Re: reiserfs3, rsync and hardlinks

[Vladimir Saveliev <vs@namesys.com>]

Hello

On Mon, 2005-02-07 at 23:50, Pierre Etchemaite wrote:
> Le lun 07 fév 2005 13:22:51 CET, Vladimir Saveliev <vs@namesys.com> a écrit
> :
> 
> > Hello
> 
> 	Hi,
> 
> > yes, reiserfs reuses inode number of removed files for newly created
> > files. However, ext2 also does that. Have  you ever noticed this problem
> > on other filesystems?
> 
> No, but I'm only using rsync -H for a few weeks. The problem may also exist
> with tar, but unnoticed (unless tar detects hardlinks in a different way,
> or does more checks, like checking the consistency with references counters,
> whatever, to avoid it). rsync handles hardlinks in a final pass, so as soon
> as the verbosity level is raised, problems are easy to detect.
> 
> I have only one server left that uses ext2. It's also saved with rsync, no
> problem seen so far (a few weeks only, as I said).
> But the filesystem used isn't the only difference. Usage pattern probably
> matters a lot. On the system where it happens, hardlinked files are often
> Maildir files (unsurprizingly) and mrtg log files (which are rotated every 5
> minutes). inodes are probably freed by mrtg, and one reused for a new email.
> 
> > You can try to make reiserfs to not free inode numbers of removed files
> > with the attached patch and check whether it helps. It decreases number
> > of files which can be created on a filesystem to ~2^^32.
> > I am not sure if it is enough for low traffic IMPA server.
> 
> Ok, I can probably try this hack to verify the hypothesis. 

Yes, please do that.

> But what are the
> drawbacks, on the long term ? Lost disk space ? What happens if all inode
> numbers get allocated ? 

open(O_CREAT), mkdir, etc will refuse to create files. ENOMEM will be
returned.


> mkreiserfs ?
> 
> Best regards,
> Pierre.
>