Login Taking Long time

[rana sarkar]

Whenever our primary DNS server is down or not reachable the login to our servers take a long time.
It takes long to prompt for passwords after providing username and giving enter.

even the cmviewcl returns the following:
[wb_server01] /home/admin > sudo /usr/sbin/cmviewcl
Password:
Last successful login for admin: Fri Apr 10 11:46:33 IST-5:30 2009
Last unsuccessful login for admin: Tue Apr 7 16:01:43 IST-5:30 2009
cmviewcl : Cannot view the cluster configuration.
Either this node is not configured in a cluster, user doesn't have
access to view the cluster configuration, or there is some obstacle
to viewing the configuration. Check the syslog file for more information.
For a list of possible causes, see the Serviceguard manual for cmviewcl.
[wb_server01] /home/admin >

[Ivan Krastev]

For slow logging add the following in the sshd config file:
UseDNS no

and restart the daemon.

For SG issue - add all nodes in /etc/hosts files at every node.

regards,
ivan

[Steven E. Protter]

Shalom,

When DNS server is down and you log in by name, login is going to be slow. To be sure this is the cause, try logging in by numeric ip address.

It will be fast, if I'm right.

The solution here is to use numeric ip when the DNS server is down or fix the DNS server.

Makes sense if you think about it. How can name to number resolution happen if there is no service.

You can bypass this with critical systems by including resolution in them in /etc/hosts and including files in /etc/nsswitch.conf configuration as an option. I like files to be first.

SEP

[UVK]

Greetings !!

Depending on the usage, I would add the hosts that I access often in /etc/hosts, as files are looked up for name resolution. Alternatively you can use named service on your unix server to act as a slave DNS to avoid. This is reduce the load on ur primary DNS and also slave works even if the primary DNS is down as it caches the DNS DB.

Regarding you cluster problem, do you face this issue only when DNS is down ? If yes need more info from cluster logs. If not you might need to check if cluster is configured on this server ?

Cheers,
UVK

[Steven Schweda]

> It takes long to prompt for passwords after
> providing username and giving enter.

> [...] try logging in by numeric ip address.
>
> It will be fast, if I'm right.

If the problem lay in the client's getting
the IP address of the server (from its name),
then I'd expect the slow part to be in the
initial connection, not something "after
providing username".

If, instead, the problem lies with the server
trying to get the name of the client (from
its address), then it won't matter how the
client specifies the server's address -- name
or number.

Also, if DNS is completely dead, and if the
server is not in the client's hosts file,
then the connection attempt would fail
completely, not merely be slow to get
established.

Hence, this common suggestion to try using
the IP address instead of the name is often a
complete waste of time. It would appear to
be so here.