On Wed Jul 25 2001 at 18:43:32 +0200, salo wrote:
> i would like to ask how possibly dangerous is using 'async' option to mounting
> disks (ffs, softdeps).
> 
> from mount(1) napage:
> 
> async       All I/O to the file system should be done asyn-
>             chronously.  In the event of a crash, it is
>             impossible for the system to verify the integrity of
>             data on a file system mounted with this option.  You
>             should only use this option if you have an applica-
>             tion-specific data recovery mechanism, or are willing
>             to recreate the file system from scratch.
> 
> could it cause unrecoverable damage to filesystem or could i only lost data
> not currently written to disk?

I guess using -o async it's entirely possible to get the filesystem
metadata easily into a shape from which it can't be recovered. Linux
does (did?) this by default with ext2, and it was very easy to get that
into a totally wacky state.

> is there any relevant profit using 'async' option in speeding up filesystem
> operations?

Yes, there is if you know what you are doing. But I don't think it can
be used together with softdeps anyways.

-- 
Antti Kantee <pooka@iki.fi>          v          Of course he runs NetBSD
http://www.iki.fi/pooka/             i            http://www.NetBSD.org/