HANFS and HACMP
Polani
I have one situation , where a two nodes cluster with cascading RG
configuration is working fine ( no HANFS configuration...)
The shared disk is on DS4800 and it contains a filesystem ( /oltlg1) ,
which has been exported from NodeB to NodeA over NFS...
Problem is that , when NodeB fails , san disk moves from NodeB to Node
A along with IP address without any problem , however application
could not be started on Node A, as by any mean ,it is still looking
for NodeA:/oltlg1;even NFS client on nodeA comes in some sort of hang
situation ( df command output hangs)...application vendor is now
saying that application still looking for NFS mounted filesystem
rather than locally available filesystem...
Is there any way to configure NFS on nodeB to export using service ip
address , rather than using nodename of NodeB? Will this approach
solve this issue?
OR Should i go straightforward for HANFS configuration rather than
simple cascading RG configuration? As per my understanding , it means
just putting NFS as part of RG? Will it be a big change in HA
configuration ( beside RG configuration changes ). I would appreciate
any document link etc...
Please advice
Regards
Uwe Auer
Hi,
what you need to configure is a so called HACMP "crossmount" (Rule: All
HACMP internal NFS mounts and exports must be controlled by HACMP)
Generally it works that way:
- Create your filesyestem to mount to /oltlg1_x (instead of /oltlg1)
- Change your RG running on NodeB (and having to perform the crossmount)
=> Change/Show All Resources and Attributes for a Custom Resource Group
Filesystems/Directories to Export (NFSv2/3) [/oltlg1_x]
Filesystems/Directories to NFS Mount [/oltlg1_x;/oltlg1]
Network For NFS Mount [<YOUR_SERVICENET>]
Don't forget to set:
Filesystems mounted before IP configured true
And create the following /usr/es/sbin/cluster/etc/exports entry:
/oltlg1_x
-sec=sys,rw,access=NodeA:NodeAp:NodeB:NodeBp,root=NodeA:NodeAp:NodeB:NodeBp
where: NodeAp = Node A's persistent label
NodeBp = Node B's persistent label
After that, synchronize cluster (a RECONFIG will occur) and crossmount
should be there and look like this:
On Node A:
=========
NodeA:/oltlg1_x 1690304512 167566488 91% 141333 1% /oltlg1
On Node B:
==========
$ df | grep oltlg1
/dev/oltlg1_lv 1690304512 167566488 91% 141333 1% /oltlg1_x
NodeA:/oltlg1_x 1690304512 167566488 91% 141333 1% /oltlg1
Hope that solves your issue.
PS: Node A needs to be a participating node in resource group containing
the /oltlg1_x filesystem for the crossmount.
Regards,
Uwe Auer
Uwe Auer
what you need to configure is a so called HACMP "crossmount" (Rule: All
HACMP internal NFS mounts and exports must be controlled by HACMP)
Generally it works that way:
- Create your filesyestem to mount to /oltlg1_x (instead of /oltlg1)
- Change your RG running on NodeB (and having to perform the crossmount)
=> Change/Show All Resources and Attributes for a Custom Resource Group
Filesystems/Directories to Export (NFSv2/3) [/oltlg1_x]
Filesystems/Directories to NFS Mount [/oltlg1_x;/oltlg1]
Network For NFS Mount [<YOUR_SERVICENET>]
Don't forget to set:
Filesystems mounted before IP configured true
And create the following /usr/es/sbin/cluster/etc/exports entry:
/oltlg1_x
-sec=sys,rw,access=NodeA:NodeAp:NodeB:NodeBp,root=NodeA:NodeAp:NodeB:NodeBp
where: NodeAp = Node A's persistent label
NodeBp = Node B's persistent label
After that, synchronize cluster (a RECONFIG will occur) and crossmount
should be there and look like this:
On Node A:
=========
NodeB:/oltlg1_x 1690304512 167566488 91% 141333 1% /oltlg1
On Node B:
==========
$ df | grep oltlg1
/dev/oltlg1_lv 1690304512 167566488 91% 141333 1% /oltlg1_x
NodeB:/oltlg1_x 1690304512 167566488 91% 141333 1% /oltlg1
Hajo Ehlers
What is anyway the reason for the NFS cross mount ? and what was you
initial goal.
Even that i am not very familiar with hacmp anmore you configuration
looks a little bit funny for me.
cheers
Hajo
In my understanding on a simple HACMP configuration :