Veritas-bu

[Veritas-bu] Slow Performance of Restore

2002-04-11 10:26:02
Subject: [Veritas-bu] Slow Performance of Restore
From: Dave.High AT veritas DOT com (Dave High)
Date: Thu, 11 Apr 2002 07:26:02 -0700
Hi Phil, 

Typically a half duplex NIC runs at between 500 - 800Kb per second depending
on your machine and network. At 500Kbps, you are looking at about 1.8 Gig
per hour. Sometimes Windows machines at half duplex are even slower than 500
Kbps by the way. I have seen rates of 200 - 300 Kbps.. 

It is highly recommended that the NIC be forced to 100Mbit both at the card
level, and at the switch level and never, ever use auto negotiate. You would
be surprised how many times I have gone onsite to troubleshoot slow backup
rates only to have the network guy assure me that Auto Negotiate works just
fine, then I have to prove to them that it is stuck in Half Duplex... this
usually takes about two days to convince them to double check and test, and
it usually clears up the problem.  

Anyway, get the card set to 100Mbit full and retry the restore. You should
be able to do between 2 - 4 Megs per second. Use Perfmon to look at NIC
rates while it is running, or use the Unix Activity Monitor (Job Monitor) to
see how fast the backup is running. You should get nearly the same speed on
restores (depending on Multiplexing settings) as you do on backups. 

Other than that, the restore information from NBU is really limited. This
has been a pet peeve of mine for the longest time. NBU 4.5 addresses this
issue somewhat, but the information is still not as full as the backup
information. 

d. 

__________
dave high
VERITAS Enterprise Consulting
702.683.7733
 
Unix IS user friendly, it's just VERY picky about who it chooses as friends
 

> -----Original Message-----
> From: Weber, Philip [mailto:Philip.Weber AT egg DOT com]
> Sent: Thursday, April 11, 2002 5:34 AM
> To: 'veritas-bu AT mailman.eng.auburn DOT edu'
> Subject: [Veritas-bu] Slow Performance of Restore
> 
> Hi,
> 
> I am running a restore of an NT client, approx 110 Gb expected; over the
> last 8 hours it has done 10 Gb which seems a tad slow.  Can anyone offer
> any
> hints on how I might troubleshoot this e.g. to check throughput, see how
> much is remaining, or improve performance in the future?  I thought I had
> seen this topic discussed recently on the list but can't find it on the
> archives.
> 
> ...
> 
> Since I started writing this email I've discovered that the NT client has
> it's 100 MB interface set to Half-Duplex which I guess is what is causing
> the problem.  My other questions stand, though, is there any source of
> information on restore progress?
> 
> thanks, Phil
> 
> PS Solaris 2.6 master & media servers with 1000 MB interfaces, L700 with
> DLT
> Drives.
> 
> Phil Weber
> IT Infrastructure Unix Systems Engineer
> 
> Phone: 01384 26 4136
> Mobile: n/a
> 
> 
> 
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