Networker

Re: [Networker] Undesirable speed backing up to adv_file device.

2004-01-17 00:56:09
Subject: Re: [Networker] Undesirable speed backing up to adv_file device.
From: "Lemons, Terry" <lemons_terry AT EMC DOT COM>
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Date: Sat, 17 Jan 2004 00:55:34 -0500
Hi Matt

Remember that the data path when you clone is different than your backup
data path (to state the obvious).  When you back up, you are also limited by
your backup client's CPU, memory, disk speed and file system, system load,
NIC and other factors.  If your backup clients use relatively slow disks,
then that might be the limiting factor.

When I deal with problems like this, I like to diagram or write out every
step in path between the source disk to the target disk.  When that's done,
look at the speed of each item in the path, and you'll get to the worst
bottleneck.  Remove it, and the next-worst bottleneck becomes the current
bottleneck.

Hope this helps.
tl

-----Original Message-----
From: Legato NetWorker discussion [mailto:NETWORKER AT LISTMAIL.TEMPLE DOT EDU] 
On
Behalf Of Ungaro, Matt
Sent: Friday, January 16, 2004 5:38 PM
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: [Networker] Undesirable speed backing up to adv_file device.

Hello all,
        We have a Linux (Redhat 9) system running Networker 7. The hardware
is an Aberdeen (http://www.aberdeeninc.com) systems Backup Monster with 8
120GB hard disks in a RAID 5. I am first backing up all data to a 980GB
adv_file device that is a partition on the RAID formatted with ext3 (mount
options are rw,suid,dev,exec,auto,nouser,async,noatime,data=writeback). The
Backup Monster has 2 GigE interfaces, one I have in my internal network and
the other in my DMZ. When backing up clients on the internal network, I am
maxing out writing to the disk device at 11MB/s. For the DMZ, sometimes I
reach 8MB/s. After I finish backing up to disk, I clone all savesets to an
HVD Sun Storedge L9 library with an HP-Ultrium LTO drive. For that process I
am getting 15 MB/s, sometimes higher. Why is my disk backup so slow? The
system itself is a P4 with 512 MB RAM. I would think that I would get a much
higher write speed to disk than I am getting. I am also allowing 64
simultaneous target sessions to the adv_file device. Any tips on increasing
speed would be greatly appreciated. Thanks in advance!

Matt Ungaro (mjungaro AT capitolindemnity DOT com)
Network Specialist
Capitol Indemnity Corporation
4610 University Ave. Ste. 1400
Madison, WI  53705
Phone: (608)232-5654
Fax: (608)232-5671

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