Problem with "vgchange -a r"

[SSP_1]

Hi Guys ,

I want a particular VG and its corresponding LVs/filesystems RW from one node and RO from another. Hence I have done "vgchange -a r" on another node and mounted lvols as "mount -o ro" . But now when I am making any changes on first node i.e. addidition of files , it is not getting reflected on the other node. Howz it possible, please advise.

thanks
Shripad

[Borislav Perkov]

Hi Shripad,

Please be precise how the VG is activated on first node and is this member of cluster?

Regards,
Borislav

[SSP_1]

Hi Boris ,

The VG is not part of cluster. Following example best illustrates the problem.

Node A = Primary = Read-Write Mode

Node B = Secondary= Read-Write MOde.

Both are running with hpux 11.11 and are npar of superdomes.

[Borislav Perkov]

I think on the first if should be in share mode. Or maybe the solution of this is to make a nfs mount from the second to first.

Regards

[Simon Hargrave]

You cannot have the filesystem mounted on one server r/w and on another r/o and expect the changes to be visible on the second server at the same time. Each server maintains its own buffer cache as a "window" on the filesystem. With this it views unflushed blocks, as well as keeps a record of dirty blocks etc. When the r/w server writes, the r/o server has no way of knowing to read the newly dirtied blocks.

If you want this functionality, mount the filsestem as r/o via NFS on the "other" server.

I believe advfs on Tru64 supports this configuration, and in the future this may be ported into the HPUX tree (given the amalgomation of tru64 features in hpux).

For now though, nfs is your best option.

[Sunil Sharma_1]

LVM doesn't support this. You have to use NFS to get this done.

Sunil