On 01/06/2011 06:52 PM, Christopher Hawkins wrote:
This is not scalable to more than a few servers, but one possibility for this type of setup is to use LVS in conjunction with Gluster storage. Say there were 3 gluster storage nodes doing a 3x replicate. One of them (or a small 4th server) could have a virtual IP that accepts inbound NFS requests and then forwards them to one of the 3 "real server" gluster storage nodes. Each would be listening on NFS, would have all the files, and would be able to serve directly and respond with the IP that the packet was originally addressed to.
If I am understanding what you are describing correctly, you are talking about using LVS in direct routing mode. That's pretty similar to what I was describing. This would be scalable right up to the point where the LB runs out of bandwidth to handle client responses. This is probably fine for situations where clients are heavy readers. It wouldn't scale at all of the clients are heavy writers.
What I was talking about in the previous email is having each service node act as a LB itself, and able to load balance traffic to other nodes based on which the actual files reside - it'd have to be a GlusterFS translator because it would have to look up what node has the file and pass the request to that node.
It would essentially require a GlusterFS translator that combines LVS functionality with the GLFS interfaces to establish which node has the requested file.
And if I were to find myself with a month or two of coding time on my hands I might even be tempted to implement such a thing - but don't hold your breath, it's unlikely to happen any time soon. :)
Gordan
