I replaced the SSD intent log drive with an NVME drive, and the system is much more stable now. *David Johnson* *Director of Development, Maxis Technology* 844.696.2947 ext 702 (o) | 479.531.3590 (c) <https://www.linkedin.com/in/pojoguy/> <https://maxistechnology.com/wp-content/uploads/vcards/vcard-David_Johnson... <https://maxistechnology.com/> *Follow us:* <https://www.linkedin.com/company/maxis-tech-inc/> On Thu, May 27, 2021 at 5:57 PM David Johnson < djohnson(a)maxistechnology.com&gt; wrote: > Hi ovirt gurus, > > This is an interesting issue, one I never expected to have. > > When I push high volumes of writes to my NAS, I will cause VM's to go > into a paused state. I'm looking at this from a number of angles, including > upgrades on the NAS appliance. > > I can reproduce this problem at will running a centos 7.9 VM on Ovirt 4.5. > > *Questions:* > > 1. Is my analysis of the failure (below) reasonable/correct? > > 2. What am I looking for to validate this? > > 3. Is there a configuration that I can set to make it a little more > robust while I acquire the hardware to improve the NAS? > > > *Reproduction:* > > Standard test of file write speed: > > [root@cen-79-pgsql-01 ~]# dd if=/dev/zero of=./test bs=512k count=4096 > oflag=direct > 4096+0 records in > 4096+0 records out > 2147483648 bytes (2.1 GB) copied, 1.68431 s, 1.3 GB/s > > > Give it more data > > [root@cen-79-pgsql-01 ~]# dd if=/dev/zero of=./test bs=512k count=12228 > oflag=direct > 12228+0 records in > 12228+0 records out > 6410993664 bytes (6.4 GB) copied, 7.22078 s, 888 MB/s > > > The odds are about 50/50 that 6 GB will kill the VM, but 100% when I hit > 8 GB. > > *Analysis:* > > What I think appears to be happening is that the intent cache on the NAS > is on an SSD, and my VM's are pushing data about three times as fast as the > SSD can handle. When the SSD gets queued up beyond a certain point, the NAS > (which places reliability over speed) says "Whoah Nellie!", and the VM > chokes. > > > *David Johnson* > _______________________________________________ Users mailing list -- users(a)ovirt.org To unsubscribe send an email to users-leave(a)ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/TL22ZDND4FS...

What happens if you define a tmpfs and then create the qemu disk ontop of that ramdisk. Does qemu hang again ?

Following up on this old email chain: *" What happens if you define a tmpfs and then create the qemu disk ontop of that ramdisk.* *Does qemu hang again ?"* I'm not primarily a linux admin, so I need some assistance here. 1. Are you creating the tmpfs on the host or on the VM? 2. What exactly do you mean by "create the qemu disk ontop of that ramdisk" ? Please use large crayons - I know this will be obvious to people who live in the linux administration world, but I'm just on the fringes of that world and a relative novice. Ideally, I'd like a link to step by step instructions for retrofitting an existing installation like this. Thank you! *David Johnson* On Thu, Sep 23, 2021 at 2:15 PM Strahil Nikolov <hunter86_bg(a)yahoo.com&gt; wrote: > What happens if you define a tmpfs and then create the qemu disk ontop of > that ramdisk. > Does qemu hang again ? > > Best Regards, > Strahil Nikolov > > On Thu, Sep 23, 2021 at 18:25, Shantur Rathore > <shantur.rathore(a)gmail.com&gt; wrote: > _______________________________________________ > Users mailing list -- users(a)ovirt.org > To unsubscribe send an email to users-leave(a)ovirt.org > Privacy Statement: https://www.ovirt.org/privacy-policy.html > oVirt Code of Conduct: > https://www.ovirt.org/community/about/community-guidelines/ > List Archives: > > https://lists.ovirt.org/archives/list/users@ovirt.org/message/CR5THX22KMQ... > >