[linux-lvm] auto umount at thin meta 80%
list at xenhideout.nl
Sun May 22 17:07:26 UTC 2016
I am not sure if, due to my recent posts ;-) I would still be allowed to
write here. But, perhaps it is important regardless.
I have an embedded LVM. The outer volume is a cached LVM, that is to
say, two volumes are cached from a different PV. One of the cached
volumes contains LUKS.
The LUKS, when opened, contains another PV, VG, and a thin pool.
The thin pool contains about 4-5 partitions and is overprovisioned. Only
one volume is in use now.
This thin volume called "Store" is almost the full size of the thin
pool, but not quite:
store vault Vwi-aotz-- 400.00g thin 40.37
It currently stores a backup, I was writing some backup scripts.
The volume apparently got umounted when the meta of the thinpool reached
10:47:21 lvm: WARNING: Thin pool vault-thin-tpool metadata is now
10:47:21 lvm: Request to lookup VG vault in lvmetad gave response
Connection reset by peer.
10:47:21 lvm: Volume group "vault" not found
10:47:21 lvm: Failed to extend thin pool vault-thin-tpool.
Not sure why the discard is unsupported, but I guess I opened the LUKS
container without it:
[ 1033.399934] device-mapper: thin: Data device (dm-13) discard
unsupported: Disabling discard passdown.
[ 1171.656307] device-mapper: thin: 252:14 [ 14 == tpool ]: reached low
water mark for data device: sending event.
Suddenly my mounted filesystem was gone:
# mount | grep /mnt
And VIM reports:
E211: File "update.sh" no longer available
I still have handles open, so the thing must have been lazily umounted.
The meta was created (automatically) with only 112M:
thin vault twi-aotz-- 437.05g
[thin_tdata] vault Twi-ao---- 437.05g
[thin_tmeta] vault ewi-ao---- 112.00m
112M seems low for meta if a proportion of 1:1000 is usually required?
There are hardly any files on the volume(s), just a few archives
totaling currently 160G.
This is LVM version 2.02.133(2) (2015-10-30) / 1.02.110 (2015-10-30)
The instant umount at 80% seems rather premature.
I will recreate the volume and try to create a larger meta volume for
I'm not sure if 0.1% of the data size will be enough though, given this
but wel'll see.
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