Hi,
I'm designing a storage layout for a virtualization framework and want to
sanity-check the approach against a real thin-pool user before I commit to it.
Setup:
- One VG, one thin pool
- A small number of read-only "base image" thin LVs inside the pool
(set with lvchange -pr)
- Per-session thin snapshots of those base images ("writeback" disks) —
each session writes only into its own snapshot, and gets lvremove'd
when the session ends
Questions:
1. Is there any way to mark a thin LV as "low value / freely disposable"
so that pool-level health/monitoring treats a failure on that LV
differently from a failure on the read-only base LV? As far as I can
tell there's no such attribute and tags are the only practical way to
distinguish them for my own tooling — is that right, or is there a
built-in mechanism I'm missing?
2. If a single snapshot LV is reported as partial/failed by dmeventd,
is it always safe to lvremove -f just that LV without affecting the
pool's metadata health, as long as the pool itself isn't reporting
failed? Or are there edge cases where a single bad snapshot can
still corrupt shared pool metadata?
Happy to share more detail on the workload if useful. Thanks for any
pointers — I read through the pvcreate/lvmthin man pages but couldn't
find a definitive answer on point 1 and 2 specifically.
Thanks.
