Lost files due server crash, lost files removed on clients too?


#1

Well, nextcloud server running on a remote location experienced major disk failures (with RAID) and recovered somehow, but many files disappeared in the system and nextcloud data/[user]/* as well (this wasn’t obvious until later).

And nextcloud client on my laptop started to remove the files on its disk and before I could stop it, the files were gone. So, the file corruptions or disappearance of the nextcloud server spread to my laptop - is this normal behavior of nextcloud?


#2

unfortunatly, it is a normal synch app behaviors…

Remember, nextcloud is not a backup solution unless specific cron jobs and manual scripting.

Second thing, a RAID failling and recovering only a part of the files, this is weird.

I am interrested in the raid info, could you be more specific.


#3

unfortunatly, it is a normal synch app behaviors…

A server instance, with the authority to request deletes from clients, should take measures to conclude in which manner files disappeared, e.g. requested from clients or delete on the server itself, or disappeared without inotify:unlink - the redundancy inherent is really thrown out of the window with the server requesting clients to delete their files as well without any second guessing.

Remember, nextcloud is not a backup solution unless specific cron jobs and manual scripting.

I partially relied on the server to conclude what I just mentioned, and provide some backup functionality, but I was mistaken.

Second thing, a RAIS failling and recovering only a part of the files, this is weird. I am interrested in the raid info, could you be more specific.

Two physical disks with mdadm in RAID1, one disk failed entirely, the 2nd disk having errors as well (has gone unnoticed until too late), I was also surprised on the ordered manner I lost data.


#4

This is how Nextcloud is designed, yes. There is currently a security mechanism which comes into play, if the full primary storage is not available, at some point you got deletes in this case as well. There is also a mechanism in the client if too much stuff is deleted server side. I guess additional ideas and coding of mechanisms is welcome here, as well as with the folks from ownCloud.


#5

I concur.
This is why i use the synch stuff for non-important files. Or copy/move important files on a non-synch folder.
Some apps are available to “recover” or have an “history” of files added/deleted. I personnaly dont use them.
I use daily snapshots for files history ( server wide; including os )
If you come out with a good idea or an app to fillfull your requieremnets, just throw the idea to the devell.

Life is like a box of chocolate. This is certainly true with raid.
I manage two server:

  • my familly server: debian + mdamd + lvm2 on a raid6 array ( 5*10TB ). I have lvm2-monitor enable, and a weekly check of the array. I am running this configuration for other 3 years. All five disk came from amazon, all five brand new and the same model. I just ordered them from 5 differents sellers. Since the start up of this server, i had one disque crash during the 2 first months and had to RMA it. The rebuild process is (so far) flawless and is taking around 340 minutes.
  • my company owned a storinator s45 as primary server, and a s45lite as backup. both are set up with the specific CentOS with GlusterFS and ZFS on Linux running on top with a raid60 setup:
    raid30
    Our raid 60 is set with two array type raid6 ((15*10TB ) * 2 ). each of them having 2 spares disk. raid6-1 and raid6-2 are reunited on a raid0 array. The build was made directly by s45drives.
    We experience an array crash due to a faulty controller. Hardware was fixed and nothing was lost…
    We still have 15 slots free for futur upgrades ( one schedule in september, as we plan to expand the size of the actual arrays.

To conclude, for me nextcloud is a simple light tools who provide some services with a low level of security redudancy.
Some of is flaw can be managed through the OS and some trick/scripts.
It is more oriented familly than large corporation… even if they claim the german governement is using nextcloud server.