 February 2013 17:12 > *To:* user@cassandra.apache.org > *Subject:* Re: Cassandra with SAN**** > > ** ** > > No, this is a really really bad idea and C* was not designed for this, in > fact, it was designed so you don't need to have a large expensive SAN.**** > > ** ** > > Don't be tempted by the shiny expensive SAN. :)**** > > ** ** > > If money is no object instead throw SSD's in your nodes and run 10G > between racks**** > > ** ** > > *From: *Kanwar Sangha <kan...@mavenir.com> > *Reply-To: *"user@cassandra.apache.org" <user@cassandra.apache.org> > *Date: *Thursday, February 21, 2013 2:56 PM > *To: *"user@cassandra.apache.org" <user@cassandra.apache.org> > *Subject: *Cassandra with SAN**** > > ** ** > > Hi – Is it a good idea to use Cassandra with SAN ? Say a SAN which > provides me 8 Petabytes of storage. Would I not be I/O bound irrespective > of the no of Cassandra machines and scaling by adding **** > > machines won’t help ?**** > > **** > > Thanks**** > > Kanwar**** > > ** ** > > ---------------------------------- > Copy, by Barracuda, helps you store, protect, and share all your amazing > things. Start today: www.copy.com <http://www.copy.com?a=em_footer>. **** > > **** > >
