<div dir="ltr">Hello Lindsay,<div><br></div><div>From personal experience: A two node volume can get you into trouble when one of the nodes goes down unexpectedly/crashes. At the very least, you should have an arbiter volume (introduced in Gluster 3.7) on a separate physical node.<div><br></div><div>We are running oVirt VM's on top of a two node Gluster cluster and a few months ago, I ended up transferring several terabytes from one node to the other because it was the fastest way to resolve the split-brain issues after a crash of Gluster on one of the nodes. In effect, the second node did not give us any redundancy, because the vm-images in split-brain would not be available for writes.</div><div><br></div><div>I don't think 4 GB is enough RAM, especially if you have a large L2ARC: every L2ARC entry needs an entry in ARC as well, which is always in RAM. RAM is relatively cheap nowadays, so go for at least 16 or 32.</div><div><br></div><div>You should also count the number of spindles you have and have it not exceed the number of VM's you're running much to get decent disk IO performance. </div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On 30 September 2015 at 07:00, Lindsay Mathieson <span dir="ltr"><<a href="mailto:lindsay.mathieson@gmail.com" target="_blank">lindsay.mathieson@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><div><div><div><div><div><div>I'm revisiting Gluster for the purpose of hosting Virtual Machine images (KVM). I was considering the following configuration<br><br></div>2 Nodes<br></div>- 1 Brick per node (replication = 2)<br></div><div>- 2 * 1GB Eth, LACP Bonded<br></div>- Bricks hosted on ZFS<br></div><div>- VM Images accessed via Block driver (gfapi)<br></div><br>ZFS Config:<br></div>- Raid 10<br></div>- SSD SLOG and L2ARC<br></div>- 4 GB RAM<br></div> - Compression (lz4)<br><div><br><div><div><div><div><div>Does that seem like an sane layout?<br><br></div><div>Question: With the gfapi driver, does the vm image appear as a file on the host (zfs) file system?<br></div><div><br clear="all"><div><div><div><br></div><div>Background: I currently have our VM's hosted on Ceph using a similar config as above, minus zfs. I've found that the performance for such a small setup is terrible, the maintenance headache is high and when a drive drops out, the performance gets *really* bad. Last time I checked, gluster was much slower at healing large files than ceph, I'm hoping that has improved :)<span class="HOEnZb"><font color="#888888"><br></font></span></div><span class="HOEnZb"><font color="#888888"><div><br>-- <br><div>Lindsay</div>
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