Is there software for Linux to use an SSD as disk cache? I believe that Sun does something like this with ZFS, though not sure. A quick search provides nothing suitable. The goal would be to put frequently requested files on the SSD on-the-fly. Since the SSD has more capacity than RAM for less money and better performance than hard disk, this should provide an efficient performance boost.
Facebook recently released a module for the Linux kernel called 'FlashCache' which can do exactly this:
Have you looked into Bcache? http://bcache.evilpiepirate.org/
I realize this is an old topic, hope this helps anyone else who might have arrived here like me with an ssd cache question.
I don't think there's a simple way to do this on Linux yet. ZFS is available as a userspace filesystem, but it's not very good. Some ZFS clones are on their way, but as far as I know nothing is ready for production.
Perhaps you could consider a BSD with ZFS?
With SUN's ZFS, SSDs can be used as L2ARC cache , using the zpool add cache command:
A device used to cache storage pool data. A cache device cannot be cannot be configured as a mirror or raidz group. For more information, see the “Cache Devices” section.
I know nothing similar with Linux filesystems. I don't know if it would be suitable, but one thing you may try would be to add swap on SSD and tune the `swapiness' Linux kernel parameter (sysctl vm.swapiness)
protected by Michael Hampton♦ Apr 25 '14 at 4:48
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