Coda File System

General Coda Questions

From: redirecting decoy <>
Date: Wed, 9 Feb 2005 12:55:20 -0800 (PST)

I've been using coda for a few months now, and am reasonably happy with what I see.
I would like to see more in the way of stability, but I am so far happy with coda's
abilities. I have a few questions on the workings of Coda.  I figure I'll ask them here while
I sift through the various online materials I have found.

1) /vice and /vicepX are where the coda server stores it's important files correct ?  If so,
then the total amount of space available for the coda filesystem would rely on the total
amount of space available on the device /vice and /vicepX are stored.  Would there be any
drawbacks (performance wise or other) to putting the /vice and /vicepX inside of a single loopback
file  (using ext2/3, etc) of an arbitrary size?

2) To my understanding, the RVM data file needs to be at least 4% of intended total storage in
So for say, 100GB of desired storage, I would need a 4GB RVM Data file.  Is this correct ? If so,
does coda support RVM data files of this size ?

3) Large Files:  I was recentley attempting to copy a 1.5 GB file into coda.  It got to about 85%
then it
died horribly.  Not sure what went wrong, but I think it had something to do with my venus cache,
and lack of local harddrive space on the client.  
a) Can coda work with really large files 1GB and up, without major problems ?
b) If I have a client machine, with 50 megs setup for Venus cache, with a total of 200 megs
freespace on the drive, and I attempt to access a large file 1GB or more, will venus try to copy
this file locally (stick it in cache), or can it simply read from the server as needed (like
nfs/samba)? Something like maintaining an active connection to the server.

4) Given hardware availability, what is the maximum amount of storage space can coda handle?  Is
there a difference if I had 100gb of small files instead of 100 1GB files as far as RVM data, or
anything else 
is concerned?

5) If I were running httpd services, can I rely on coda to act as my shared /www directory across
my (http)servers ?  Given that there are minimal write operations, and the web services are mostly
read only.   I imagine some sort of write-caching system can be implemented, where 1 server writes
to the /www dir when necessary (to prevent conflicts), but my concern is in the connection state
of coda.  I often find that my /coda volumes become disconnected often for no obvious reason.  
Easy enough to get back online where the most drastic case would involve stopping and re-init
venus, stop venus again, then restart normally.   If this is normal behavior, how can I expect
coda to reliably serve out web-pages ?

6) Server Replication:   Using my test number, let's say I want 100GB total of coda storage space.
 If I want server replication, I assume that I would need 100GB + (total rvm data/log size) of
space available on each of my coda servers.  First of all, is this correct or does coda do some
sort of wierd parity deal like raid-5 does?    Also, I noticed that if I unplug one or more(out of
3) of my coda servers, my clients have trouble connecting, most of them eventually do reconnect to
the existing server, but not without a long (sometimes several minute) delay.   Is this expected
behavior ?  Can I change this ?

7) Volumes:  I'm guessing all the volumes/volume data are stored in /vicepX? If not, where is it?
If so,
then is there a way to distinguish what data belongs to what volume?  I only ask so I can explore
other back-up options other than what is provided with coda.
a) What is the maximum amount of Volumes I am allowed to have ?
b) How much data can I store in each volume,  is there a limit ?

ok, last questions...

8) Assuming all of my actual coda data is stored in /vicepX; 
a) If I lost my RVM Data/Log files somehow (damn gremlins), can I rebuild them without losing my
data ?
b) Can I copy the /vicepX directory to another machine, and build another completley different
coda cell and retain all the data from the original cell ?

I know, lots of questions. Sorry.  If anyone can provide any insight, it would be most

Thanks much,


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Received on 2005-02-09 15:56:46