[OpenAFS] Debugging AFS sluggishness on MacOS 10.5.7?

Felix Frank Felix.Frank@Desy.de
Tue, 30 Jun 2009 07:37:57 +0200

> Another tidbit that is either hopelessly banal because I don't 
> understand how AFS works, or really important: WRITING to the same AFS 
> directory works fine. I copy the file from the directory to my local 
> disk and it takes 4 minutes; I delete the file from the remote disk and 
> write it there from my local disk and it takes 30 seconds.

Just a side remark: If the file is smaller than your cache, then this is 
probably the cache manager writing to the cache, which is supposed to be 
fast. I'd expect a rather sharp corner in the write performance curve as 
soon as your amount of data surpasses disk cache size.

On Linux, I have also found the memcache to make more balanced and 
efficient overall use of your bandwidth when transferring bulk data.
I haven't thoroughly investigated random access to small files, but the 
expectation is that a large-ish disk cache is at an advantage for that.

  - Felix