Software SSD Cache Implementation For Linux?
Annirak writes “With the bottom dropping out of the magnetic disk market and SSD prices still over $3/GB, I want to know if there is a way to to get the best of both worlds. Ideally, a caching algorithm would store frequently used sectors, or sectors used during boot or application launches (hot sectors), to the SSD. Adaptec has a firmware implementation of this concept, called MaxIQ, but this is only for use on their RAID controllers and only works with their special, even more expensive, SSD. Silverstone recently released a device which does this for a single disk, but it is limited: it caches the first part of the magnetic disk, up to the size of the SSD, rather than caching frequently used sectors. The FS-Cache implementation in recent Linux kernels seems to be primarily intended for use in NFS and AFS, without much provision for speeding up local filesystems. Is there a way to use an SSD to act as a hot sector cache for a magnetic disk under Linux?”