zfs flag denoting unclean shutdown?

Matthew Seaman matthew at FreeBSD.org
Wed Oct 2 18:14:00 UTC 2013

On 02/10/2013 16:34, Nikos Vassiliadis wrote:
> Is there a way to know if a zfs pool had an unclean shutdown?
> An attribute or maybe something during mount time similar to what ufs
> does (WARNING: / was not properly dismounted)?

Other than looking at the system logs for evidence of an abnormal
shutdown, no.  (Absence of anything in the logs is pretty good evidence
for the system falling over pretty hard... Usually something to do with
the power being turned off.)

However, due to the design of ZFS unclean shutdowns like this are
nowhere near as problematic as on UFS.  Basically, you're guaranteed
that what is written on disk is always consistent.  You might lose a few
transactions -- essentially the last few seconds of file system activity
-- but that doesn't usually make a great deal of difference after the
system reboots again.  Oh, yeah -- absolutely no time will be needed to
be spent cleaning and repairing filesystems: with ZFS, reboot after
crash is as fast as a normal reboot.



Dr Matthew J Seaman MA, D.Phil.
PGP: http://www.infracaninophile.co.uk/pgpkey

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