Diskless Servers

[Charles Swiger]

On Nov 21, 2004, at 12:47 PM, Evan Sayer wrote:
> Is it a good idea to run a mail server or web server diskless?  The 
> reason I want to do this is so that all of our server's files will be 
> in one place which will make backups more convenient.  Basically I am 
> thinking of running one NFS/TFTP file server with disks, and those 
> disks will contain the partitions for a web server, a mail server, and 
> a login server which will all boot diskless.  Is this safe and ok 
> performance wise?  Thanks.

It can be done, but there are enough gotcha's lurking that you should 
be careful.  In particular, file locking [lockf(), flock(), fcntl()] 
via NFS is famously unreliable and you are strongly encouraged to use 
explicit dot-file-locking.  The portion of sendmail which handles local 
delivery (mail.local) has some discussion of this, as does IMAP/POP 
software like the U-Wash stuff.  Also be careful of stuff which uses 
the Berkeley DB.

Serving HTTP from a diskless machine is likely to work OK without too 
many problems, although watch out for the apache scoreboard (which 
wants to be unique and preferably local).

You can expect performance to be better with local drives than when 
using diskless systems.  Performance for low amounts of traffic should 
be adequate.

-- 
-Chuck