Originally Posted by parikpol
Is there any way we can mount a file system on top of a mirrored/replicated volume? I am ok with having a read only filesystem on top of the mirrored volume, as long as the filesystem reacts to changes to the data in volume on top of which it is mounted.
If the mirrored/replicated volume is on a separate system and the volume
is receiving updates from the volume on another system, then you do not
want to mount a file system on the mirrored/replicated volume.
The reason is that the replication is done on the block level, the file
system on the top has no knowledge of what the replicated volume will
contains after mounting as it continues to be replicated and updated
by another volume. The following FAQ page about DRBD is an example,
"Can I mount the secondary at least readonly?"
This problems exists on every block level replication products like
disk replication(DRBD), storage replication, volume replication
implemented on either software or hardware.
You can mount the mirrored/replicated volume safely only after the
replication is stopped due to remote system's failure or being shutdown.
The system may have to run the fsck first to make sure that the
replicated volume is in consistent state.