Re: [Vserver] /vservers as an nfs mount?

From: Herbert Poetzl <>
Date: Wed 26 Apr 2006 - 10:44:32 BST
Message-ID: <>

On Wed, Apr 26, 2006 at 07:00:21PM +1200, Sam Vilain wrote:
> Chuck wrote:
>> we are completely restructuring our entire physical network around
>> the vserver concept.
>> it has proven itself in stability and performance in production to
>> the point we no longer see the need for dedicated servers except in
>> the most demanding instances (mostly our email server which cannot
>> be run as a guest until there is no slow down using > 130 ip addresses).

could you describe what scheme is behind those 130 ips
in your case? I'm trying to get an idea what addresses
such large-ip systems typically use ...
>> in our network restructuring, we wish to use our large storage
>> nfs system and place all the vserver guests on that sharing those
>> directories to be mounted on the proper dual opteron machine front
>> end as /vservers.
>> i am seriously thinking of also making /etc/vservers an nfs mount so
>> that each host configuration and guests live in a particular area on
>> the nfs to make switching machines a breeze if so needed.

>> does anyone see a problem with this idea? we will be using dual GB
>> nics into this nfs system in a pvtnet from each machine to facilitate
>> large amounts of data flow. public ip space will still use 100mb
>> nics.

that is basically what lycos is doing, and together with
them we implemented the xid tagging over nfs (requires
a patched filer though), which seems to work reasonably
fine ...
>> if this can work efficiently (most of our guests are not disk i/o
>> bound.. those with ultra heavy disk i/o will live on each front end
>> machine), we can consolidate more than 100 machines into 2 front end
>> machines and one SAN system. This would free enough rack space that
>> if we don't need any dedicated
>> machines in the future we could easily add more than 1500 servers in
>> host/guest config in the same space 100 took up. it would also hugely
>> simplify backups and drop our electric bill in half or more.

yes, just requires really sensitive tuning, otherwise
the nfs will be the bottleneck

> Nice idea, certainly NFS is right for /etc/vservers, but consider using
> a network block device, like iSCSI or ATA over Ethernet for the
> filesystems used by vservers themselves. You'll save yourself a lot of
> headaches and the thing will probably run a *lot* faster.

this is a viable alternative too, at least iSCSI and AOE
was already tested with Linux-VServer, so it should work

> Unification would be impractical on top of all of this, but this is
> probably not a huge problem.

why would that be so? if it is the same block device, the
filesystem on-top can as well use unification, not across
different filesystems though ...


> Sam.
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Received on Wed Apr 26 10:44:59 2006

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