From: hamish@waikato.ac.nz
Newsgroups: bit.listserv.novell
Subject: Re: Arcserve performance questions
Date: 8 Oct 92 13:13:28 +1300
Organization: University of Waikato, Hamilton, New Zealand

In article <MAILQUEUE-101.921007102019.320@ace.acadiau.ca>, Paul Steele <paul.steele@ACADIAU.CA> writes:
> I am in the process of installing Arcserve on one of our servers.  So far, I
> am impressed with the package compared to our our old Maynard system.  One
> thing that did puzzle me though is the speed of remote backups (backing up
> another server from the main server).  I am only getting a throughput of 2300
> KB/minute, which is considerably slower that when I backed up a server from a
> workstation using the Maynstream software.  I would think that the NLM
> running on a server (in this case the server was doing nothing else than
> backing up) would get just as good performance as a workstation based backup
> scheme. The server has 1400 MB in 103,000 files.  The backup took 11.62 hours.
> The backup is to a 2.2 gig 8mm tape drive (the Maynard 2200HS).
> 
> What are other people's experience with remote backups using arcserve?
>

Well. I have a backup program written here, and had some consternation about
its speed until I did a little more testing and asking of questions on
compuserves NOVDEV forum. The figures I get backing up a remote server are
approx 70kb/sec reading a remote drive, while I can get up to 450kb/sec reading
a local drive without raising a sweat (Or local file server utilisation).

It turns out that netware servers do not use burst mode between themselves
(Even if both have the burst mode NLM's loaded), and they also suffer from the
small packet syndrome (It also seems to be irrespective of whether the large
packet NLM is loaded or not. I'm not entirely sure on this one as I only had
the demo version of this to try out). Therefore the communication between the
two server is much slower that that between a server and a workstation if using
things like burst mode NLM/shells etc.

The client side of NLM->Remote Server also seems to be a lot less efficient at
just transferring the info to the NLM than the shells in a workstation. Don't
ask me why, I don't know. What I do know is that here, with a PS/2-80 (16Mhz
with Adaptec SCSI), as a remote server, and a 486 33Mhz NW386 server acting as
a client end, the max thruput I can get is about 70-90kb.sec tops. Not exactly
a glowing performance. There is a little bit of extra overhead in the program
regarding saving the info read, but that is very small compared with the amount
of time spend waiting on the connection from the remote server (I ised watcom
profiler to test this. About 90% of the NLM's time was spent waiting for read's
to complete).

Oh yeah. The two servers are seperated by a cisco AGS+, with routing turned on.

Conversely I can read from the same server (The PS/2-80) from a DOS workstation
(286 or 386 with 16-bit card) at around 100kb/sec without breaking into a
sweat. The compiler was a different one too. Watcom C/386 vs Borland C2.0

Well. After all that. I still haven't come up with a solution. But at least I
know the problem. SOmebody (Hey novell you listening?) come up with a way to
make servers take burst mode to each other and we'll be away!

 
> ___
> Paul Steele, Network Services Manager              902-542-2201x660
> Acadia University, Computer Centre            FAX: 902-542-4364
> Wolfville, Nova Scotia, Canada, B0P 1X0  Internet: Paul.Steele@acadiau.ca
-- 
==============================================================================
|  Hamish Marson   <h.marson@waikato.ac.nz>                             OS/2 |
|  Programmer (n/5), School of Computing and Mathematical Sciences           | 
|  University of Waikato,                                                    |
|  Hamilton, New Zealand.                                                    |
|Disclaimer:  Anything said in this message is the personal opinion of the   |
|             finger hitting the keyboard & doesn't represent my employers   |
|             opinion in any way. (ie we probably don't agree)               |
==============================================================================
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