Re:Google: 'At scale, everything breaks'
by herf on Thursday June 23, 2011 @11:37AM
(#2688232)
Am a little bit surprised Google hasn't incorporated SSD more.
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For lots of applications, the workloads are either memory only or large sequential IOs. SSDs matter less in both situations.
Too expensive, too prone to failure http://www.codinghorror.com/blog/2011/05/the-hot-crazy-solid...
Having installed almost 200 Intel SSDs into servers with 0 failures, I doubt his anecdotal evidence.
Also compare with Intel's reported annual failure rates: http://www.anandtech.com/show/4244/intel-ssd-320-review and a french retailer: http://www.anandtech.com/show/4202/the-intel-ssd-510-review/...
SSDs are actually cheaper per IOPS.
Considering that everything we knew about hard disk reliability was shown to be wrong (by Google), I wouldn't be surprised if the same holds for SSDs.
Re:Google: 'At scale, everything breaks'
by sliverstorm on Thursday June 23, 2011 @02:59PM
(#2689325)
It's hard to see SSD's being a clear win on the surface. It would be very interesting though to see if the cost begins to change when you consider power savings (much smaller than hoped, but they do exist), figure out how much they'd save on HVAC in the datacenters, etc.
Having worked on power-aware hybrid storage for the last two years, the power savings per GB is pretty much zero; there is significant W/IOPS savings but that still doesn't pay for the capital cost. Performance is really the reason to use SSDs.
Re:Google: 'At scale, everything breaks'
by sliverstorm on Thursday June 23, 2011 @03:26PM
(#2689440)
per GB is an excellent point, I had not considered that.
think commodity... have ssd's reached the commodity level yet? from a commodity stand point, i think it would be far more likely that google would use an array of SD cards per node. SSDs are really just an array of SD cards anyway, with a pile of hype and marketing piled on. you would still get most benefits of an SSD. power usage (esp at idle) might even be less than an ssd. google could develop their own wear leveling algorithms, and the rest of the stuff that an SSD controller provides for the internal flash. replacement costs could be less as well over time.
I was at a linux user group meeting recently where a talk was given by a Google sysadmin where he talked about hard drive reliability. Someone asked him about SSDs to which he replied that he couldn't talk about it. My take is that they are definitely trying out SSDs, but either 1) found SSDs provide a huge competitive benefit and don't want to publicly share that knowledge or 2) they simply don't have enough data yet. I'm leaning towards #1.