2012-06-08 Stalled ZFS Sync for off products on ovh3#
There were mail (for about one week) from crontab to root,
telling sto-products-sync.sh failed with cannot receive incremental stream: dataset is busy.
Looking at it on ovh3, I saw that sync was stalled since 2023-05-30 23:30
(last available snapshot, when issuing zfs list -t snap rpool/off/products)
There was also some bytes written to rpool/off/products:
# zfs get -H written rpool/off/products
rpool/off/products written 783K -
sto-products-sync.sh uses zfs recv ... -F which force update by eventually rolling back to last snapshot.
That said I issued a zfs rollback rpool/off/products@20230530-2330 to see if it would help, it didn't.
I also killed a stalled zfs recv process (launched 7h before).
But I then so that on off1, as may snapshot where already cleaned up by retention policy, the 2023-05-30 23:30 snapshot didn't exists any more… Our cleanup policy is a bit too naïve and remove everything from the previous month.
I have to change this, still in a naïve mode, to have two monthes.
It's not a big deal to keep a lot of snapshot as our products data is really incremental (we only add files).
The also a bit long because it have to come back to the 20230501-0000 snapshot,
sto-products-sync.sh should still have succeeded, but failed instead.
This is because rpool/off/clones/products is a clone based upon a snapshot from may, thus the rpool/off/products volume can't be rolledback to 20230501-0000 which is an earlier snapshot...
repairing sync#
Base clone on an older snapshot#
I did (temporarily) change the clone products to be based on 20230501-0000 snapshot.
We first have to stop staging (off.net) has it uses clones through NFS.
I verified there were no deployment action in progress.
On docker staging: cd /home/off/off-net; sudo -u off docker-compose stop
On ovh3:
zfs destroy rpool/off/clone/products
zfs clone rpool/off/products@20230501-0000 rpool/off/clones/products
Restart staging, on docker-staging: cd /home/off/off-net; sudo -u off docker-compose start
Relaunch sync manually#
To better follow what's happening I decided to manually rollback to the common snapshot: 20230501-0000
on ovh3:
zfs rollback -r rpool/off/products@20230501-0000
on off1:
zfs send -i rpool/off/products@20230501-0000 rpool/off/products@20230608-1130 | ssh ovh3.openfoodfacts.org zfs recv rpool/off/products -F
Change retention policy in scripts#
I minimally changed the retention policy part of sto-products-sync.sh to avoid removing snapshots too early (2 month ago instead of last month).
snapshot-purge.sh used on ovh3 and off2 is working differently and it's already fine, so I didn't changed it.