Stasis' default log implementation ("filePool") creates a directory
full of 64MB log "chunk" files. Synchronously extending these files
one entry at a time is extremely expensive, as the filesystem must
repeatedly update its metadata. The "preallocate_log" utility in this
directory creates a Stasis log directory, and fills it with some
number of empty log chunks. It is safe to run this utility against an
existing Stasis log directory, but Stasis will not use the new chunks
until it is restarted. Also, although it is safe to mix and match log
chunk sizes, Stasis will continue to use its compiled-in size, wasting
the end of overly large chunks, and incrementally extending undersized
ones.
preallocate_log usage:
The first parameter is an integer, and specifies the number of log
chunks to be created. The second parameter is the name of the Stasis
log directory, and defaults to "stasis_log", the current default name.
The third parameter is the log chunk size, in the format extended by
dd's "bs" option (eg: 64MB, 1GB, and so on).
delete_log usage:
This script renames all of the files in a log directory so that they
end in "~". This will cause Stasis to reuse the files, but ignore
their contents (which avoids the cost of re-creating them).
