Thanks
Paula

Vernon Harris wrote:

Hi Paula,
If you haven't already done so, take a look at the attached zfs tuning guide.  
There have been
some requests for enhancement to sun to fix this issue. But in the interim you 
may want to
check this out.


http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide




----- Original Message ----
From: Paula Ehn <pehn AT CC.UMANITOBA DOT CA>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Sent: Monday, April 6, 2009 11:36:48 AM
Subject: [Networker] backup of zfs file system poor performance

Hi gang,

I've got a backup performance problem on our mail server caused by the way zfs 
uses memory.

Backup server is Networker V7.4.4 and Solaris 10 (no zfs yet) and the mail 
server is running Networker client SW v7.4.2 and Solaris 10 using a zfs pool on 
iSCIS luns for the mail store that is cut into 6 partitions. Each file 
partition is around 150GB and growing.  The mail server is running sendmail and 
cyrus. One of these mail partitions is taking all day and some over 26 hours to 
backup full. A similarly sized ufs file system takes a couple of hours to 
backup up.

We've identified the culprit at the zfs ARC memory cache on the mail server. 
Every read (and in the case of backups the whole file system) gets read into 
this ARC cache.  This is slowing down the backups as well as causing a 
performance hit on our mail server with some portion of the mail backups 
running during the day now.  We've added more memory to the mail server to 
combat this problem but it's still not enough to compensate for the backup hit.

For the record, I did not choose to use a zfs file system on the mail server, 
but I do have to back it up in such a way as I can do individual file restores.

Is anyone else seeing this problem? Are there any other options for backing up 
a zfs file system using Networker other than backing it up direct via the 
client? This mail store does have a few zfs snapshots as well but they reside 
on the same file system so backing those up instead of the working file system 
will not give me any performance increases.

Thanks
Paula
--  -----------------------------------------------------------------
| Paula Ehn  VE4MHZ/VE4HZ                    Room E3-628 EITC     |
| Unix System Administrator            pehn AT cc.umanitoba DOT ca |
| Academic Computing and Networking          (204)474-7849        |
| University of Manitoba                    Fax: (204) 474-8534  |
-----------------------------------------------------------------

To sign off this list, send email to listserv AT listserv.temple DOT edu and type 
"signoff networker" in the body of the email. Please write to networker-request 
AT listserv.temple DOT edu if you have any problems with this list. You can access the 
archives at http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

--
 -----------------------------------------------------------------
| Paula Ehn  VE4MHZ/VE4HZ                    Room E3-628 EITC     |
| Unix System Administrator                  pehn AT cc.umanitoba DOT ca |
| Academic Computing and Networking          (204)474-7849        |
| University of Manitoba                     Fax: (204) 474-8534  |
 -----------------------------------------------------------------

To sign off this list, send email to listserv AT listserv.temple DOT edu and type 
"signoff networker" in the body of the email. Please write to networker-request 
AT listserv.temple DOT edu if you have any problems with this list. You can access the 
archives at http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER