Networker

Re: [Networker] How to improve performance

2004-10-22 12:04:37
Subject: Re: [Networker] How to improve performance
From: Tony Skalski <ajs AT STOLAF DOT EDU>
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Date: Fri, 22 Oct 2004 11:03:37 -0500
I would fire up Ethereal (or snoop, or tcpdump with timestamps) to get a
good look at what is happening.

We used to see performance drop to the KB/s level and found that the
server was delaying the acknowledgement of data from the client until
there was more data to send to the client (a TCP optimization that works
poorly for one way data flows like backups). Check this on both the
client and the server. You'll typically be able to see the (default)
200ms delayed ack timer in action in a packet trace. Also increasing the
TCP window size will help, as mentioned.

Here is a good guide to TCP tuning on Solaris:

http://www.sean.de/Solaris/soltune.html

Here is some info for Windows tuning:

http://rdweb.cns.vt.edu/public/notes/win2k-tcpip.htm
http://www.microsoft.com/technet/itsolutions/network/deploy/depovg/tcpip2k.mspx

ajs
--
Tony Skalski
Systems Administrator
507-646-3227
ajs AT stolaf DOT edu
-------------------------------------------------------
St. Olaf College                   1510 St. Olaf Avenue
Information and                          Northfield, MN
Instructional Technologies                   55057-1097
=======================================================

Rahul Parasnis wrote:
I can defnitely lookup with this Drive allocation . But the I am having
only
one drive with 260 and one drive with 80 GB , that legato just starts one
seesion for it , which means legato start one session for one drive
regardles of it's size .

Moreover the same server was backup by Veritas backup exec much faster then
I am begining to believe that there sever design problem .

Backup speed goes to 40 mb /s to 256 kb/s .
regards,
- Rahul

From: "Fields, David" <David.Fields AT ACS-INC DOT COM>
Reply-To: Legato NetWorker discussion <NETWORKER AT LISTMAIL.TEMPLE DOT EDU>,
        "Fields, David" <David.Fields AT ACS-INC DOT COM>
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: Re: [Networker] How to improve performance
Date: Fri, 22 Oct 2004 10:26:39 -0400

As an experiment, try running a test backup by picking just one of
your big
filesystems, and then compare the time that it takes to run that backup
against your normal backups.

The reason I say do this is that you have to remember that unlike other
backup software, Legato starts up multiple streams so that it can make
the
best use out of the tape drive that it can.  However, you have to keep
some
stuff in mind.  For instance, if you have a server, with 3 drives,
defined
into one Raid-5 container, and then you create multiple "drives" within
that
container, all three drive are using the same spindles (disks).  If these
drives are big, and if you tell Legato to back up all 3 at the same time,
you can actually slow down your backup because the disks are being
overworked (disk thrashing).  I know you're using a SAN for this, but you
still might want to look to see how the particular drives you are backing
up
are actually configured within the SAN, as you could very easily have
multiple filesystems using the same physical drives.

If you were doing this over a Gig Ethernet network, then I would say
you're
possibly running into some other bottlenecks, such as TCP window size or
some other TCP setting, which can have a big effect on performance.
Windows
uses some very conservative network settings for Gig-E networks, and
it can
be very tricky trying to figure out the best configuration (I'm still
working on it actually..if anyone has any info on this, I would
appreciate
your input).  For instance, if you try to ftp from a Windows box over
a Gig
network, I rarely get over 20MB (Mega Bytes)/sec out of the network,
using
default settings.  However, if I change the TCP window size, I can
increase
that to almost 40 or 50MB/sec.  At that point, the PCI bus is likely to
start being a bottleneck.

Dave

-----Original Message-----
From: Legato NetWorker discussion
[mailto:NETWORKER AT LISTMAIL.TEMPLE DOT EDU] On
Behalf Of Rahul Parasnis
Sent: Friday, October 22, 2004 10:09 AM
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: Re: [Networker] How to improve performance

I am using Networker 7.1.2 .


>From: "Kuin, CNM" <CKuin AT WLZ DOT NL>
>Reply-To: Legato NetWorker discussion <NETWORKER AT LISTMAIL.TEMPLE DOT EDU>,
>         "Kuin, CNM" <CKuin AT WLZ DOT NL>
>To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
>Subject: Re: [Networker] How to improve performance
>Date: Fri, 22 Oct 2004 14:48:54 +0200
>
> > -----Original Message-----
> > I have recently installd new Networker Server on Solaris 9
> > with L180 of 8
> > Drives  .
> > Enviromment .
> >
> > Server Solaris 9 , V440  2 CPU 4 GB
> > Brocade Switch .
> > L180 and Lto-2 drives
> > Lp9000 HBA card on Solaris
> > LP10000 card on Windows 2000 and windows 2003 cluster DSN's  .
>Which version of Networker are you using?
>7.x has some improvements regarding backing up a high number of files.
>
>With regards,
>Cor.
>
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