network maint.

[Hanry Zhou]

We will have a time frame for network maintenance and during which all system LAN connections will be gone. I don't think we should shutdown systems in this time frame. (is this right?). My questions, what I should do when LAN connections come back, and any other concerns I should consider?



Thanks,
Hanry

[Sridhar Bhaskarla]

Hi Hanry,

There are two cases when you would be concerned about network outages.

1. If you have serviceguard. In this case, you would want to halt the packages and shutdown the cluster.
2. If your applications are too network sensitive. Some applications can go crazy if they can't find the network. In this case, you may want to shutdown your application.

Once the maintenance is done, you should get your connectivity back automatically. If not, you can simply reset the network interface (using lanadmin command). You do not need to shutdown the servers.

-Sri

[Ron Cornwell]

I have never attempted to leave a system up while all network connections go down. Thing you may have problems with are NFS and sendmail. These two apps rely heavy on the network/ DNS and something may happen if mail tries to get sent or NFS attempts to get to a mount. Also ntp will give you errors if configured.

[Hanry Zhou]

Ron,

Thank you for the message.
Can you please let me know the details what ntp error will be?

[Hanry Zhou]

Anybody else?

[Pete Randall]

NTP will complain about not being able to contact it's time servers, but should sync back up fine once network connectivity is restored.


Pete

[Steven E. Protter]

Normally, you should have no problems other than the Serviced Guard issues noted above.

If total loss of network causes problems on your boxes, you might want to look into HP drivers for your NIC's or the NIC hardware. When a total loss of network service killed one of my D boxes a few times, we started an investigation that led to us replacing the NIC.

If you run databae applications, and there are a lot of open sessions, ie users not logging out when the network goes down, this could cause problems.

In general, when there is a planned network outage, I have operations bring the machines down to run level 1 or 2 depending on the circumstances and bring them up after the mainteance. This kicks out database users and reduces the possibility of a bad Monday with application/database problems.

SEP