Re: [ovirt-users] Recommended setup for a FC based storage domain

/etc/libvirt/libvirtd.conf and /etc/vdsm/logger.conf , but unfortunately maybe I've jumped to conclusions, last weekend, that very same thin provisioned vm was running a simple export for 3hrs before I've killed the process. But I wondered: 1. The process that runs behind the export is qemu-img convert (from raw to raw), and running iotop shows that every three or four seconds it reads 10-13 MBps and then idles for a few seconds. Run the numbers on 100GB (why is he covering the entire 100 of 15GB used on thin volume I still don't get it) and you get precisely 3-4 hrs estimated time remaining. 2. When I run export with SPM on a node that doesn't have any vm's running, export finishes for aprox. 30min (iotop shows 40-70MBps read speed constantly) 3. Renicing I/O priority of the qemu-img process as well as the CPU priority gave no results, it was still runing slow beyond any explanation. Debug logs showed nothing of interest, so I disabled anything above warning and it suddenly accelerated the export, so I've connected the wrong dots. On 06/10/2014 11:18 AM, Andrew Lau wrote: > Interesting, which files did you modify to lower the log levels? > > On Tue, Jun 3, 2014 at 12:38 AM, <combuster(a)archlinux.us&gt; wrote: >> One word of caution so far, when exporting any vm, the node that acts >> as SPM >> is stressed out to the max. I releived the stress by a certain margin >> with >> lowering libvirtd and vdsm log levels to WARNING. That shortened out the >> export procedure by at least five times. But vdsm process on the SPM >> node is >> still with high cpu usage so it's best that the SPM node should be >> left with a >> decent CPU time amount to spare. Also, export of VM's with high vdisk >> capacity >> and thin provisioning enabled (let's say 14GB used of 100GB defined) >> took >> around 50min over a 10Gb ethernet interface to a 1Gb export NAS >> device that >> was not stressed out at all by other processes. When I did that >> export with >> debug log levels it took 5hrs :( >> >> So lowering log levels is a must in production enviroment. I've >> deleted the >> lun that I exported on the storage (removed it first from ovirt) and >> for the >> next weekend I am planing to add a new one, export it again on all >> the nodes >> and start a few fresh vm installations. Things I'm going to look for are >> partition alignment and running them from different nodes in the >> cluster at >> the same time. I just hope that not all I/O is going to pass through >> the SPM, >> this is the one thing that bothers me the most. >> >> I'll report back on these results next week, but if anyone has >> experience with >> this kind of things or can point to some documentation would be great. >> >> On Monday, 2. June 2014. 18.51.52 you wrote: >>> I'm curious to hear what other comments arise, as we're analyzing a >>> production setup shortly. >>> >>> On Sun, Jun 1, 2014 at 10:11 PM, <combuster(a)archlinux.us&gt; wrote: >>>> I need to scratch gluster off because setup is based on CentOS 6.5, so >>>> essential prerequisites like qemu 1.3 and libvirt 1.0.1 are not met. >>> Gluster would still work with EL6, afaik it just won't use libgfapi and >>> instead use just a standard mount. >>> >>>> Any info regarding FC storage domain would be appreciated though. >>>> >>>> Thanks >>>> >>>> Ivan >>>> >>>> On Sunday, 1. June 2014. 11.44.33 combuster(a)archlinux.us wrote: >>>>> Hi, >>>>> >>>>> I have a 4 node cluster setup and my storage options right now are >>>>> a FC >>>>> based storage, one partition per node on a local drive (~200GB >>>>> each) and >>>>> a >>>>> NFS based NAS device. I want to setup export and ISO domain on the >>>>> NAS >>>>> and >>>>> there are no issues or questions regarding those two. I wasn't >>>>> aware of >>>>> any >>>>> other options at the time for utilizing a local storage (since >>>>> this is a >>>>> shared based datacenter) so I exported a directory from each >>>>> partition >>>>> via >>>>> NFS and it works. But I am little in the dark with the following: >>>>> >>>>> 1. Are there any advantages for switching from NFS based local >>>>> storage to >>>>> a >>>>> Gluster based domain with blocks for each partition. I guess it >>>>> can be >>>>> only >>>>> performance wise but maybe I'm wrong. If there are advantages, are >>>>> there >>>>> any tips regarding xfs mount options etc ? >>>>> >>>>> 2. I've created a volume on the FC based storage and exported it >>>>> to all >>>>> of >>>>> the nodes in the cluster on the storage itself. I've configured >>>>> multipathing correctly and added an alias for the wwid of the LUN >>>>> so I >>>>> can >>>>> distinct this one and any other future volumes more easily. At >>>>> first I >>>>> created a partition on it but since oVirt saw only the whole LUN >>>>> as raw >>>>> device I erased it before adding it as the FC master storage >>>>> domain. I've >>>>> imported a few VM's and point them to the FC storage domain. This >>>>> setup >>>>> works, but: >>>>> >>>>> - All of the nodes see a device with the alias for the wwid of the >>>>> volume, >>>>> but only the node wich is currently the SPM for the cluster can see >>>>> logical >>>>> volumes inside. Also when I setup the high availability for VM's >>>>> residing >>>>> on the FC storage and select to start on any node on the cluster, >>>>> they >>>>> always start on the SPM. Can multiple nodes run different VM's on the >>>>> same >>>>> FC storage at the same time (logical thing would be that they can, >>>>> but I >>>>> wanted to be sure first). I am not familiar with the logic oVirt >>>>> utilizes >>>>> that locks the vm's logical volume to prevent corruption. >>>>> >>>>> - Fdisk shows that logical volumes on the LUN of the FC volume are >>>>> missaligned (partition doesn't end on cylindar boundary), so I >>>>> wonder if >>>>> this is becuase I imported the VM's with disks that were created >>>>> on local >>>>> storage before and that any _new_ VM's with disks on the fc >>>>> storage would >>>>> be propperly aligned. >>>>> >>>>> This is a new setup with oVirt 3.4 (did an export of all the VM's >>>>> on 3.3 >>>>> and after a fresh installation of the 3.4 imported them back >>>>> again). I >>>>> have room to experiment a little with 2 of the 4 nodes because >>>>> currently >>>>> they are free from running any VM's, but I have limited room for >>>>> anything else that would cause an unplanned downtime for four virtual >>>>> machines running on the other two nodes on the cluster (currently >>>>> highly >>>>> available and their drives are on the FC storage domain). All in >>>>> all I >>>>> have 12 VM's running and I'm asking on the list for advice and >>>>> guidance >>>>> before I make any changes. >>>>> >>>>> Just trying to find as much info regarding all of this as possible >>>>> before >>>>> acting upon. >>>>> >>>>> Thank you in advance, >>>>> >>>>> Ivan