similar to: changing to cache='none' on the fly?

Hi, I've seen that in the past, libvirt couldn't start VMs when the disk image was stored on a file system that doesn't support direct I/O having the 'cache=none' configuration [0]. On the KubeVirt project, we have some storage tests on a particular provider which does just that - try to create / start a VM whose disk is on tmpfs and whose definition features

hi, i tried to add a 'cache' argument to the 'driver' element in my domainxml for qemu/kvm. i tried adding cache="none" as well as "writethrough" and "writeback", but every time i get these errors: libvirtError: internal error process exited while connecting to monitor: char device redirected to /dev/pts/1 qemu: could not open disk image

The new cache=none mode is misleading since it does not avoid usage of the page cache. When using shared storage, we may get stale data from the page cache. When writing, we flush after every write which is inefficient and unneeded. Rename the cache modes to: - writeback - write complete when the system call returned, and the data was copied to the page cache. - writethrough - write completes

On Sun, Aug 9, 2020 at 12:28 AM Richard W.M. Jones <rjones@redhat.com> wrote: > > On Sat, Aug 08, 2020 at 01:24:02AM +0300, Nir Soffer wrote: > > The new cache=none mode is misleading since it does not avoid usage of > > the page cache. When using shared storage, we may get stale data from > > the page cache. When writing, we flush after every write which is > >

Document a per-disk cache option in the xl config file to allow users to select the cache mode that the backend should use to open the disk file or device. Document backend options that are part of the vbd xenstore interface. The existing "mode" and "device-type" as well as the new "cache". Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

Hi, a small update on this. We have migrated the virtualized host to use the virtio drivers and now the drive performance is improved so that we can see a constant transfer rate. Before it used to be the same rate but regularly dropped to a few bytes/sec for a few seconds and then was fast again. However we still observe that the following fails regularily: $ virsh snapshot-create-as --domain

Hi Eric, Thanks for the info. I see the value in this, but it isn't quite what I was looking for. Basically what I want to do is to switch between snapshots quickly. For instance, I am currently working on designing a HA SQL implementation with failover. So right now I have 5 VM's running postgresql as a replication group. I am trying a lot of different things and often have to take a

Hello, I did a virsh snapshot-create-as --domain meta sn1 --diskspec vda,file=/var/lib/libvirt/images/meta-sn1.qcow2 --disk-only --atomic --no-metadata Then I successfully blockcommitted 2 disks: virsh blockcommit meta vda --active --verbose --pivot virsh blockcommit meta vdb --active --verbose --pivot But when doing virsh blockcommit meta vdc --active --verbose --pivot I got: Block commit:

On Fri, Jun 30, 2017 at 09:23:29 -0400, Doug Hughes wrote: > On Jun 30, 2017 6:22 AM, "Peter Krempa" <pkrempa@redhat.com> wrote: > > On Fri, Jun 30, 2017 at 12:05:47 +0200, Peter Krempa wrote: > > > On Thu, Jun 22, 2017 at 11:02:41 -0400, Doug Hughes wrote: [...] > file or directory > > $ virsh blockcommit --active --pivot fedora23 vda > > >

Hello, it happened with another VM: # virsh snapshot-create-as --domain rasa sn1 --diskspec vda,file=/var/lib/libvirt/images/rasa-sn1.qcow2 --disk-only --atomic --no-metadata # virsh blockcommit rasa vda --active --verbose --pivot Block commit: [100 %]error: failed to pivot job for disk vda error: block copy still active: disk 'vda' not ready for pivot yet # virsh domblklist rasa

Thank you Eric, On 2014-02-05 17:23, Eric Blake wrote: > Yes, live storage migration is possible; although at the moment, qemu is > lacking a way to restart the operation if it fails midstream, so libvirt > only allows the operation if you are willing to temporarily make your > guest transient. What does this mean? Will I loose anything if - for example - there is not enough space on

Hi all, I can''t find any good talk about this subject and would like some insights and advices on the cache side in xen. I discovered that a domO power outage can lead to a severe filesystem corruption of the domUs. The domO is a dual disk dell server with a PERC controler in writethrough cache mode, the disk cache is disabled, the scheduler in the domO/domU is NOOP, the domO is holding

Am 13.10.14 16:25, schrieb Eric Blake: > On 10/13/2014 03:56 AM, Thomas Stein wrote: >> Hello. >> >>> blockcommit vm1 vda --active --verbose --pivot >> >> That's where libvirt stops working at the moment, right? >> >> virsh # blockcommit puppet-test vda --active --verbose --pivot >> error: unsupported flags (0x4) in function

Hi, Is it possible to "pivot" to a new image without doing blockcopy or blockpull? I know how to use snapshots and blockpull to create a new image and pivot to using it live, but what I would like to do is to have a VM switch from using imageA.qcow2 to image2.qcow2 while running. I don't see why this wouldn't be possible since some of the existing libvirt tools can do this when

On Fri, Jun 30, 2017 at 10:41:25 -0400, doug.hughes@keystonenap.com wrote: > sorry about top post, tablet mail client... > > brilliant! that did it! Any idea what happened to cause it to partially fail and get into this state? virsh blockcommit --pivot is actually 3 operations in sequence: 1) initiate the commit job 2) wait till it finishes 3) initiate the pivot job (this is

On Wednesday 07 January 2015 09:46:09 Eric Blake wrote: > On 01/07/2015 07:19 AM, Thomas Stein wrote: > > Hello. > > > > I'm seeing this error while doing a backup of a VM. > > > > + virsh blockcommit kaltura vda --active --verbose --pivot > > Block Commit: [100 %]error: failed to pivot job for disk vda > > error: internal error: unable to execute

Hi, Recently We've upgraded some KVM hosts from Fedora 29 to Fedora 30 and now experience broken VM configurations on filesystem after virsh blockcommit. Commands "virsh dumpxml ..." and "virsh dumpxml --inactive ..." is showing diffrent configuration than the one on filesystem. In case of restart libvirtd or system reboot, there are broken VM xml configurations on

Hi guys, When performing live merge, in few cases, we see the following exception: Traceback (most recent call last): File "/usr/lib/python2.7/site-packages/vdsm/utils.py", line 736, in wrapper return f(*a, **kw) File "/usr/share/vdsm/virt/vm.py", line 5278, in run self.tryPivot() File "/usr/share/vdsm/virt/vm.py", line 5247, in tryPivot ret =

Hello. > blockcommit vm1 vda --active --verbose --pivot That's where libvirt stops working at the moment, right? virsh # blockcommit puppet-test vda --active --verbose --pivot error: unsupported flags (0x4) in function qemuDomainBlockCommit cheers t.

Hello. I'm seeing this error while doing a backup of a VM. + virsh blockcommit kaltura vda --active --verbose --pivot Block Commit: [100 %]error: failed to pivot job for disk vda error: internal error: unable to execute QEMU command 'block-job-complete': The active block job for device 'drive-virtio-disk0' cannot be completed I'm on qemu 2.2.0 and libvirt-1.2.11. Does