xenial (8) flashcache_setioctl.8.gz

Provided by: flashcache-utils_3.1.3+git20150701-2ubuntu3_amd64 bug

NAME
       flashcache_setioctl - Set I/O behavior for special process in flashcache


DESCRIPTION
       The  flashcache_setioctl command can be used to set/remove a process from flashcache blacklist/whitelist,
       or clear flashcache blacklist/whitelist.


SYNOPSIS
       flashcache_setioctl (-c | -a | -r) (-b pid |-w pid) ssd_devname


OPTIONS
       -c     Clear blacklist/whitelist

       -a     Add to blacklist/whitelist

       -r     Remove from blacklist/whitelist

       -b     Operate on blacklist

       -w     Operate on whitelist


FLASHCACHE CACHE POLICY
       Flashcache can be put in one of 2 modes - Cache Everything or Cache  Nothing  (dev.flashcache.cache_all).
       The defaults is to "cache everything".

       These 2 modes have a blacklist and a whitelist.

       The  tgid  (thread  group id) for a group of pthreads can be used as a shorthand to tag all threads in an
       application.  The tgid for a pthread is returned by getpid() and the pid  of  the  individual  thread  is
       returned by gettid().

       The algorithm works as follows :

       In "cache everything" mode, 1) If the pid of the process issuing the IO is in the blacklist, do not cache
       the IO.  ELSE, 2) If the tgid is in the blacklist, don't cache this IO.  UNLESS 3) The particular pid  is
       marked as an exception (and entered in the whitelist, which makes the IO cacheable).  4) Finally, even if
       IO is cacheable up to this point, skip sequential IO if configured by the sysctl.

       Conversely, in "cache nothing" mode, 1) If the pid of the process issuing the IO  is  in  the  whitelist,
       cache  the IO.  ELSE, 2) If the tgid is in the whitelist, cache this IO.  UNLESS 3) The particular pid is
       marked as an exception (and entered in the blacklist, which makes the  IO  non-cacheable).   4)  Anything
       whitelisted is cached, regardless of sequential or random IO.


SEE ALSO
       flashcache_create(8)

       README and other documents in /usr/share/doc/flashcache-utils

       The     flashcache     source     code     and    all    documentation    may    be    downloaded    from
       <https://github.com/facebook/flashcache/>.


AUTHORS
       Flashcache is developed by Mohan Srinivasan <mohan@fb.com>

       This man page was written by Liang Guo <guoliang@debian.org> for Debian GNU/Linux (but  may  be  used  by
       others).