Coda File System

coda + reiserfs + qmail in high availability production environment

From: Cain Ransbottyn <>
Date: Thu, 19 Jul 2001 01:43:58 +0200
Hi there,

we need your advice ;-)

We @ will bring some new production servers online next week : 2
webservers both using reiserfs and acting as 'clients', 2 mailservers with
the same setup and one database server also with the same layout. They are
all 'clients' of a dedicated fileserver (also running reiserfs) with the
coda server running on it. We are using RedHat as a default linux distrib.
The 'clients' are 'normal' stripped and highly secured linux boxes... they
have nothing installed, no compilers,... they mount their binaries through
the coda filesystem (i.e. /packages/apache will be coda-mounted on the
webserver, /packages/qmail will be mounted on the fileserver.) If one of the
servers fails, another server can do failover by bringing up an ip:alias of
the 'dead' client and coda-mount the /packages/*binary*.

Also all the data will be located on the fileserver. /web on the webserver
will be a mount to /local/web on the fileserver through coda. We don't want
to make this fileserver the only point of failure so we do a rsynch every
hour from /web on the client to /local/web on the client (each client has
extra disk space). So if our coda file server fails we always have a
/local/web with a 'backup'.

If the fileserver fails (network or hardware probs), will it be easily to
automagically umount the /web on the 'previous coda fileserver' and make a
symlink from /local/web on the client to /web on the client. This is
scripted and should all be done in a couple of seconds? We didn't succeed to
do this with 'regular NFS'. Will this umounting work with coda ? Will we be
able to umount the /web in let's say 2 seconds after the hardware crash ? (I
assume we first have to auto-kill the applications using the current mount).
Is this a good way of thinking or are we driving ourself nuts ?

I've read quite a lot of threads about reiserfs and I noticed that there are
still some problems... I assume I make my /usr/coda/venus.cache/ on my
clients (the mailserver, webserver,...) on 'normal' ext2 ?

Can I leave my fileserver on reiserfs completely ? Even the / ? What about
my clients ? Is the above 'venus.cache-ext2-trick' going to work ? Do you
prefer reiserfs, xfs or ext3 ?

What about qmail ? Will coda or reiserfs have problems with qmail ? What
should we do about it to get this fixed ?
I saw quite a lot of patches but which one will provide us the best
performance and can garantuee us no data loss ?

All your thoughts on this matter are welcome... I would love to start a
discussion on this ;-)

Received on 2001-07-18 19:37:16