Using an SSD as a cache device

Running SSD’s in RAID can get very expensive very quickly.  A more cost effective solution is to have a disk RAID and use an SSD as a cache.  I’m not sure if any of these are production ready but all are worth watching:

Abandoned Projects:

Bcache: Caching beyond just RAM


  1. Bcache isn’t production ready, but it’s getting closer 🙂 I should have a beta version up within a week, ought to be suitable for desktop use provided you have backups. More than happy to answer any questions about it.

  2. I am running flashcache on my home server, 60Gb of SSD caching a RAID5 array of 3x2Tb hard disks.

    Ubuntu server, 2.6.38-11.

    Works well in write-through.

    In write back the write-backs never seem to happen, even if I take the maximum dirty seconds parameter right down. Then when I rebooted my machine, kernel panic. Haven’t isolated it further.

    Moral : stick to write-through for the moment.

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