freshmeat: Tired of fscking? Try a journaling filesystem!
Feb 18, 2001, 19:30 (5 Talkback[s])
(Other stories by Philipp Tomsich)
Re-Imagining Linux Platforms to Meet the Needs of Cloud Service Providers
"Waiting for a fsck to complete on a server system can tax
your patience more than it should. Fortunately, a new breed of
filesystem is coming to your Linux machine soon. Journaling
filesystems maintain a special file called a log (or journal), the
contents of which are not cached. Whenever the filesystem is
updated, a record describing the transaction is added to the log.
An idle thread processes these transactions, writes data to the
filesystem, and flags each processed transaction as completed. If
the machine crashes, the background process is run on reboot and
simply finishes copying updates from the journal to the filesystem.
Incomplete transactions in the journal file are discarded, so the
filesystem's internal consistency is guaranteed."
"This cuts the complexity of a filesystem check by a couple of
orders of magnitude. A full-blown consistency check is never
necessary (in contrast to ext2fs and similar filesystems) and
restoring a filesystem after a reboot is a matter of seconds at