John,
A few things I would look at:
1) What is the MSS value that is passed between the servers during the
initial TCP setup?
2) What is the value of the MTU on the servers?
3) Are there any name resolution issues? I have seen Solaris boxes keep
trying to resolve the DNS name of a client station and have extremely
slow network performance as a result.
4) Are there any "weird" TCP options being negotiated such as Selective
ACK or Windows Scale? Since these options aren't often used there may
be a bug in a servers TCP stack if these options are negotiated at
startup.
5) Have you checked the speed and duplex settings on the Solaris box?
In any case, a sniffer should tell the story. Just running snoop on the
Solaris box will probably give you the info you need.
HTH,
Kent
On Wed, 2003-07-16 at 11:57, John Neiberger wrote:
> We have a Windows server connected to a 6513 at 100/Full that does nightly
> backups (about 20GB) to a Solaris server connected to the same switch via
> gigabit ethernet. Prior to a recent upgrade the Windows server could upload
> approximately 5MBytes/s to the Solaris server. The Solaris server was
> replaced with much faster hardware and the OS was upgraded from Solaris 8
to
> Solaris 9. Novell servers doing backups to this server have continued to
> upload at about the same speed as before, while other Solaris servers seem
> to be uploading faster than before.
>
> The weird thing is that the Windows server uploads have dropped in speed by
> about 80%! We now see only about 1MB/s. This drop was seen on all Windows
> servers doing backups to this Solaris server. My guess is that there is
some
> funky issue with TCP between Windows and Solaris 9. I'm going to capture
> some transfers to see if I can spot the problem.
>
> Any ideas on what to look for right off the bat? Any tips from anyone who
> has seen this sort of thing before?
>
> Thanks,
> John
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