Coda File System

RVM Log and Metadata Sizes

From: Stephen J. Turnbull <>
Date: Thu, 31 Jan 2008 05:52:36 +0900
Things seem quiet here lately, so I'll hazard a couple guesses to get
you started.  But you really should search the archives for this, I'm
sure it has been discussed a fair amount. writes:

 > Is there an official limit on RVM log and metadata file sizes? I set my 
 > log size to 2GB in order to be able to handle files up to 2GB. Ideally, I 
 > wanted to be able to handle a FS up to 0.5TB, so I wanted to make a 
 > metadata file of about 16GB. The biggest I've managed to get to work is 
 > 4GB, otherwise things fail with an error. Does this sound about right?

ISTR that the protocol for communicating among Coda hosts was
32-bit-size-oriented, but recently may have been updated to 64-bit
sizes at the cost of backward compatibility, so it might be on a
branch.  Anyway, this would impose a hard limit of 4GB (2GB if signed)
on file sizes.  Note that this is a wire protocol issue, so a global
substitution of off64_t for int won't help, but rather just introduce

 > On a related note, are any of these limits (file/log/metadata) 
 > architecture dependant? If so are there any issues with having an 
 > x86-64 and an IA32 node in the same replicated cluster?

I don't think they're CPU-dependent, rather they depend on (a) large
file support in the OS, and (b) a change in the Coda wire protocol.
Received on 2008-01-30 16:06:04