If I/O performance is a concern, you may be interested in ZFS and Flashcache.
Specifically, ZFS' ZIL (ZFS Intent Log) and its L2ARC (Layer 2 Adaptive Read Cache) ZFS does run on Linux http://zfs-fuse.net Flashcache: https://github.com/facebook/flashcache/ Both of these techniques can use a pair of SSDs in RAID1 rather than a single SSD. On Oct 27, 2011, at 1:31 AM, Ed W wrote: > On 27/10/2011 03:36, Stan Hoeppner wrote: >> On 10/26/2011 4:13 PM, Patrick Westenberg wrote: >>> Hi all, >>> >>> is anyone on this list who dares/dared to store his index files on a >>> MLC-SSD? >> I have not. But I can tell you that a 32GB Corsair MLC SSD in my >> workstation died after 4 months of laughably light duty. It had nothing >> to do with cell life but low product quality. This was my first foray >> into SSD. The RMA replacement is still kickin after 2 months, >> thankfully. I'm holding my breath... >> >> Scanning the reviews on Newegg shows early MLC SSD failures across most >> brands, early being a year or less. Some models/sizes are worse than >> others. OCZ has a good reputation overall, but reviews show some of >> their models to be grenades. >> >> Thus, if you were to put indexes on SSD, you should strongly consider >> using a mirrored pair. >> > > I don't think you are saying that the advice varies here compared with > HDDs? I do agree that some SSDs are showing very early failures, but > it's only a tweak to the probability parameter compared with any other > storage medium. They ALL fail at some point, and generally well within > the life of the rest of the server. Some kind of failure planning is > necessary > > Caveat the potentially higher failures vs HDDs I don't see any reason > why an SSD shouldn't work well? (even more so if you are using maildir > where indexes can be regenerated). > > More interestingly: for small sizes like 32GB, has anyone played with > the "compressed ram with backing store" thing in newer kernels (that I > forget the name of now). I think it's been marketed for swap files, but > assuming I got the theory it could be used as a ram drive with slow > writeback to permanent storage? > > Good luck > > Ed W
