[linux-lvm] Unexptected filesytem unmount with thin provision and autoextend disabled - lvmetad crashed?
g.danti at assyoma.it
Sun May 15 10:33:08 UTC 2016
I had an unexptected filesystem unmount on a machine were I am using
It is a CentOS 7.2 box (kernel 3.10.0-327.3.1.el7,
lvm2-2.02.130-5.el7_2.1), with the current volumes situation:
# lvs -a
LV VG Attr LSize Pool Origin
Data% Meta% Move Log Cpy%Sync Convert
000-ThinPool vg_storage twi-aotz-- 10.85t
[000-ThinPool_tdata] vg_storage Twi-ao---- 10.85t
[000-ThinPool_tmeta] vg_storage ewi-ao---- 88.00m
Storage vg_storage Vwi-aotz-- 10.80t 000-ThinPool
[lvol0_pmspare] vg_storage ewi------- 88.00m
root vg_system -wi-ao---- 55.70g
swap vg_system -wi-ao---- 7.81g
As you can see, thin pool/volume is at about 75%.
Today I found the Storage volume unmounted, with the following entries
May 15 09:02:53 storage lvm: Request to lookup VG vg_storage in
lvmetad gave response Connection reset by peer.
May 15 09:02:53 storage lvm: Volume group "vg_storage" not found
May 15 09:02:53 storage lvm: Failed to extend thin
May 15 09:02:53 storage lvm: Unmounting thin volume
vg_storage-000--ThinPool-tpool from /opt/storage.
The lines above repeated each 10 seconds.
What puzzle me is that both thin_pool_autoextend_threshold and
snap_pool_autoextend_threshold are disabled in the lvm.conf file
(thin_pool_autoextend_threshold = 100 and snap_pool_autoextend_threshold
= 100). Moreover, no custom profile/policy is attached to the thin
To me, it seems that the lvmetad crashed/had some problems and the
system, being "blind" about the thin volume utilization, put it offline.
But I can not understand the "Failed to extend thin
vg_storage-000--ThinPool-tpool", and I had *no* autoextend in place.
I rebooted the system and the Storage volume is now mounted without
problems. I also tried to write about 16 GB of raw data to it, and I
have no problem. However, I can not understand why it was put offline in
the first place. As a last piece of information, I noted that kernel &
lvm was auto-updated two days ago. Maybe it is related?
Can you give me some hint of what happened, and how to avoid it in the
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email: g.danti at assyoma.it - info at assyoma.it
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