[OpenAFS] Definitive list of AFS Limits?
Thu, 21 Jul 2005 10:00:03 +0200
On Jul 21, 2005, at 7:16 AM, Christopher Mason wrote:
> Minimum file size (overhead): FAQ says 1k file occupies 1k, but
> doesn't address overhead.
That's minimal and heavily depends on you directory structure. But
not noticeable at all.
I said depends on your structure since you have mount points, ACLs
etc. to handle on the fileserver. I never heard anybody complain
about that in the past. (whatever that now means to you ...)
> Maximum file size: 2GB??? (is this still true?)
The release fileservers do have this limit.
If you're compiling the fileservers yourselves you can switch the
large file support on, but that's experimantal AFAIK.
> Maximum files in a directory: The limit depends on the length of
> the filenames; if they are all sufficiently short, the limit is
> around 64K.
This one's correct. ;-)
> Maximum files in a volume:
> Maximum size of a volume: 4TB
This would be approximately accurate as well (AFAIK it's not exactly
4TB but somewhere in that area, never cared about the accurate
number, though :-) )
> 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?)
OS limited since the partition is on a file system on your fileserver.
> (Be aware that there needs to be a special
> compile-time option enabled to support blockdevices larger
Can't comment on that since I never had such devices :-)
> 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.
Yes, cache size and parameters for the clients is more like a
> Total size of largest known AFS installation:
Now here i think you won't get any "proud and cocky" answer since the
AFS guys are not running around with the number of TBs around their
neck for every body to know. :-)
BTW, if you're using AFS it's the same way of handling data whether
you handle 2.1GB or 200TB.
> Can an AFS volume be grown in size? Shrunk in size? While online?
They do that all by themselves since a volume is not a "physical
unit" but an administrative one.