Backup Problem

[KRFinch at dstsystems.com]

Stanley

I don't have a lot of experience with Veritas Netbackup, but if it's like
some of the other Veritas products I have been exposed to in years past,
the problem is probably with it rather than with the network.  My first
guess would be that the Veritas end of it is configured incorrectly, and
that there is some timeout setting that isn't set right.  If you are using
some Veritas agent to backup a live database, I'm about 90% sure that the
problem is with that agent.  We'll assume that isn't it, and we'll also
assume that all the obvious causes (power surges, full backup media, open
files, someone manually stopping the backup, a full swapfile, database
errors, hardware faults, inadequate memory, crashed processes, etc.) have
been ruled out as well.  If they haven't been ruled out, do so before you
blame the network; if you can get a partial backup, the network is probably
OK.

The next thing that I would do is take a look at the saturation on the
network segment that your Linux server is on WHILE the backups are timing
out.  If there is too much traffic, odds are the packets are getting
dropped by the network and they just aren't getting from the Linux box to
the Veritas one fast enough because of the interference.  The easiest way
to check the saturation is to take a look at the hub/switch collision
lights and see if they are going off like crazy, but using a software
diagnostic (like Ethereal or Shomiti) would probably be a better idea.  I
would guess that there are probably several nodes on the network being
backed up at the same time (all pushing a LOT of data), and that could be
the cause of the latency.  I've run into this problem myself on at least
one occasion -- all I had to do to solve it was stagger the backup times.

Getting on to your question, most 10/100 cards have an extra (or different)
connect light that goes on when they get a full 100Mb connection.  Most
hubs and switches behave in the same manner.  Check either one at any time
and see how fast you are connecting.  If you are in such a position that
neither one is giving you any indication, you can always plug into the
diagnostic port on the hub/switch and take a look from there.  If you are
using some of the fancy Cisco stuff out there, you can probably even take a
look at the port characteristics through a browser.

Here's hoping this helps!

Kevin Finch
Network Administrator
DST Systems, Inc.
816/435-6039
krfinch at dstsystems.com

                                                                                                    
                   
                    stanley.g.martin at mail.                                                          
                   
                    sprint.com                    To:     kclug at kclug.org                           
                   
                    Sent by:                      cc:                                               
                   
                    owner-kclug at marauder.i        Subject:     Backup Problem                       
                   
                    lliana.net                                                                      
                   
                                                                                                    
                   
                                                                                                    
                   
                    01/04/2002 09:01 AM                                                             
                   
                                                                                                    
                   
                                                                                                    
                   

First Post

I'm running RH7.1 on my server and I am experiencing a lot of trouble
getting my backups to work. My server is in a corporate Datacenter and
backups are controlled by a group that uses Veritas Netbackup.  Ever
since we installed this box, backups have never worked consistently.
Our network group has set up their switches to run at 100MB Full Duplex.
How can I make sure my NIC is running at this speed and if not, change
it?  The backup will run for a while and then time out.  I'm not saying
the problem is my network setting, but neither Veritas or the backup
group can come up with anything better.

Stanley G. Martin
Midwest Consulting Group
Sprint Platform & Strategy Mgmt
913.315.3133
Stanley.G.Martin at mail.sprint.com


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