no idea or no solution?

rs6000er wrote:
> hi all
>
> I just recently have been asked if the jfs/jfs2 filesystems could be
> online protected. for lvs/raw devices, most time we could mirror the
> lv/raw device to another physical/logical disk to make a online
> synchronizing copy so that the lv/raw devices won't lost any data or
> accession when one copy is not availiable or seating the edge of crash.
>
> accroding jfs/jfs2 filesystems, JFS online backups and JFS2 snapshots
> seem to be able to protect the data. but I am wondering if either JFS
> online backups or JFS2 snapshots can handle the filesystem crash and
> let user keep access the data in crashing filesystem which has been
> protected by online backup or snapshots.
>
>
> any idea would be appreciated,
>
> thanks in advance
>
> Frank

rs6000er schrieb:

> no idea or no solution?

An crashing FS is a crashing FS. You can not move to different JFS/JFS2
FS ( sync or asyncronus backup ) because inodes are not the same,
application I/O has not finished and so on. So in case of a FS crash
you must restart your application and using the backup FS.

Another approach would be to use GPFS with replication and in case the
local access to the disk is lost it will switch the the backup node
transparently. BUT in case the GPFS crashed it will not help either.

Also you might take a look at NFS 4 for failover scenarios, meaning to
access the data via NFS 4 ( even locally ) and in case of a failure
switch to a backup NFSv4 server.

But to be honest i think you should explain your initial problem and
not asking for a solution.

hth
Hajo