Coda File System

Re: partitions and partition sizes

From: Patrick Walsh <>
Date: Mon, 04 Apr 2005 15:54:28 -0600
> You do not want a too big rvm on the client side, so make sure to explicitely
> indicate the max number of files expected in the cache.

	I started to calculate the cilent cache size by working backwards from
the amount of RVM data I was willing to be in memory and I found a
discrepancy.  In the FAQ it says:

"The size of RVM DATA you need can be computed roughly as follows:

      * each file needs about 500 bytes
      * each directory needs about 3,000 bytes in addition to the amount
        of space the directory entries take up (filenames + file id's).

The size of the files is irrelevant."

	But the rvmsizer program uses far different multiples.  On a file tree
with 1,902 files (130mb worth), and 118 directories, rvmsizer calculates
the RVM usage as .61mb.  But 1902 files *500 bytes + 118 dirs * 3000
bytes results in 1,305,000 bytes (or 1.24mb), more than twice as much.
rvmsizer uses 128 bytes as the file multiplier and something around 2500
bytes as the dir multiplier (depending on number of page dirs).  

	So which multiplier is more correct?	

	Also, if I'm going to allocate 150mb of client memory to rvm, how
should I work backward?  I can take 150mb and, using the 500b per file
figure determine that I can support 314,000 files -- but that ignores
directory data.  Do I have to guess how many directories are in the
cache?  Or are directories not stored in the client rvm?

Patrick Walsh
eSoft Incorporated
303.444.1600 x3350

Received on 2005-04-04 17:55:31