heavy NFS writes lead to corrup summary in superblock

Eric Anderson anderson at centtech.com
Fri Jun 9 12:27:55 UTC 2006


Oliver Fromme wrote:
> Mikhail Teterin <mi+mx at aldan.algebra.com> wrote:
>  > The FS is intended for very few very large files and was created 
>  > with "newfs -b 65536 -O1" (no softupdates).
> 
> Did you also increase the fragment size (-f option)?
> The default is 2048 bytes, and I wouldn't expect a b/f
> ratio of 32:1 to work very well.  In fact I'm surprised
> that you have so little problems.  :-)
> 
> If you intend to have very few very large files that are
> accessed sequentially most of the time, it is probably
> better to set both block and fragment size to the same
> value (e.g. 16k), essentially disabling fragmentation.
> You should also reduce the inode density by specifying
> a larger bytes-per-inode value (-i option), a typical
> value would be 262144 (2^18).
> 
> Carefully fiddling with the -g and -h options might also
> improve performance a bit, see newfs(8).

He should also use UFS2, and disable softupdates (if he really doesn't 
want them).  No reason I can think of to use UFS1, but that doesn't mean 
there isn't a bug lurking in UFS1.


Eric



-- 
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Eric Anderson        Sr. Systems Administrator        Centaur Technology
Anything that works is better than anything that doesn't.
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