Nextcloud Backup without Data

[msbt]

# cd /var/storagebox/test
# touch foo
# ln foo bar
# ln foo baz
# ls -l foo bar baz
-rw-rw---- 3 yellowtent yellowtent 0 May 11 20:44 bar
-rw-rw---- 3 yellowtent yellowtent 0 May 11 20:44 baz
-rw-rw---- 3 yellowtent yellowtent 0 May 11 20:44 foo

rather disappointing, seems to work

[girish]

@msbt If possible, please trigger a backup as well with hardlinks. I would like to know why it fails. Maybe there is some limit somewhere we are hitting in CIFS.

[msbt]

ok, switched to rsync + hardlinks, testing

[nebulon]

Just to give a bit more information here. I can confirm that sometimes creating hardlinks within a cifs mount on a hetzner storage box fails like:

root@my ~ # cp -al /backups/snapshot/app_caafd030-50c4-413d-82b8-733e28d9da01/data/public/ /backups/foo
cp: cannot create hard link '/backups/foo/public/css/fonts/element-icons.ttf' to '/backups/snapshot/app_caafd030-50c4-413d-82b8-733e28d9da01/data/public/css/fonts/element-icons.ttf': No such file or directory

However as soon as I touch or read/write that failing file, it starts working just fine.

If someone else here sees the same issue, maybe you can try to also see if touching a file which is failing fixes the hardlink creating. Given that this seems quite the sporadic issue, it would help to gather more information here to see if this indeed is consistent.

[iqweb]

I'll switch back to rsync with hardlinks & try touching the error files too

[girish]

@iqweb We are monitoring @nebulon 's backups in the meantime, so we can find a workaround. Maybe as simple as a retry or maybe using rsync instead or creating hardlinks manually in node might do the trick.

[msbt]

I've been using hardlinks for a few days now and encountered no problems so far. Would the backup job notify me if some links couldn't be generated? Not sure what happened the last time I tried that.

[nebulon]

Yes you would receive a notification and email if a backup job failed

[iqweb]

Seems to be working for me now too!

[jdaviescoates]

@iqweb said in Nextcloud Backup without Data:

jdaviescoates - Do you mean the borgbackup to Hetzner storagebox - or the Synology pull?

Both! Thanks

[nebulon]

Just a heads up, I have seen some bad behavior with cifs mount and hard-links on my personal Cloudron, which made some backups corrupt.

So please everyone who is using this for now with relevant data, do not use hardlinks.

[girish]

We have now setup a separate hetzner box to sync large amount of data to debug this issue.

[jdaviescoates]

@nebulon said in Nextcloud Backup without Data:

So please everyone who is using this for now with relevant data, do not use hardlinks.

I'm not sure if this applies to me or not. I backup to a Hetzner Cloud Volume (not storage box). Currently I have hardlinks enabled. Should I turn them off?

What should I look for in the logs to see if this is effecting me?

Thanks!

[nebulon]

It highly depends on how a "disk" is mounted onto the server. The hardlinks issue is only there for cifs mounts and since cifs/samba support hardlinks since a very long time, this seems to be related in particular to the hetzner storage boxes at the moment.

[jdaviescoates]

@nebulon OK thanks, so I don't think this applies to me.

This is how Hetzner Cloud Volumes are mounted:

[nebulon]

correct in your case this should not be any issue as this is mounted like a regular ext4 which supports hardlinks just fine.