Networker

Re: [Networker] Backup speed drop with 7.3.3 (nsmmd problem?)

2007-09-02 12:03:25
Subject: Re: [Networker] Backup speed drop with 7.3.3 (nsmmd problem?)
From: "Macina, Conrad" <Conrad.Macina AT PFIZER DOT COM>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Sun, 2 Sep 2007 12:00:01 -0400
Another possibility: What do you know about the file systems being
backed up when the speed drops? NetWorker (and most other backup
software) has problems with "millions of tiny files" save sets because
each file must be recorded in the index database, resulting in
considerable overhead on the host system. If that's the case, I'm afraid
there's no easy solution, other than block-level backups (SnapImage).

Conrad Macina
Pfizer, Inc.



-----Original Message-----
From: Brian O'Neill [mailto:oneill AT OINC DOT NET] 
Sent: Saturday, September 01, 2007 4:43 PM
Subject: Backup speed drop with 7.3.3 (nsmmd problem?)

[Argh...I spent gathering info and typing this message, and I think I 
see the issue...more info at the bottom]

This is a new setup, and I'm at a loss as to what's happening - 
wondering if someone else has seen something similar.

Server is a Dell 1850 running Red Hat ES4 (32-bit) and Networker 7.3.3 
with a PERC-connected RAID 5 array for adv_file storage.

Backup client is an older Dell 1750 running Red Hat ES4 (32-bit) with an

Adaptec ASR-2130S-connected RAID 5 set with a filesystem containing 
400GB of Oracle dump files. Only the dumps are being backed up. Client 
is 7.3.3.

Connection is via a private backup network, with a single gbit switch in

between. Both hosts have their adapters at 1000/full, and are not 
showing any errors (I don't have insight to the switch yet - it's 
managed by the people I'm setting up the backup for, and its the long 
weekend).

Things start off at a steady rate of 35MB/s, with perhaps peaks in the 
40MB/s range. Reasonable enough.

But at someone point - roughly an hour or about 140-150GB in to the 
backup, speeds suddenly drop to a VERY steady 146 +- 2KB/s. And with 
250GB to go, VERY unacceptable.

Any thoughts as to what might be the cause of this degradation?

New: Now I'm noticing that on the backup server that one of the nsrmmd 
processes is eating up CPU...is this the problem on 7.3.3 that I've been

hearing about? Is the only solution to downgrade to 7.3.2?

-Brian

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