Question about LVM snapshots - Read-only vs Copy-On-Write
by Vanyel from LinuxQuestions.org on (#54MSQ)
I'm new to LVM snapshotting. I need an experienced LVM user to verify if I've got this right:
What I want is to use LVM to take a static snapshot of my LVM filesystem so I can then mount that and use rsync to back up the unchanging, frozen copy while my original is instantly returned to service and new changes are made.
So what I want is a READ-ONLY snapshot, vs a Copy-On-Write snapshot, correct?
My first attempt using default LVM options failed - additions (though not deletions) made to the source were also made on the snapshot. I believe that's COW.
When I made a R/O snapshot that seemed to work - changes on the source were not reflected on the snapshot.
Am I missing anything about R/O snapshots or will this work?
ALSO - is there any way to create a COW snapshot and then change it into R/O on the fly, so I can routinely have a live copy online to revert to, but then make it static during nightly backup?
I'm using CentOS 7 btw.
What I want is to use LVM to take a static snapshot of my LVM filesystem so I can then mount that and use rsync to back up the unchanging, frozen copy while my original is instantly returned to service and new changes are made.
So what I want is a READ-ONLY snapshot, vs a Copy-On-Write snapshot, correct?
My first attempt using default LVM options failed - additions (though not deletions) made to the source were also made on the snapshot. I believe that's COW.
When I made a R/O snapshot that seemed to work - changes on the source were not reflected on the snapshot.
Am I missing anything about R/O snapshots or will this work?
ALSO - is there any way to create a COW snapshot and then change it into R/O on the fly, so I can routinely have a live copy online to revert to, but then make it static during nightly backup?
I'm using CentOS 7 btw.