Re: rsync on maildir

[Theodore Knab <tjk@annapolislinux.org>]

Thanks you helped me find the bottleneck. 
My server is always waiting on the IO.

Somebody told last year that I should not have maildir on a ext3
filesystem, now I understand why. It seems that heavy journaling can cause 
io waits.

If postfix is not waiting for the IO then something else is.

I am going to convert everything back to ext2 first chance I get.

Later I will move to xfs as a journaled filesystem. I think that 
xfs performs as good as ext2. 

tknab2@imap:~$ ps ax | grep ' D'
15 ?        DW   100:12 [kjournald]
105 ?        DW   101:37 [kjournald]
109 ?        DW   141:53 [kjournald]
112 ?        DW   128:32 [kjournald]
30746 pts/1    DN     0:00 /usr/bin/rsync -az --delete
	 /var/imap/mailarray/01201201
	 /remote_drive/live_backup/mailarray
	 --exclude .Trash

On 26/10/03 17:10 +0100, J.J. van Gorkum wrote:
> Hi,
> 
> When the slowdown occurs, try a ps -ax and look in the STAT colum...
> 
> if the rsync process has status D  rsync is waiting on IO (raid
> array)...
> 
> few ponters:
> 
> - look at the raid config... is it optimized (look at WT / WB mode)
> - try mounting the filesystem with the noatime option...
> 
> On Sun, 2003-10-26 at 14:00, Theodore Knab wrote:
> > I am using rsync to backup mail on a mail-server with 3000+ mail
> > accounts [only 1550+ are in use]. Using this command:
> > 
> > /usr/bin/rsync -a --delete /var/imap/mailarray /var/oldarray 
> > 
> > This mail server only receives about 2GB of mail per day. Rsync is run
> > without shutting down any services.
> > 
> > About half the time I run rsync the system slows down to the point that
> > mon starts sending me pages. To fix it, I have to log in, and kill the rsync
> > process.
> > 
> > Is there a more efficient way to run rsync without down time ?
> > 
> > Or should I be using something else for backups ?
> > 
> > After the last failure I ran rsync in dry-run mode and I got this error:
> > imap:~# /usr/bin/rsync -axn --delete /var/imap/mailarray /var/oldarray -T
> > /tmp --timeout=10
> > building file list ... 
> > rsync: writefd_unbuffered failed to write 4092
> > bytes: phase "send_file_entry": Broken pipe
> > rsync error: error in rsync protocol data stream (code 12) at io.c(515)
> > 
> > imap:~$ rsync --version
> > rsync  version 2.5.6  protocol version 26
> > 
> > file-system ext3:
> > raid-card:0
> > #system file-system and mail backup
> > /dev/sda5 on /var/oldarray type ext3 (rw,noexec,nosuid,nodev) []
> > 
> > raid-card:1
> > #mail storage
> > /dev/sdc5 on /var/imap type ext3 (rw,noexec,nosuid,nodev,usrquota) []
> > 
> > -- 
> > ------------------------------------------
> > Ted Knab
> > Chester, MD 21619
> > 
> > ------------------------------------------
> > 940216d6021602a41607166696c656c202778696368602d65616e637
> > 02940226c696e646c69702c6f667560256675627478696e67602a416
> > 0716e6563756e2a0
> -- 
> JJ van Gorkum                             Knowledge Zone
> If UNIX isn't the solution, you've got the wrong problem.
> 

-- 
------------------------------------------
Ted Knab
Chester, MD 21619

------------------------------------------
940216d6021602a41607166696c656c202778696368602d65616e637
02940226c696e646c69702c6f667560256675627478696e67602a416
0716e6563756e2a0