[OpenAFS] help! volume corruption caused by lots of files

[Paul Blackburn]

Derrick J Brashear wrote:

>On Sat, 7 Dec 2002, steve rader wrote:
>
>  
>
>> > From: steve rader
>> > I have an end user who running a script under linux (2.2 or 2.4) that
>> > creates directories with perhaps as many as 100,000 files in them.
>>
>>"just don't do that"
>>
>>My thanks go out to Rubino <kb44 @ rz.uni-karlsruhe.de> for
>>pointing out the max-files-per-dir info for AFS!  [1]
>>
>>I have identified a directory with exactly 32,000 files...
>>31,998 of them are 20 characters in length.  Crazy physicists.
>>    
>>
>
>We had a usage pattern which would consistently allow 31707 (I think) 
>files and then fail. 
>
>If someone is bored, I suggest adding the stuff on the page Steve refered
>to into the Wiki. Note that the .__afsXXXX behavior isn't specific to the
>NFS translator, despite what the page claims.
>
>http://www.transarc.ibm.com/Support/afs/afsqa/general.html
>
>
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>  
>

Derrick,

I believe this is correctly stated in the AFS FAQ:

source: http://www.angelfire.com/hi/plutonic/afs-faq.html#sub2.19 


      Subject: 2.19 What are the ~/.__afsXXXX files

   They are temporary reference files used by the AFS Cache Manager.
 
   In UNIX filesystems, when you a remove a file that is kept open
   by a process, the file stays around physically while it is no longer
   referenced in any directory (which you will see as a mismatch between
   disk space usage according to df and du).
 
   Some applications rely on that feature, e.g. they create a temporary file
   and remove it immediatley while keeping the file descriptor open.
   The file then disappears from the filesystem automagically
   when the process terminates or the file descriptor gets closed otherwise.
   Such applications could get into trouble with older versions of AFS,
   where the file could really disappear while it was held open.
 
   Newer versions of AFS rename such files to .__afsXXXX, thus making sure
   that the data stays around as expected by the application. As soon as
   the file gets closed, the associated .__afsXXXX should disappear.

--
cheers
paul                                            http://acm.org/~mpb