Bill, Appreciate the feedback and would be interested to hear some of your results. I'm a bit worried about what i'm seeing so far on a very stock 3 node HCI setup. 8mb/sec on that dd test mentioned in the original post from within a VM (which may be explained by bad testing methods or some other configuration considerations).. but what is more worrisome to me is that I tried another dd test to time creating a 32GB file, it was taking a long time so I exited the process and the VM basically locked up on me, I couldn't access it or the console and eventually had to do a hard shutdown of the VM to recover.
I don't plan to host many VMs, probably around 15. They aren't super demanding servers but some do read/write big directories such as working with github repos and large node_module folders, rsyncs of fairly large dirs etc. I'm definitely going to have to do a lot more testing before I can be assured enough to put any important VMs on this cluster. - James On Thu, Aug 2, 2018 at 1:54 PM, William Dossett <william.doss...@gmail.com> wrote: > I usually look at IOPs using IOMeter… you usually want several workers > running reads and writes in different threads at the same time. You can > run Dynamo on a Linux instance and then connect it to a window GUI running > IOMeter to give you stats. I was getting around 250 IOPs on JBOD sata > 7200rpm drives which isn’t bad for cheap and cheerful sata drives. > > > > As I said, I’ve worked with HCI in VMware now for a couple of years, > intensely this last year when we had some defective Dell hardware and > trying to diagnose the problem. Since then the hardware has been > completely replaced with all flash solution. So when I got the all flash > solution I used IOmeter on it and was only getting around 3000 IOPs on > enterprise flash disks… not exactly stellar, but OK for one VM. The trick > there was the scale out. There is a VMware Fling call HCI Bench. Its very > cool in that you spin up one VM and then it spawns 40 more VMs across the > cluster. I could then use VSAN observer and it showed my hosts were > actually doing 30K IOPs on average which is absolutely stellar > performance. > > > > Anyway, moral of the story there was that your one VM may seem like its > quick, but not what you would expect from flash… but as you add more VMs > in the cluster and they are all doing workloads, it scales out beautifully > and the read/write speed does not slow down as you add more loads. I’m > hoping that’s what we are going to see with Gluster. > > > > Also, you are using mb nomenclature below, is that Mb, or MB? I am sort > of assuming MB megabytes per second… it does not seem very fast. I’m > probably not going to get to work more on my cluster today as I’ve got > other projects that I need to get done on time, but I want to try and get > some templates up and running and do some more testing either tomorrow or > this weekend and see what I get in just basic writing MB/s and let you know. > > > > Regards > > Bill > > > > > > *From:* Jayme <jay...@gmail.com> > *Sent:* Thursday, August 2, 2018 8:12 AM > *To:* users <users@ovirt.org> > *Subject:* [ovirt-users] Tuning and testing GlusterFS performance > > > > So I've finally completed my first HCI build using the below configuration: > > > > 3x > > Dell PowerEdge R720 > > 2x 2.9 GHz 8 Core E5-2690 > > 256GB RAM > > 2x250gb SSD Raid 1 (boot/os) > > 2x2TB SSD jbod passthrough (used for gluster bricks) > > 1Gbe Nic for management 10Gbe nic for Gluster > > > > Using Replica 3 with no arbiter. > > > > Installed the latest version of oVirt available at the time 4.2.5. > Created recommended volumes (with an additional data volume on second SSD). > Not using VDO > > > > First thing I did was setup glusterFS network on 10Gbe and set it to be > used for glusterFS and migration traffic. > > > > I've setup a single test VM using Centos7 minimal on the default "x-large > instance" profile. > > > > Within this VM if I do very basic write test using something like: > > > > dd bs=1M count=256 if=/dev/zero of=test conv=fdatasync > > > > I'm seeing quite slow speeds, only 8mb/sec. > > > > If I do the same from one of the hosts gluster mounts i.e. > > > > host1: /rhev/data-center/mnt/glusterSD/HOST:data > > > > I get about 30mb/sec (which still seems fairly low?) > > > > Am I testing incorrectly here? Is there anything I should be tuning on > the Gluster volumes to increase performance with SSDs? Where can I find > out where the bottle neck is here, or is this expected performance of > Gluster? >
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