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Re: postfix and ext3

Alex Kramarov wrote:
> here is a table of messages (34K personalised messages) sent per minute on
> different modes :
> ext2 : 417
> ext2 (chattr-S) : 600
> ext3 : 80
> ext3 (chattr-S) data=journal : 430
> ext3 (chattr-S) data=ordered : 370

Interesting, thanks.

The way to get high performance with ext3 is to have lots of
worker threads, each writing into different directories.
This way you get a lot of parallelism and you should get speedups of
ten-times or better.

But with a single process doing the work, or with all the work
happening in the same directory there's not a lot of gain.

chattr +S is fairly broken at present - for newly-created files
it does a sync for every 4k written.   That can easily be changed
to a sync-per-write(), which can speed up large-file writes by
a factor of up to ten, usually much less.

>From the pending-patch-pile:

--- linux-2.4.18-pre8/fs/ext3/inode.c	Tue Feb  5 00:33:05 2002
+++ linux-akpm/fs/ext3/inode.c	Wed Feb  6 23:40:48 2002
@@ -581,8 +581,6 @@ static int ext3_alloc_branch(handle_t *h
 			parent = nr;
-		if (IS_SYNC(inode))
-			handle->h_sync = 1;
 	if (n == num)
 		return 0;


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