Properties Of Snapshots
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- The first property of a snapshot, is the amount of disk space it was given.
If we run out of disk space (too much of the original volume changed),
the kernel will drop the snapshot.
- The size of a snapshot may be increased while it is mounted. No need for
file-system resizing tricks here.
- A snapshot may be read-only or read-write. If it is read-write, then
the snapshot's disk space is also used for writing on top of the snapshot.
- When creating a snapshot, we may define the chunk size (i.e. how much
data to COW when there is a change in the original volume). A larger
chunk means better throughput, but possibly higher latency, and more
waste of disk space.
- We may stack snapshots together (everything in LVM2 is stackable). The
performance of reads might degrade.