Share a File-system between two HPUX servers (NFS/Samba not an option)

[FTSE SysAdmin]

Hi,

Would someone know a way to share two filesystems between two or more HP-UX servers, without the use of NFS/Samba?

CASE:
I used to provide this "HP unsupported" feature when I had 3 servers connected to a VA7400 where one of them shared one FS (read-only) to the other two. The caveats are, any updates to that FS, the other servers would not see the changes (until the FS is re-mounted), beside loging LVM errors on that read only FS. This worked perfectly dispide those LVM minor errors.

Now I upgraded the diskarray from VA7400 to EVA5000 (secure path).

I know, that I can provide this feature (HP unsupported) even with EVA and securepath. However I'm looking for a proper solution instead of this "hacking".

I know that Veritas for SUN can do this, however I'm not aware of such thing for HP-UX...

So, would someone know a solution for this case?

Many thanks

[Pete Randall]

I believe this is possible in the Service Guard environment. Take a look at the vgchange man page, in particular at the -s option and the section on "High Availability Cluster Overview".

Without MCSG, however, you're limited to "hacking".


Pete

[Duncan Edmonstone]

HP are just announcing an integrtaion between Serviceguard and the Veritas CLuster File System (CFS) that should fit your requirement. It's not due for general release until December, but there already a few morsels of info on the HP website - have a look here:

http://h71028.www7.hp.com/ERC/downloads/4AA0-1401ENW.pdf

HTH

Duncan

[Arunvijai_4]

You can do it with VCS4.0 what i have done between Solaris 9&10 nodes . But, I am not sure (i haven't done that yet) in HP-UX world. It should be possible though...

-Arun

[FTSE SysAdmin]

I'm not familiar with ServiceGuard (yet), that's why the following "noob" doubt :)

Would ServiceGuard handle the mount through the network or directly through disk devices?

I suppose that since its a cluster software, then it will handle the mounts through disk device level (and not through network) and the reference to the network is just for some heartbeat control.

[Duncan Edmonstone]

Your suppositions are correct. The mounts will not be over the network - only control and heartbeat traffic is over the nework.

Of course if you have an application accessing these files on multiple nodes, you still need to provide some form of sitributed locking mechanism yourself.

HTH

Duncan

[Bill Hassell]

Service Guard is a product to allow multiple machines to be used in a failover mode. IF the only task is to 'share' a filesyetem, then it would be quite expensive (per processor licensing). The reason you see errors is that VxFS is unaware of any other use of the filesystem. Although it would seem reasonable to 'share' a filesystem, there must be extensive code changes to prevent problems in the directory structures. Even a read-only filesystem still allows a user on another computer to cd into a directory, simple but very complex in managing VxFS. Scenarios like: primary decides to umount the filesystem - secondary is now confused because it appears to be mountted and unmounted at the same time...and so on.

SO this is truly a hack and should never be put into production. The only proper solution requires a shareable filesystem and for basic HP-UX, that is currently limited to NFS.