You're pricing it out at $ per GB… that's not the way to look at it. Price it out at $ per IO… Once you price it that way, SSD makes a LOT more sense.
Of course, it depends on your workload. If you're just doing writes, and they're all sequential, then cost per IO might not make a lot of sense. We're VERY IO bound… so for us SSD is a no brainer. We were actually all memory before because of this and just finished a big SSD migration … (though on MySQL)… But our Cassandra deploy will be on SSD on Softlayer. It's a no brainer really.. Kevin On Tue, Aug 19, 2014 at 8:56 AM, Jeremy Jongsma <jer...@barchart.com> wrote: > The latest consensus around the web for running Cassandra on EC2 seems to > be "use new SSD instances." I've not seen any mention of the elephant in > the room - using the new SSD instances significantly raises the cluster > cost per TB. With Cassandra's strength being linear scalability to many > terabytes of data, it strikes me as odd that everyone is recommending such > a large storage cost hike almost without reservation. > > Monthly cost comparison for a 100TB cluster (non-reserved instances): > > m1.xlarge (2x420 non-SSD): $30,000 (120 nodes) > m3.xlarge (2x40 SSD): $250,000 (1250 nodes! Clearly not an option) > i2.xlarge (1x800 SSD): $76,000 (125 nodes) > > Best case, the cost goes up 150%. How are others approaching these new > instances? Have you migrated and eaten the costs, or are you staying on > previous generation until prices come down? > -- Founder/CEO Spinn3r.com Location: *San Francisco, CA* blog: http://burtonator.wordpress.com … or check out my Google+ profile <https://plus.google.com/102718274791889610666/posts> <http://spinn3r.com>
