[Linux-cluster] CS4 U4 /// HA NFS / problem

[Chris Simmons]

In 2.6 kernels, NFS clients default to mounting via TCP. Switch to UDP
using the 'udp' mount option and you'll be able to switch around your
HANFS share with only a few seconds of stalled access.

If you do keep it as the TCP, NFS clients will keep the connection in a
TIME_WAIT state for quite some time (up to 20 minutes)

Thanks,

Chris

* Alain Moulle <Alain.Moulle at bull.net> [2007-11-28 11:22:59 +0100]:

> Hi
> 
> We are currently trying to set up a HA NFS Sever (CS4u4, active/active). As
> decribed in Cookbook we use "managed nfs service" fonctionnality with ext3 FS
> type. During failover process (relocate command) we have the following problem :
> On server side everything seems to be OK (exports, IP, mount points), but on
> the client side time before ressource is back may last from 3 and 20 min
> (apparently  stalled in "rpc_execute"). Are they any specifics options to use in
> that case (NFS,ext3)?, or a well-known issue on that kernel ?
> 
> cluster.conf
>                <resources>
>                         <fs device="/dev/sdd" force_unmount="1" fstype="ext3"
> mountpoint="/tstha" name="nfsha" options=""/>
>                         <nfsexport name="nfsexport1"/>
>                         <nfsclient name="nfsclient1" target="182.20.10.68"
> options="rw,no_root_squash,fsid=7"/>
>                         <fs device="/dev/sde" force_unmount="1" fstype="ext3"
> mountpoint="/tstha1" name="nfsha1" options=""/>
>                         <nfsexport name="nfsexport2"/>
>                         <nfsclient name="nfsclient2" target="182.20.10.68"
> options="rw,no_root_squash,fsid=8"/>
>                 </resources>
>                 <service domain="NFSHA1" name="nfs_service1" autostart="1"
> checkinterval="60">
>                         <ip address="182.20.10.76" monitor_link="1"/>
>                         <fs ref="nfsha">
>                            <nfsexport name="nfsha">
>                                <nfsclient ref="nfsclient1"/>
>                            </nfsexport>
>                         </fs>
>                 </service>
>                 <service domain="NFSHA2" name="nfs_service2" autostart="1"
> checkinterval="60">
>                         <ip address="182.20.10.77" monitor_link="1"/>
>                         <fs ref="nfsha1">
>                            <nfsexport name="nfsha1">
>                                <nfsclient ref="nfsclient2"/>
>                            </nfsexport>
>                         </fs>
>                 </service>
> 
> on the client side:
> 
> [root at xena8 ~]# ps -ef |grep df
> root        85    10  0 Nov27 ?        00:00:00 [pdflush]
> root        86    10  0 Nov27 ?        00:00:00 [pdflush]
> root      3723     1  0 Nov27 ?        00:00:00 xinetd -stayalive -pidfile
> /var/run/xinetd.pid
> root     31614 31262  0 10:55 pts/4    00:00:00 df
> root     31648 28448  0 10:56 pts/2    00:00:00 grep df
> [root at xena8 ~]# cat /proc/31614/wchan
> __rpc_execute[root at xena8 ~]# umount /tstha
> umount: /tstha: device is busy
> umount: /tstha: device is busy
> 
> Thanks for help.
> Regards
> Alain Moullé
> 
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