Thanks for your response, Nathan. 3. Use Gluster for redundancy instead of RAID. It would be nice if I can >> lose any single hard drive and/or entire server and still have access to >> 100% of all the data in the pool. In this sort of setup, is it possible >> to >> limit the number of copies of data to 2 or 3, or if I have 10 machines, >> will >> I be forced to have 10 copies of the data? >> > > Sure, you can do almost anything you want, today there is not RAID like > functionality, but that is on the roadmap. We use "replicate" on pairs of > servers and then unify them together with "distribute". > > An example of our 4 node test cluster is: > > http://share.robotics.net/glusterfs.vol > http://share.robotics.net/glusterfsd.vol > If you replicate pairs of servers, how come you're still using RAID 6? > > > 4. Get good performance. Will i get acceptable performance through >> gigabit >> ethernet, or do I need 10 gigabit ethernet or infiniband to have something >> decent? Because I want a configuration where each machine is both a >> client >> and a server, will performance degrade as I add more machine such that the >> network needs to handle n^2 connections, where n is the number of servers? >> Or will performance improve because data will be striped across a lot of >> machines? >> > > Infiniband is totally worth it, stuff is low cost (even can pick it up on > ebay like we did) and has much lower latency then ethernet. > > Now as far as "good performance" this is where I am having the most issues > with Gluster. To make it work with xen you need --disable-direct-io-mode > when you start up glusterfs. I am not saying this is the best way to test, > but if you "dd if=/dev/zero of=test bs=1G count=8" we get: > > XFS partition on 3ware 378 MB/s Not bad for writes! > Gluster default 110 MB/s Expected more... > Gluster disable-direct-io-mode 22 MB/s OUCH!!! > > The other issue we have is that we have so far only been able to use zen > with file and not tap:aio (it stars, but never finishes domu boot). > I saw the note in the technical faq about --disable-direct-io-mode. What does this do, and why is it needed to perform Xen migration? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://zresearch.com/pipermail/gluster-users/attachments/20090302/6a7b58eb/attachment.htm>
