<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Sep 7, 2017 at 10:06 AM, Yaniv Kaul <span dir="ltr"><<a href="mailto:ykaul@redhat.com" target="_blank">ykaul@redhat.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"><br><div class="gmail_extra"><br><div class="gmail_quote"><span class="">On Wed, Sep 6, 2017 at 6:08 PM, Abi Askushi <span dir="ltr"><<a href="mailto:rightkicktech@gmail.com" target="_blank">rightkicktech@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div><div><div><div><div><div><div><div><div>For a first idea I use:<br></div><div><span style="font-family:monospace,monospace"><br></span></div><div><span style="font-family:monospace,monospace">dd if=/dev/zero of=testfile bs=1GB count=1</span></div></div></div></div></div></div></div></div></div></div></div></blockquote><div><br></div></span><div>This is an incorrect way to test performance, for various reasons:</div><div>1. You are not using oflag=direct , thus not using DirectIO, but using cache.</div><div>2. It's unrealistic - it is very uncommon to write large blocks of zeros (sometimes during FS creation or wiping). Certainly not 1GB</div><div>3. It is a single thread of IO - again, unrealistic for VM's IO.</div><div><br></div><div>I suggest using fio and such. See <a href="https://github.com/pcuzner/fio-tools" target="_blank">https://github.com/<wbr>pcuzner/fio-tools</a> for example.</div><span class=""><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div><div><div><div><div><div><div><div><div><br></div><div><br></div><div>When testing on the gluster mount point using above command I hardly get 10MB/s. (On the same time the network traffic hardly reaches 100Mbit). <br></div><div><br></div>When testing our of the gluster (for example at /root) I get 600 - 700MB/s. <br></div></div></div></div></div></div></div></div></div></div></blockquote><div><br></div></span><div>That's very fast - from 4 disks doing RAID5? Impressive (unless you use caching!). Are those HDDs or SSDs/NVMe?</div><span class=""><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div><div><div><div><div><div><div><div></div><div><br></div>When I mount the gluster volume with NFS and test on it I get 90 - 100 MB/s, (almost 10x from gluster results) which is the max I can get considering I have only 1 Gbit network for the storage. <br><br></div>Also, when using glusterfs the general VM performance is very poor and disk write benchmarks show that is it at least 4 times slower then when the VM is hosted on the same data store when NFS mounted. <br></div><div><br></div>I don't know why I hitting such a significant performance penalty, and every possible tweak that I was able to find out there did not make any difference on the performance. <br><br></div>The hardware I am using is pretty decent for the purposes intended:<br></div>3 nodes, each node having with 32 MB of RAM, 16 physical CPU cores, 2 TB of storage in RAID5 (4 disks), of which 1.5 TB are sliced for the data store of ovirt where VMs are stored. <br></div></div></div></div></div></blockquote></span></div></div></div></blockquote><div><br></div><div>I forgot to ask why are you using RAID 5 with 4 disks and not RAID 10? Same usable capacity, higher performance, same protection and faster recovery, I believe.</div><div>Y.</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><span class=""><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div><div><div></div></div></div></div></div></blockquote><div><br></div></span><div>You have not mentioned your NIC speeds. Please ensure all work well, with 10g.</div><div>Is the network dedicated for Gluster traffic? How are they connected?</div><span class=""><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div><div><div><br></div>The gluster configuration is the following: <br></div></div></div></div></blockquote><div><br></div></span><div>Which version of Gluster are you using?</div><span class=""><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div><div><br>Volume Name: vms<br>Type: Replicate<br>Volume ID: 4513340d-7919-498b-bfe0-d836b5<wbr>cea40b<br>Status: Started<br>Snapshot Count: 0<br>Number of Bricks: 1 x (2 + 1) = 3<br>Transport-type: tcp<br>Bricks:<br>Brick1: gluster0:/gluster/vms/brick<br>Brick2: gluster1:/gluster/vms/brick<br>Brick3: gluster2:/gluster/vms/brick (arbiter)<br>Options Reconfigured:<br>nfs.export-volumes: on<br>nfs.disable: off<br>performance.readdir-ahead: on<br>transport.address-family: inet<br>performance.quick-read: off<br>performance.read-ahead: off<br>performance.io-cache: off<br>performance.stat-prefetch: on<br></div></div></div></div></blockquote><div><br></div></span><div>I think this should be off.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div><div>performance.low-prio-threads: 32<br>network.remote-dio: off<br></div></div></div></div></blockquote><div><br></div><div>I think this should be enabled.</div><span class=""><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div><div>cluster.eager-lock: off<br>cluster.quorum-type: auto<br>cluster.server-quorum-type: server<br>cluster.data-self-heal-algorit<wbr>hm: full<br>cluster.locking-scheme: granular<br>cluster.shd-max-threads: 8<br>cluster.shd-wait-qlength: 10000<br>features.shard: on<br>user.cifs: off<br>storage.owner-uid: 36<br>storage.owner-gid: 36<br>network.ping-timeout: 30<br>performance.strict-o-direct: on<br>cluster.granular-entry-heal: enable<br>features.shard-block-size: 64MB<br></div></div></div></div></blockquote><div><br></div></span><div>I'm not sure if this should not be 512MB. I don't remember the last resolution on this.</div><div>Y.</div><span class=""><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div><div>performance.client-io-threads: on<br>client.event-threads: 4<br>server.event-threads: 4<br>performance.write-behind-windo<wbr>w-size: 4MB<br>performance.cache-size: 1GB<br><br></div>In case I can provide any other details let me know. <br></div></div></div></blockquote><div><br></div></span><div>What is your tuned profile?</div><span class=""><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div></div>At the moment I already switched to gluster based NFS but I have a similar setup with 2 nodes where the data store is mounted through gluster (and again relatively good hardware) where I might check any tweaks or improvements on this setup. <br><br></div>Thanx<br><div><br></div></div><div class="m_-2474129227919145367gmail-m_-571567959162763644HOEnZb"><div class="m_-2474129227919145367gmail-m_-571567959162763644h5"><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Sep 6, 2017 at 5:32 PM, Yaniv Kaul <span dir="ltr"><<a href="mailto:ykaul@redhat.com" target="_blank">ykaul@redhat.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote"><span>On Wed, Sep 6, 2017 at 3:32 PM, Abi Askushi <span dir="ltr"><<a href="mailto:rightkicktech@gmail.com" target="_blank">rightkicktech@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div><div><div><div><div><div><div><div><div>Hi All,<br><br></div>I've playing with ovirt self hosted engine setup and I even use it to production for several VM. The setup I have is 3 server with gluster storage in replica 2+1 (1 arbiter). <br></div>The data storage domain where VMs are stored is mounted with gluster through ovirt. The performance I get for the VMs is very low and I was thinking to switch and mount the same storage through NFS instead of glusterfs. <br></div></div></div></div></div></div></div></div></div></blockquote><div><br></div></span><div>I don't see how it'll improve performance.</div><div>I suggest you share the gluster configuration (as well as the storage HW) so we can understand why the performance is low.</div><div>Y.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><span><div dir="ltr"><div><div><div><div><div><div><div><div><br></div>The only think I am hesitant is how can I ensure high availability of the storage when I loose one server? I was thinking to have at /etc/hosts sth like below: <br><br></div>10.100.100.1 nfsmount<br></div>10.100.100.2 nfsmount<br></div>10.100.100.3 nfsmount<br><br></div>then use nfsmount as the server name when adding this domain through ovirt GUI. <br></div>Are there any other more elegant solutions? What do you do for such cases?<br></div>Note: gluster has the back-vol-file option which provides a lean way to have redundancy on the mount point and I am using this when mounting with glusterfs. <br><br></div>Thanx<br></div>
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