Date: Tue, 6 Feb 2001 10:03:48 -0800 (PST) From: Matt Dillon <dillon@earth.backplane.com> To: Poul-Henning Kamp <phk@critter.freebsd.dk> Cc: Charles Randall <crandall@matchlogic.com>, Dan Phoenix <dphoenix@bravenet.com>, Alfred Perlstein <bright@wintelcom.net>, Jos Backus <josb@cncdsl.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: soft updates and qmail (RE: qmail IO problems) Message-ID: <200102061803.f16I3m262539@earth.backplane.com> References: <36239.981482344@critter>
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:> with fsync(), so softupdates is not going to be too much worse then
:> other FS's.
:
:Actually, if you don't use fsync you do loose more work with
:softupdates than if you use plain UFS.
:
:Softupdates can delay directory updates which plain UFS will runs
:synchronously, and consequently you can loose stuff you throught
:you had.
:
:--
:Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
Yes, that's true. Except if you crash in the middle of doing significant
directory updates, especially when you are deleting AND creating files
in the same directory at a high rate, there's a good chance that fsck
will blow the entire directory away as being corrupt with a normal UFS
mount. The synchronous metadata updates that a normal UFS mount will
do only reduces the probability of significant loss of data for
*LIGHTLY* treaded directories. Any directory under heavy use ... well,
softupdates or a log structured filesystem coupled with judicious
fsync() use is your only real choice.
-Matt
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