🚀 go-pugleaf

Ok, I've had a few nice chats with some of the readers of this group
and with our local SGI support line, who are currently off chasing the
fact that this has been reported to them before but they couldn't find
what had happened last time (what kind of help-desk software does the
support line use?)

Anyway it turns out that my SGI Indigos can only push files over NFS
at about 10 to 30 Kbytes/sec (after the patch mentioned below) while
all the rest of our machines (Sun/HP/Mac), can manage over
110Kbytes/sec (I have a large number of figures if you want them.)  I
got a set of patches from SGI for general network performance (a new
ethernet device driver), which improved performance a good deal, but
still didn't put it in the acceptable range.  After hitting my head
for a while and replacing transceivers and moving machines etc, I
watched the network with etherfind (great tool -- why don't SGI
provide it?) and spotted that the SGIs are waiting after each NFS
write for an acknowledgement from the server.  Our servers don't
acknowledge 'til the block is on physical disk (like normal machines),
so there is a huge wait.  This is as if the biod daemons are not
working (but we have four (4) running.)  On all the other machines in
the dept, if I have N biods then I don't see blocking 'til N+1
requests are outstanding.  The delays get worse when one is over a
high latency netwrok while other machines just cope.  What is worse is
that if the Acknowledgement reply is lost (as sometimes happens on
ethernets (it is UDP after all)), the SGI waits for 4.5 SECONDS before
retrying the send.  A few of those and the time really adds up.

I don't want to imply that SGI arn't dealing with this, but I was
hoping that someone else has seen this and knows the cure -- have I
messed something up with the biods or is this normal SGI behavour?

-- Jon Peatfield  (Unix network admin)

Jon Peatfield, Computer Officer, the DAMTP, University of Cambridge
Telephone: (+44 223) 3-37852     Mail: J.S.Peatfield@amtp.cam.ac.uk

To be consistent with DNS domain ordering, shouldn't news groups have
names like "admin.sun.sys.comp" not "comp.sys.sun.admin" ?  EMWTK
--
Jon Peatfield, Computer Officer, the DAMTP, University of Cambridge
Telephone: (+44 223) 3-37852     Mail: J.S.Peatfield@amtp.cam.ac.uk

To be consistent with DNS domain ordering, shouldn't news groups have
names like "admin.sun.sys.comp" not "comp.sys.sun.admin" ?  EMWTK