Can't mount partitions with soft-updates enabled with async option

Giorgos Keramidas keramida at
Sat Jun 18 20:34:45 GMT 2005

On 2005-06-18 23:19, Lefteris Tsintjelis <lefty at> wrote:
> I am not sure if I do something wrong here or it is suppose to work that
> way but the async option doesn't seem to work for partitions that have
> soft-updates turned on.

Why would you want to do that?

Soft-updates already provides most of the benefits of an async mount plus some
extra goodies, like never leaving the filesystem in an inconsistent state.

> Can someone please clarify the difference and if the speed difference
> (if any) is significant when using the async option instead of the
> soft-updates for cases such as the /usr/obj or as a squid data
> storage? Is async preferred over soft-updates when data loss is not a
> big issue?

A speed comparison can be found in "The Design and Implementation of the
FreeBSD Operating System".

If I'm reading the relevant text correctly, then filesystems softupdates are
slightly slower than async mounted filesystems and a hell of a lot faster than
synchronous mounts without softupdates.

The speed gain of mounting a squid cache as async shouldn't really be that
big, but the guarantees of avoiding data loss when a filesystem is mounted
with softupdates are too big to ignore :-)

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