[svlug] Re: system with read-only root filesystem

Richard Sharpe rsharpe at ns.aus.com
Wed Jul 3 10:57:58 PDT 2002


On Wed, 3 Jul 2002, Ira Abramov wrote:

> Quoting Richard Sharpe, from the post of Wed, Jul 03, 2002 at 04:22:49AM +0930:
> 
> > Actually, one of the things we would like to support is a cluster of 
> > diskless Linux machines booting and serving all their stuff from a NAS 
> > using NFS or some other distributed file system protocol (not CIFS :-).
> 
> well, why not boot a ramdisk image taken off an iBoot or bootp server,
> and run all the files locally? do you really want to trust the NFS
> server to always be there?

Hmmm, OK, that is a good way to do things, and is essentially the way we 
currently install our FreeBSD blades. I guess that one objection is going 
to be that booting a 1000-node cluster is going to take some time, even 
with Gigabit, but then we could play games with using multicast for the 
basic /root image and build the /etc image dynamically and have each node 
grab that separately.

It won't be NFS though, we have our own DFS for that, and the cluster 
nodes will need it up for access to the file system during computation.
 
> > If you have a 1000-node cluster, managing separate root areas for each can 
> > become problematical. It seems that only /etc would need to be different, 
> > and if the mount command or the pathname management component understood 
> > variables, one could mount /etc from something like mndfs://server/etcs/$H 
> 
> when you find that distributed filesystem drop us a note. Exanet and
> other companies have been trying for a good one for a long time.

We have this sort of thing in the FS already, but the suggestion you made 
is going to be easier, I suspect, at least initially, than the engineering 
to introduce a separate mount point for /etc and have the kernel mount 
that separately.

> in any case, the /etc can be on the ramdrive - load a template etc and
> sed the differences for the specific machine, based on the IP is got
> via bootp.
 
Regards
-----
Richard Sharpe, rsharpe at ns.aus.com, rsharpe at samba.org, 
sharpe at ethereal.com, rsharpe at panasas.com




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