ADSM-L

Re: Long, long, long backup sessions

2001-08-24 13:11:44
Subject: Re: Long, long, long backup sessions
From: Gerald Wichmann <gwichmann AT SANSIA DOT COM>
Date: Fri, 24 Aug 2001 10:14:08 -0700
I've done some limited tests on an Win2k client where I created roughly
1.5 million 100KB files and backed it up with the 4.1.x client. After
the initial full backup, it took roughly 55-60 minutes to do a backup
due to the fact that it had to traverse the tree. This Win2K server box
was pretty slow. Pentium 500 cpu, 256MB ram.

Although this is unrelated to the problem, I then put on the 4.2.x
client and installed the TSM journaling service. Backup time went from
about an hour to about 5-7 minutes. A great savings for the NT/2k
platform.

If your system was able to match the earlier figure performance wise, I
would expect 8.3 million files to take roughly 3 hours to scan the
drive. Of course these are different platforms and my box had no load on
it at the time of the tests other then what TSM was doing.

Also that's only scanning the filesystem and not really sending much
over the pipe. Your report shows you backed up 2.83GB of data.

One obvious problem judging by your output is your network throughput.
It's horrible. Though as other's have pointed out there's probably more
to the problem then just that but it looks like you're only getting
about 10Mbps throughput. I would recommend you test your network
throughput independent of TSM by FTP'ing a reasonably sized file between
the client box and the TSM server to see what kind of throughput you
see. If it matches what TSM is getting, you probably have a network
issue (I've seen many times where AIX boxes set to auto-negotiate speed
on their NIC's don't perform well with particular switch/routers. The
solution is to force both the NIC and router to full duplex 100mbps no
auto negotiation). If it doesn't match what TSM is doing then perhaps
some client tuning would help.

At your report's network transfer rate of 522KB/s your 2.83GB of data
would've taken.. let see.. 522KB = 522,000 Bytes.. 2.83GB =
2,830,000,000 Bytes.. 2,830,000,000/522 = 5,421,455 seconds.. = 90,357
minutes.. = 1,505 hours.. = 62 days.. hrm that can't be right.

You sure it's finishing backups in 16 hours?

I would say looking at the numbers that your major problem is your
network throughput here.. NOT the number of files you're backing up.
Check with the FTP test above and check NIC/network settings. I bet your
problem lies there.

Gerald Wichmann
System Engineer
StorageLink
408-844-8893 (v)
408-844-9801 (f)


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