Subject: Re: More async ffs -o async?
To: Jaromir Dolecek <jdolecek@netbsd.org>
From: Lennart Augustsson <lennart@augustsson.net>
List: tech-kern
Date: 10/14/2002 22:39:02
Yes!  If we could incorporate those changes it would be great.
I've noticed in the past the our async is not as fast as Linux ext2fs.

    -- Lennart

Jaromir Dolecek wrote:

>I noticed some old change in FreeBSD tree, which made async mounted
>filesystems to do even less stuff synchronously, thus speed metadata
>writes up to linux ext2fs level (at least so the commit log claimed).
>
>Would we be interested in such a change in our tree? Asynchronous
>filesystems would be even more likely to lose data in case of
>system failure, but the speed advantage might be worth the risk.
>Asynchronously mounted filesystems are not meant for important
>data anyway.
>
>The changes I noticed are these:Num
>
>dyson       95/11/05 13:01:17
>
>  Modified:    sys/kern  vfs_syscalls.c
>               sys/ufs/ufs  ufs_readwrite.c
>               sys/ufs/ffs  ffs_inode.c
>  Log:
>  Make MNT_ASYNC more effective for UFS.  It should not be too much more
>  dangerous than the original MNT_ASYNC.  There might be some minor
>  security considerations due to data writes not being posted as promptly
>  as before.  Meta-data operations are still not quite as fast as Linux.
>
>and 
>
>FreeBSD ufs/ufs/ufs_lookup.c rev 1.8: """
>This commit causes UFS to perform at Linux EXT2FS metadata rates.  After
>earlier discussions with DG, and a recent email exchange with SEF, I
>decided to allow UFS to run wide-open on an experimental basis.  We
>will probably support eventually multiple async modes, and this is
>the fastest the we can expect.  Just use the -o async flag on the
>UFS mount.  Good luck...
>"""
>
>Jaromir
>  
>