[OpenAFS] Definitive list of AFS Limits?

Christopher Mason Mason.Christopher@mayo.edu
Thu, 21 Jul 2005 00:16:49 -0500


I'm considering OpenAFS for replacing a large Samba/RAID setup 
(10TB), and I'm trying to compile a list of the hard limits in AFS 
below, based on searching the mailing list.  I'm not sure:

1) if these limits are out of date (some of the messages are quite 

2) if there are other important limits I've missed out;

3) if there are practical limits besides these hard limits;

4) of namei/nodei differences.

Any help would be appreciated.  I'm sorry if this is considered a 
FAQ, but I search the FAW looked back to March on the archive and 
didn't see anything.


Minimum file size (overhead): FAQ says 1k file occupies 1k, but 
doesn't address overhead.

Maximum file size: 2GB???  (is this still true?)

Maximum files in a directory:  The limit depends on the length of the 
filenames; if they are all sufficiently short, the limit is around 

Maximum files in a volume:

Maximum size of a volume: 4TB

Number of servers for a read/write volume: 1 (by design)

Maximum number of servers for a read only volume:

Maximum size of a partition:
(OS limited? -- linux = 9TB?)
(Be aware that there needs to be a special
compile-time option enabled to support blockdevices larger 

Maximum cache size:
> My experience is that you want your client cache to be at least as
> large as the largest files you are using.  Performance on files that
> won't fit entirely in the cache is terrible.
... Setting cache size is a bit of a black art.

Total size of largest known AFS installation:

Can an AFS volume be grown in size?  Shrunk in size?  While online?

[ Christopher Mason  MPRC Bioinformatics  http://proteomics ]