Tuesday, June 26, 2007

Vservers can improve you life (if not your diet)

Denis, Matt, and I have been talking about lots of different architectures we could use to improve some of the infrastructure at eclipse.org. We have some miscellaneous machines which aren't part of the core infrastructure but do some important jobs. And then we have a couple of host servers that hold vservers for some of the projects, which are mostly full and which are hosted on local disks.

We don't have a lot of rack space, or room for lots of physical servers but we keep finding that we want separate servers for various things, and that we have whole servers sometimes dedicated to things which don't really need to occupy an entire server. How do you re-allocate all of that without making a huge mess? Enter vservers!

In reading through lots of high availability documentation while working on our NFS problems awhile ago, Denis and I both read about a nice idea Novell used in one of their demonstrations. They had several vserver images hosted on a share and used multiple vserver host machines to mount the share. Their idea was to have the vserver reloaded on another server in the event that the original host server crashed, thus providing some high-availability for the vserver. For the non-critical servers we're talking about we don't need high availability. But if we use that architecture of interchangeable vservers and images hosted on a share, we can move vservers around between hosts on the same subnet however we like to best suit resources without affecting a thing about how they run. This is not a new idea, but it sure is a good one. I hadn't been thinking about it in this context, but talking to Denis today we struck on that as a good strategy. We haven't made any firm plans yet about which servers will move, but you can bet we'll be employing more vservers in the eclipse.org infrastructure soon.


Anonymous Gunnar said...

Yepp. It sounds like marketing but virtualization is the key. For example, we too have a big machine here just to play the DC role. Now, with VMWare server on it it also plays a lot of other roles and it still has resources available. :)

9:51 PM  
Anonymous Denis Roy said...

We've been really happy with Xen's stability. We didn't want to run anything super-important on it at first, but it seems to be supporting the project vservers just fine.

3:22 AM  

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