Mike, yep, there are a lot of benchmarks proving it (plus it just makes sense)
http://stu.mp/2009/12/disk-io-and-throughput-benchmarks-on-amazons-ec2.html http://www.mysqlperformanceblog.com/2009/08/06/ec2ebs-single-and-raid-volumes-io-bencmark/ http://orion.heroku.com/past/2009/7/29/io_performance_on_ebs/ -Ben Standefer On Thu, Jun 3, 2010 at 4:41 PM, Mike Subelsky <m...@subelsky.com> wrote: > Ben, > > thanks for that, we may try that. I did find an AWS forum tidbit from > two years ago: > > "4 ephemeral stores striped together can give significantly higher > throughput for sequential writes than EBS." > > http://developer.amazonwebservices.com/connect/thread.jspa?messageID=125197𞤍 > > -Mike > > On Thu, Jun 3, 2010 at 5:57 PM, Ben Standefer <b...@simplegeo.com> wrote: >> The commit log and data directory are on the same mounted directory >> structure (the 2 RAID 0 striped ephemeral disks) rather than using 1 >> of the ephemeral disks for the data and 1 of the ephemeral disks for >> the data directory. While it's usually advised that for disk >> utilization reasons you keep the commit logs and data directory on >> separate disks, our RAID0 configuration gives us much more space for >> the data directory without having to mess with EBSes. We've found it >> to be fine for now. >> >> I see how my XFS snapshots reference was confusing. Our plan is to >> have a single AZ use EBSes for the data directory so that we can more >> easily snapshot our data (trusting that our AZ-aware EndPointSnitch), >> while other AZs will continue ephemeral drives. >> >> -Ben Standefer >> >> >> On Thu, Jun 3, 2010 at 1:26 PM, Mike Subelsky <m...@subelsky.com> wrote: >>> Ben, >>> >>> do you just keep the commit log on the ephemeral drive? Or data and >>> commit? (I was confused by your reference to XFS and snapshots -- I >>> assume you keep data on the XFS drive) >>> >>> -Mike >>> >>> On Thu, Jun 3, 2010 at 2:29 PM, Ben Standefer <b...@simplegeo.com> wrote: >>>> We're using Cassandra on AWS at SimpleGeo. We software RAID 0 stripe >>>> the ephemeral drives to achieve better I/O and have machines in >>>> multiple Availability Zones with a custom EndPointSnitch that >>>> replicates the data between AZs for high availability (to be >>>> open-sourced/contributed at some point). >>>> >>>> Using XFS as described here >>>> http://developer.amazonwebservices.com/connect/entry.jspa?externalID=1663 >>>> also makes it very easy to snapshot your cluster to S3. >>>> >>>> We've had no real problems with EC2 and Cassandra, it's been great. >>>> >>>> -Ben Standefer >>>> >>>> >>>> On Thu, Jun 3, 2010 at 11:51 AM, Eric Evans <eev...@rackspace.com> wrote: >>>>> On Thu, 2010-06-03 at 11:29 +0300, David Boxenhorn wrote: >>>>>> We want to try out Cassandra in the cloud. Any recommendations? >>>>>> Comments? >>>>>> >>>>>> Should we use Amazon? Rackspace? Something else? >>>>> >>>>> I personally haven't used Cassandra on EC2, but others have reported >>>>> significantly better disk IO, (and hence, better performance), with >>>>> Rackspace's Cloud Servers. >>>>> >>>>> Full disclosure though, I work for Rackspace. :) >>>>> >>>>> -- >>>>> Eric Evans >>>>> eev...@rackspace.com >>>>> >>>>> >>>> >>> >>> >>> >>> -- >>> Mike Subelsky >>> oib.com // ignitebaltimore.com // subelsky.com >>> @subelsky // (410) 929-4022 >>> >> > > > > -- > Mike Subelsky > oib.com // ignitebaltimore.com // subelsky.com > @subelsky >
