From experience at a customer site, using Clasissical IP (CLIP) we were able
to
see about 12MB/s throughput, but through LAN Emulation (LANE) we only saw
about 4-5MB/s throughput. We ran into some issues dealing with IBM, Cisco and
HPUX and their ideas of how things should work. If all your ATM network
equipment
is from a single vendor, you'll save yourself a lot of problems when it comes
down
to debugging things. (Finger pointing is a VERY frustrating exercise when you
don't
care about blaming people, but just want to find a workable solution.) I
don't have
access to the computer, otherwise I'd let you know what AIX parameters were
set up on the card / interface etc. Setting 'thewall', 'tcp_sendspace',
'tcp_recvspace',
and 'sb_max' to largish values seemed to help (this is done using the 'no'
command
and changing the /etc/rc.net script under AIX).. Note that changing these
parameters
can have a large affect on memory usage, so you'll have to make sure that your
large values don't inadvertantly cause more pageouts. If this were to happen,
your
networking performance would improve, but your overall performance might
decrease
because you had to move important pages back from disk in order to process the
data. Performance tuning is all about metrics and patience, or more cynically,
moving
the performance bottleneck from one spot to another.
I would plan on about a week of a tuning exercise in order to get reasonably
good values. Tweak a paramater, measure the results for at least a day or two
in
order to be reasonably confident that you're seeing consistent behaviour, and
repeat until you replace the system. :)
As to the question of "Can I actually get 15MB/s transfer rates?", I think
that it's
a matter of how you count bits as well as what you're doing. For instance, the
transfer
rate from computer to computer might actually be close to 15MB/s from one ATM
stack to another, but could be completely bogged down from the TCP/IP / ATM
translation. As well, you're much more likely to get more accurate results
from large
transfers rather than from small transfers, as the effects of setup times
should be a much
smaller portion of the total transfer times.
On an R50 with 512MB of RAM and two ATM cards, reasonable CLIP performance
was obtained using:
if [ -f /usr/sbin/no ] ; then
# setting network options for ADSM server
/usr/sbin/no -o thewall=131072 -o sb_max=2097152 -o rfc1323=1 -o
tcp_recvspace=1048576 -o
tcp_sendspace=1048576
fi
These values were obtained under AIX 4.2.1 about a year ago, and only after
applying the latest ATM patches to both the AIX ADSM server and to the
HPUX clients. For more information on these parameters, see the 'no' man page,
or check out Frank Water's book "AIX Performance Tuning". I don't have the
latest version of Adrian Cockcroft's Solaris performance tuning guide, but the
network options can be explored under Solaris using the 'ndd' command. For
HPUX (this is from memory as my notes from last year aren't here) I think you
want to check out the (think think, think) mtune (?) command.
Good luck with your tuning exercises!
kells
"Any coincidence of opinion between myself and Mainland Information Systems Ltd
is exactly that. My $0.02 and two loonies will buy you any legally-obtainable,
caffienated beverage. :)"
Lauer Edouard wrote:
> Hello,
>
> First question: Is it native ATM that you're using or are you using CIP over
> ATM. If it's the second one you'll never get a performance of 15Mb/sec.
> We've also an ATM configuration and the most we get is 11Mb/sec by using
> CIP on ATM.
> Second question: Which remote hosts are you backing up. Microsoft or Unix
> servers and what OS?
>
> Regards,
> _________________ Lauer Edouard ____________________
> ______ Prod. informatique ____ Systhmes Ouverts ________
> __ * +352 4590 3889 __ * Edouard.Lauer AT bil-dexia DOT com __
>
> > -----Original Message-----
> > From: Jack Musselman [SMTP:musselman AT SIERRALLC DOT COM]
> > Sent: Thursday, June 24, 1999 1:44 AM
> > To: ADSM-L AT VM.MARIST DOT EDU
> > Subject: ADSM V3 and 3590 Performance Tuning on a J40
> >
> > I am currently backing up to a tape storage pool using an ATM 155mbps
> > ring.
> > I am not using a disk copy storage pool. I am backing up directly to
> > tape.
> > Currently, my average transmission rate is 2.2 MB/sec or roughly 7.6 GB
> > per
> > hour. IBM states that a 15 MB/sec rate is possible. Does anyone have a
> > performance tuning tips that can help me speed up the transmission rate?
> >
> > Thanks in advance!
> >
> > ==============================================================
> >
> > An electronic message is not binding on its sender.
> > Any message referring to a binding engagement must be confirmed in writing
> > and duly signed.
> >
> > ==============================================================
> >
>
> ============================================================
>
> An electronic message is not binding on its sender.
> Any message referring to a binding engagement must be confirmed in writing
> and duly signed.
>
> ============================================================
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