NFS Client hang squashes all disk I/O
pop3 server storage
pop3 client server
fstab entry: x.x.x.x:/var/spool/mail /var/spool/mail nfs bg,nfsvers=3,intr,retrans=1,udp
If Server A's nfsd go down for any reason Server B will become unresponsive to any i/o even if its i/o not ment for the nfs mount point. Putting some debug print statements in the pop3 software shows that 'it' experiences a lockup when fopen(mailbox) is called accross the nfs mount. Which is understandable but what we are not sure of is why it occurs if I want to do a `ls /home/`. I have tried useing an alarm in the pop3 software like so:
/* do stuff here */
/* continue reading mail */
What I do know is the alarm does succeed but does nothing untill the nfs mount comes back up which is run the routine for when an alarm is called.