[CentOS] boot-time NFS mount failures

Fri Apr 20 14:27:53 UTC 2012
Tilman Schmidt <t.schmidt at phoenixsoftware.de>

Am 19.04.2012 19:30, schrieb Veli-Pekka Kestilä:
> On 19.4.2012 20:12, Tilman Schmidt wrote:
>> backup:/home/backup/Oracle      /backup_nfs     nfs
>> The last time this happened, I found a message on the console:
>> mount: can't get address for backup
>> So it seems that the failure was caused by the nameserver not being
>> available yet. Unfortunately that message isn't saved to any logfile,
>> so I cannot say if it was the same the previous times.
> You could set in fstab ipaddress instead of the server name, so there is 
> no need for name lookup or you can put the ip and name in /etc/hosts

So you say it's only the name lookup failure that's causing
startup to proceed without the NFS mount? All other failures
like host unreachable or NFS port not open would cause the
system to wait and retry?

> Where the nameserver is? On the backup server or on the oracle (or on 
> completely separate machine?)

Separate machine.

> - If on separate machine you could write your own init script which 
> tests that the name resolution works and runs the oracle startup after that.

It would have to go before the netfs service I think. That's
the one which does the NFS mount. The oracle startup script
runs after netfs, so all would be fine if netfs wouldn't exit
without having mounted the NFS shares.

> I would put the ip in hosts if the backup server has fixed ip-address. 
> If not then making special init-script could be the trick.

My concern are possible other failure modes besides the
name lookup.
What happens if the IP address is available (hardcoded or
via name resolution) but the NFS server is offline?
What if the NFS server machine is online (say, pingable) but
the NFS service doesn't listen (yet)?
I have to make sure that in all these cases the Oracle
processes do not get started until the NFS mount is


Tilman Schmidt
Phoenix Software GmbH
Bonn, Germany