Coda File System

Re: Limit on directories?

From: ulrich.hahn <zrsha01_at_zdv.uni-tuebingen.de>
Date: Wed, 21 Jun 2000 10:31:20 +0200 (CEST)
On Tue, 20 Jun 2000, Jan Harkes wrote:

> On Tue, Jun 20, 2000 at 11:19:12AM +0200, ulrich.hahn wrote:
> > 
> > While testing metadata performance of coda I encountered a file system
> > full situation. The error occured after creating approx. 7000 files and 
> > directories. First I thought this might be a client problem (RVM of venus
> > assuming 16k av. file size) but this did not change with venus cache size.
> > 
> > So is there a hard coded limit for directories per volume, or what else
> > did I miss?
> 
> What is the size of the directory according to `ls'?
> 
> Greg Troxel noted at one point that we don't have indirect directory
> blocks. The directories can thus only become at most 256KB. With 7000
> entries this results in ~37 bytes per entry. 12 bytes are used by flags,
> length and fid, so the average filename size to fill a directory with
> 7000 objects would be about 25 bytes.
> 
> I don't know if that includes the \0 character at the end.
> 
> Jan
> 

The directories itself are small, 2k at most, since they are created 
recursive. As the program itself is very small I attached it.

> tb_treetest /coda/tbtree 10
creates 1023 (1013) dirs and 1013 files without problems.

> tb_treetest /coda/tbtree 11
hangs after 2045 dirs and 2035 files

Creating files is still possible, but no more directories.

I then modified the source to create 50 dirs per dir and the coda
hangs at exactly 2045 dirs again, so it doesn´t seem related to 
directory depth but simply the number of dirs.

Any clue?

Uli

: Ulrich Hahn                 email: ulrich.hahn_at_zdv.uni-tuebingen.de :
: Zentrum für Datenverarbeitung            Tel: + (49) 07071 29 70315 :
: Universität Tübingen                     FAX: + (49) 07071 29  5912 : 
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Received on 2000-06-21 04:32:15