Flashcache uses 3 utilities for creating,loading and destroying cache.
1, flashcache_create
2. flashcache_load
3, flashcache_destroy
flashcache_create –> Create a new flashcache volume.
usage: flashcache_create -p back|around|thru [-s cache size] [-w] [-b block size] cachedevname ssd_devname disk_devname
-p : cache mode (writeback/writethrough/writearound).
-s : cache size. Optional. If this is not specified, the entire ssd device
is used as cache. The default units is sectors. But you can specify
k/m/g as units as well.
-b : block size. Optional. Defaults to 4KB. Must be a power of 2.
The default units is sectors. But you can specify k as units as well.
(A 4KB blocksize is the correct choice for the vast majority of
applications. But see the section “Cache Blocksize selection” below).
-f : force create. by pass checks (eg for ssd sectorsize).
-w : write cache mode. Only writes are cached, not reads
-d : disk associativity, within each cache set, we store several contigous
disk extents. Defaults to off.
2, flashcache_load : Load an existing writeback cache volume. This is not needed for writethrough/writearound
usage : flashcache_load ssd_devname [cachedev_name]
For writethrough and writearound caches flashcache_load is not needed; flashcache_create
should be used each time.
3, flashcache_destroy : Destroy an existing writeback flashcache. All data will be lost !!! .For writethrough and writearound caches this is not necessary.
usage : flashcache_destroy ssd_devname
vishnulinux 