Posted by: Denny Cherry
So I recently got an email from my NetApp sales rep telling me how awesome the Flash Cache is on the NetApp arrays. The email was really short and to the point.
Not sure if you’ve heard about how we’re leveraging cache to augment storage performance.
Here’s a recent article…
NetApp Customers Purchase More Than a PetaByte of Flash Cache for Greater Performance and Storage Efficiency.
Then there was a link to a press release telling about how NetApp customers have purchased a PetaByte of Flash Cache for their systems.
If you don’t know what the NetApp flash cache is, its a flash based IO card (kind of like a Fusion IO card) that the NetApp array uses as cache for reads. Each flash cache card gives you either 256 or 512 Gigs of cache that is used to speed up reads. You can put up to 4 TB of flash cache per NetApp array.
There’s two ways that you can take the statement that NetApp Customers have purchased more than a PetaByte of Flash Cache (which is VERY expensive to purchase). The first is that NetApp customers have such high IO loads that they need this cache layer to get the performance level. The second is that because NetApp arrays are all RAID 6 (yes I know that NetApp calls it RAID DP but the DP just stands for dual parity, which is RAID 6) that to get the write performance that others can get with RAID 10.
Given that so many NetApp customers are purchasing the Flash Cache, 5000 units have been sold since September 2009 and it’s shipping in 20% of the units that you can cram it into (according to the NetApp press release) this leads me to believe that its more about the later than the former. If that many customers needed this level of performance this soon after the option became available this leads me to believe that the NetApp arrays just weren’t able to give the level of performance that people needed until this Flash Cache can deliver.
But that’s just my take on the marketing spin.
UPDATE 7/12/2010: Corrected the post to show that NetApp’s flash cache only speeds up reads. Thanks to TechMute for pointing out the error in the post.