NFS Services Administrator's Guide (762805-001, March 2014)

/opt/nfstest from hpnfsweb:/home/tester
Flags:
vers=3,proto=udp,sec=sys,hard,intr,link,symlink,acl,devs,
rsize=32768,wsize=32768,retrans=5,timeo=11
Attr cache:
acregmin=3,acregmax=60,acdirmin=30,acdirmax=60
Lookups: srtt=33 (82ms), dev=33 (165ms), cur=20 (400ms)
The directory that you have mounted must be present in this list.
For a list of mount options, see mount_nfs(1M).
Enabling Client-Side failover
Using client-side failover, an NFS client can switch to another server if the server supporting a
replicated filesystem becomes unavailable.
The failover is usually transparent to the user. Failover can occur at any time without disrupting the
processes running on the client. Failover is only supported on read-only filesystems.
To mount a directory that has been replicated on multiple servers, enter the following command:
mount -o ro svr:dir_name,srv:dir_name dir_name
If the first NFS server is down, the client accesses the second NFS server.
For example, to mount the Casey directory to replicated servers, enter the following command:
mount -o ro onc21:/home/Casey, onc23:/home/Casey /Clay
If the NFS server onc21 is down, the client accesses NFS server onc23.
To verify if the failover is in effect, enter the following command:
nfsstat -m
An output similar to the following output is displayed:
/Clay from onc21:/home/Casey,onc23:/home/Casey
Flags:
vers=3,proto=tcp,sec=sys,hard,intr,llock,link,symlink,acl,
devs,rsize=32768,wsize=32768,retrans=5,timeo=600
Attr cache: acregmin=3,acregmax=60,acdirmin=30,acdirmax=60
Failover: noresponse=0,failover=0,remap=0,currserver=onc23
The Failover line in the above output indicates that the failover is working.
Examples of NFS Mounts
• Mounting a directory as read-only with no set userid privileges
mount -r -o nosuid broccoli:/usr/share/man /usr/share/man
In this example, the NFS clients mount the /usr/share/man directory from the NFS server
broccoli. The local mount-point is also /usr/share/man. The directory is mounted as
read-only.
Figure 4 illustrates this example.
38 Configuring and administering NFS services