Coda File System

Re: Want a 120GB coda server

From: Phil Nelson <phil_at_cs.wwu.edu>
Date: Fri, 7 Dec 2001 10:49:03 -0800 (PST)
Hello David,

  You said:

>After reading the mailinglist, I understand that the RVM meta-data 
>should be on a file, so that i mmaps, but with only 128MB on the system, 
>this will be too short for a 120GB*0,05=6GB RVM meta-data file???

The problem is not is 128MB big enough for a 6GB RVM file, you can't
mmap a 6GB RVM file on 32bit architectures.  Most of the OSes that
coda supports, the biggest RVM segement you can get is less than 2GB.

The largest RVM size for Coda servers that the standard setup scripts
supports is 1GB.

I have used the 1GB RVM to serve 33 Gig of disk.  The setup I used
was 2 coda servers on the same machine.  (Using the 5% rule you mentioned
above, you could serve up to 40G of disk.)  Each coda server needs
a unique hostname at this time, so I have an IP alias for the second
server.

So to serve 120GB, you could use 6 20GB coda servers.  You would need
6 host names.  Also, you wouldn't want to replicate volumes on the same
machine.

As for your real question of would 128M be enough real memory to support
this, I would think it would be just fine.  You won't have all 6G of
RVM in real memory at the same time.

--Phil

p.s.: If you wanted to play yourself with setups, you might be able to
set up a 1.5G RVM segment so a server could then serve 30G of space.
Then it would require only 4 servers for the 120G of space.

-- 
Phil Nelson                       NetBSD: http://www.netbsd.org
e-mail: phil@cs.wwu.edu           Coda: http://www.coda.cs.cmu.edu
http://cs.wwu.edu/faculty/nelson 
Received on 2001-12-07 13:50:34