topic Re: CLOSE_WAIT status in Operating System - HP-UX

CLOSE_WAIT status

Marco_67 — Fri, 22 Apr 2005 02:26:18 GMT

Hello,
I'm having problem on a server where is installed an application using the nfsserv process that in certain conditions went into freeze status.
During that time if I check the network connection by using the netstat -na I can see many connection in CLOSE_WAIT status.
The only way to get rid of that status and make the application working again is to restart the nfsserv process. Stating to HP support the server is ok and all necessary patches are installed.
Any clue, suggestion...?
Thank you
Marco

Re: CLOSE_WAIT status

Fred Ruffet — Fri, 22 Apr 2005 02:38:32 GMT

What are those conditions ? Does the distant host becomes unreachable ?

Regards,

Fred

Re: CLOSE_WAIT status

Henk Geurts — Fri, 22 Apr 2005 02:49:27 GMT

hi Marco
looks like you need the ndd parameter:
tcp_discon
however be carefull with this parameter...

check out other links about this subject:
search for "close_wait" in the forum discussions and you'll find lots of appropriate threads.and fully explained answers.

regards.

Re: CLOSE_WAIT status

Andrew Cowan — Sat, 23 Apr 2005 12:19:13 GMT

Is the server very busy, IO timeouts can be caused when there too many inbound comms sessions, or the server is starved of memory. I would start by doing some performance checks on the NFS server.

Next test the latency of the network using ping, traceroute, etc. Try to determine if you are dropping packets and/or experiencing timeouts. If this is the case start looking at switches and routers, and if there are any faulty LAN cables.

Re: CLOSE_WAIT status

rick jones — Sat, 23 Apr 2005 15:17:44 GMT

tcp_discon is an extreme kludge and should only be used in extreme circumstances.

CLOSE_WAIT means that the remote has sent this end a FINished segment, and we have ACKed it and sent notification up to the application. TCP is now waiting for the application to call shutdown and/or close.

If CLOSE_WAIT persists for an appreciable length of time, it indicates a bug in the nfsserv application.