Hi Gregory,

Thanks for the help! I've been looping over all trashcan files and the amount 
of strays is lowering. This is going to take quite some time as it are a lot of 
files but so far so good. If I should encounter any further problems regarding 
this topic, I'll give this thread a heads up.

Kind regards,

Davie De Smet
Director Technical Operations and Customer Services, Nomadesk
+32 9 240 10 31 (Office)

-----Original Message-----
From: Gregory Farnum [mailto:gfar...@redhat.com] 
Sent: Wednesday, October 12, 2016 2:11 AM
To: Davie De Smet <davie.des...@nomadesk.com>
Cc: Mykola Dvornik <mykola.dvor...@gmail.com>; John Spray <jsp...@redhat.com>; 
ceph-users <ceph-us...@ceph.com>
Subject: Re: [ceph-users] CephFS: No space left on device

On Tue, Oct 11, 2016 at 12:20 AM, Davie De Smet <davie.des...@nomadesk.com> 
> Hi,
> We do use hardlinks a lot. The application using the cluster has a build in 
> 'trashcan' functionality based on hardlinks. Obviously, all removed files and 
> hardlinks are not visible anymore on the CephFS mount itself. Can I manually 
> remove the strays on the OSD's themselves?

No, definitely not. At least part of the problem is:
*) Ceph stores file metadata organized by its *path* location, not in a 
separate on-disk inode data structure like local FSes do.
*) When you hard link a file in CephFS, its "primary" location increments the 
link counter and its "remote" location just records the inode number (and it 
has to look up metadata later on-demand).
*) When you unlink the primary link, the inode data gets moved into the stray 
directory until one of the remote links comes calling.

>Or do you mean that I'm required to do a small touch/write on all files that 
>have not yet been deleted (this would be painfull as the cluster is 200TB+)?

Luckily, it doesn't take quite that much work. It looks like just doing a 
getattr on all the remote links in your system should do it.
If it's just your trash can, "ls -l" on that directory will probably pull them 
in. Or you could delete the whole trashcan folder (set of
folders?) and they'll go away as well.
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