On Sun, Feb 03, 2002 at 02:41:52AM +0100, Matthias Andree wrote:
> Not really. BSD-softupdates aware code is safe with Linux 2.4's reiserfs
> or ext3fs, but not ext2fs (which needs -o sync).

I use ext3fs. But link(2) on ext3fs is still be done asynchronously.
This is explain why I got less than 1000 mails on my maildir.

Your suggestion to add fsync() call after link() do the trick.
I did the test again. Following your suggestion, I use this patch:

*** maildir.c Tue Nov 27 22:43:47 2001
--- maildir.c- Sun Feb 3 09:49:34 2002
***************
*** 80,85 ****
--- 80,86 ----
      VSTRING *why;
      VSTRING *buf;
      VSTREAM *dst;
+ VSTREAM *new;
      int mail_copy_status;
      int deliver_status;
      int copy_flags;
***************
*** 145,150 ****
--- 146,156 ----
                      || (make_dirs(curdir, 0700), make_dirs(newdir, 0700)) < 0
                      || sane_link(tmpfile, newfile) < 0)) {
                  vstring_sprintf(why, "link to %s: %m", newfile);
+ mail_copy_status = MAIL_COPY_STAT_WRITE;
+ }
+ if ((new = vstream_fopen(newfile, O_RDONLY, 0)) &&
+ (fsync(vstream_fileno(new)))) {
+ vstring_sprintf(why, "sync %s: %m", newfile);
                  mail_copy_status = MAIL_COPY_STAT_WRITE;
              }
          }
> Mount with -o sync if that bothers you. -o sync has only minor impact
> compared to the impact the ext2 -> ext3 switch has.

I didn't noticed any difficulties while migrating our mailserver
from ext2 -> ext3. Yes, I use ext3fs for postfix on our production
machine, days before ext3fs being accepted as an officially supported
fs on linux-2.4.x

I did chattr -S on postfix's queue, and got throughput about 5-6 faster
compared with while make directory operations synchronously (ext3fs).
Indeed, I got the speed comparable with ext2fs + write cache enabled.
My God!!! (note: I done the test *not* on any production machines).

I noticed that qmgr using unlink() for removing already delivered
queue file. It's mean that on asynchronous directory operation there is
possibility that a message would be delivered more than once. It's okay
(I think) as long as it won't lose any message :-)

Regards,

P.Y. Adi Prasaja

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