Hi All,

We have some very high utilization servers and it seems that over time ssh'ing into them slows down more and more. I check the memory and utilization and that looks good and when I restart the responds very fast even during heavy periods but after a week or two it slows down more and more. The weird thing is that is seems to slow down creating the shell environment, when I login it I get the username and password prompts pretty fast and it comes back right away with a authenticated but then it just sits there waiting for the command prompt.

I restarted xinetd, network and sshd and none seem to improve it but as I mentioned it seems to be the shell that takes a while to respond and not the services.

Any ideas?

Thanks.

what is the load on the box? any interesting main offenders in "top"?

The load CPU load is not high, it hovers from 1-20%. With the servers that seem to have this issue there is a lot of disk access, in fact most of utilization is via disk not CPU. Running top there do not seem to be any big offenders, in fact there are not really any offenders at all. At least according to top and free this server should respond very fast.

FYI, forgot to mention the OS, it is SLES 10.2 64 Bit for all the servers that have the issue, really only 3-4 servers have the issue.

Thanks

Can you clarify what this 1-20% value is? Is this same data as from the "uptime" command? Are you swapping data to disk a lot? (free -m)

The only time things like ssh "oddly" slow down tend to be things like DNS reverse lookup timeouts, but you say you're totally past the ssh relevant stages before you notice anything? a few -v's on your ssh command might prove that even further. Doesn't sound like too much to get hold of. nothing in /var/log/messages or /var/log/secure?

Does it only take a while to get to the prompt, or does the connection stay slow all the way?

I once had an nss-related issue (nss-ldap) where it took very long to get to the prompt, after ssh was ok (motd had been replaced, but prompt took another ~20 secs). -- I think it was the lookup for the username in the prompt that took so long.