Dell’s announcement last week that their rebranded LSI RAID controllers, the H700 & H800, now have the ability to use certain local SSD disks as a read cache tier. This is the “CacheCade” technology LSI has offered since September 2010, and looks functionally similar to technologies like NetApp’s FlashCache, where SSD maintains a copy of “hot” blocks on the fast storage.
There are some limitations to it, namely that it will require the H700/H800 models with 1 GB of NVRAM on them, and comes as part of a certain firmware level. The feature will also only work with certain SSDs from Dell, so you can’t plan to just cram a cheap Intel X-25 in there (which is unfortunate, in my opinion). But you can use some of the cheaper Dell SATA SSDs (as opposed to the expensive-but-fast SAS ones), so that isn’t as bad. And, just to be clear, it won’t cache SAN/iSCSI data, only data that is stored on that particular H700 or H800.
Regardless, with Dell boasting 76% performance improvement for databases with CacheCade enabled I think it’ll be really cool for anything using local disk. Especially so for small & standalone VMware environments and FreeNAS & Gluster implementations running on Dell hardware.