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1612 discussions

KVM backup
by Gokan Atmaca 01 Aug '20

01 Aug '20

Hello I take backups while virtual machines are running live. For this, first I takes snapshot. Then I back up the original disk. But when I look at the snapshot list (1595157757,1595162592). I see that it is passive. I cannot delete them either. What would be the reason ? Name Creation Time State ------------------------------------------------------------ 1595157757 2020-07-19 14:22:37 +0300 disk-snapshot 1595162592 2020-07-19 15:43:12 +0300 disk-snapshot Error: error: Failed to delete snapshot 1595162592 error: unsupported configuration: deletion of 1 external disk snapshots not supported yet Thanks.

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oVirt 2020 online conference - free registration now open
by Sandro Bonazzola 15 Jul '20

15 Jul '20

It is our pleasure to renew our invite to oVirt 2020 online conference and announce free registration <https://www.eventbrite.it/e/ovirt-2020-online-conference-registration-11198…> is now open. The conference,organized by oVirt community, will take place online on Monday, September 7th 2020! You can read updated information about the conference at https://blogs.ovirt.org/ovirt-2020-online-conference/ A kind reminder that if you'd like to present at the conference, the deadline for the presentation proposal is July 26th 2020. -- Sandro Bonazzola MANAGER, SOFTWARE ENGINEERING, EMEA R&D RHV Red Hat EMEA <https://www.redhat.com/> sbonazzo(a)redhat.com <https://www.redhat.com/> *Red Hat respects your work life balance. Therefore there is no need to answer this email out of your office hours.*

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Pushing real machines into KVM/Qemu
by Philip Prindeville 07 Jul '20

07 Jul '20

Hi all, I took a real Core 2 machine (T7200… whose motherboard was starting to die…) running Fedora 29 and dd’d the SSD over to my KVM server, then created a VM using “create from existing image”. After some tweaking, including setting the disk type to “SATA” from “Virtio”, I got it working. Is there a fixed recipe for virtualizing CentOS/Fedora/RHEL instances into running VM’s on KVM/Qemu? Like re-running dracut and adding any particular drivers, etc? It works, but I don’t know how efficient the emulation is. The host hardware has IGB NIC’s, and I’m using “hostdev” as the network type, so that seems to be working well enough with the “igbvf” driver. Any tips would be appreciated. Thanks!

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oVirt 2020 online conference
by Sandro Bonazzola 29 Jun '20

29 Jun '20

Sandro Bonazzola <sbonazzo(a)redhat.com> 09:54 (1 ora fa) a users, oVirt, Ccn: announce, Ccn: board, Ccn: Discussion It is our pleasure to invite you to oVirt 2020 online conference. The conference,organized by oVirt community, will take place online on Monday, September 7th 2020! oVirt 2020 is a free conference for oVirt community project users and contributors coming to a web browser near you! There is no admission or ticket charge for this event. However, you will be required to complete a free registration. Watch https://blogs.ovirt.org/ovirt-2020-online-conference/ for updates about registration. Talks, presentations and workshops will all be in English. We encourage students and new graduates as well as professionals to submit proposals to oVirt conferences. We will be looking for talks and discussions across virtualization, and how oVirt 4.4 can effectively solve user issues around: - Upgrade flows - New features - Integration with other projects - User stories The deadline to submit abstracts is July 26th 2020. To submit your abstract, please click on the following link: submission form <https://forms.gle/1RDUwPGKobJfKhaYA> More information are available at https://blogs.ovirt.org/ovirt-2020-online-conference/ Thanks, -- Sandro Bonazzola MANAGER, SOFTWARE ENGINEERING, EMEA R&D RHV Red Hat EMEA <https://www.redhat.com/> sbonazzo(a)redhat.com <https://www.redhat.com/> *Red Hat respects your work life balance. Therefore there is no need to answer this email out of your office hours. <https://mojo.redhat.com/docs/DOC-1199578>*

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Re: [CentOS-virt] very low performance of Xen guests
by Manuel Wolfshant 18 Jun '20

18 Jun '20

On 6/15/20 5:40 PM, Stephen John Smoogen wrote: > > > On Mon, 15 Jun 2020 at 09:42, Manuel Wolfshant > <wolfy(a)nobugconsulting.ro <mailto:wolfy@nobugconsulting.ro>> wrote: > > On 6/15/20 2:46 PM, Stephen John Smoogen wrote: > > I got inspired by Adi's earlier suggestion and after reading > https://access.redhat.com/articles/3311301 I've tried today all > variants of disabling the spectre mitigations. Whatever I do, > immediately after a reboot, yum reinstall kernel does not take > less than 5 minutes :( It goes down to 2 min if I repeat the > operation afterwards so I guess some caching kicks in. I will try > later today the kernels from elrepo and maybe even xen.crc.id.au > <http://xen.crc.id.au> ( I kind of hate the "disable selinux" > recommendation from the install page so I postponed it in the hope > of other solution ). > > > > If you can do a full reinstall, could you see if a KVM host/guest > combo has the same problem? That would at least point the finger more > firmly at VT, spectre or something else. > > I finally managed to install a fresh KVM host / guest pair on an identical blade ( HS21XM, 64 GB ram, 2*E5450@ 3.00GHz ). Here are the results I see: 1. KVM host, stock instalation and fully updated, kernel 3.10.0-1127.10.1 #cd /sys/kernel/debug/x86/ #cat ibrs_enabled pti_enabled retp_enabled 0 1 1 #time yum -y reinstall kernel-3.10.0-1127.el7.x86_64 real 0m50.026s user 0m32.872s sys 0m23.312s 2. KVM guest on the same machine (virt-install --name guest1-rhel7 --memory 2048 --vcpus 2 --disk size=20 --network=bridge:br0 --pxe --os-variant rhel7 <=== copy/paste from https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/ht… ), stock installation and fully updated with absolutely no change towards the defaults including same ibrs_enabled pti_enabled retp_enabled as the host, , kernel 3.10.0-1127.10.1 #time yum -y reinstall kernel-3.10.0-1127.el7.x86_64 real 2m39.644s user 1m54.662s sys 1m32.496s 3. Xen Domu, 3.10.0-1127.8.2.el7.x86_6 ( but results are consistent across all kernels ) # cat ibrs_enabled pti_enabled retp_enabled 0 0 0 # time yum -y reinstall kernel-3.10.0-1127.el7.x86_64 real 5m44.030s user 2m9.931s sys 4m7.771s 4. Dom0, 4.9.215-36.el7.x86_64, , xen 4.12 from centos' repo # time yum -y reinstall kernel-3.10.0-1127.el7.x86_64 real 1m52.417s user 0m45.704s sys 1m32.167s

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very low performance of Xen guests
by Manuel Wolfshant 16 Jun '20

16 Jun '20

Hello For the past months I've been testing upgrading my Xen hosts to CentOS 7 and I face an issue for which I need your help to solve. The testing machines are IBM blades, model H21 and H21XM. Initial tests were performed on the H21 with 16 GB RAM; during the last 6=7 weeks I've been using the H21XM with 64 GB. In all cases the guests were fully updated CentOS 7 -- initially 7.6 ( most recent at the time of the initial tests ), and respectively 7.8 for the tests performed during the last 2 months. As host I used initially CentOS 6 with latest kernel available in the centos virt repo at the time of the tests and CentOS 7 with the latest kernel as well. As xen versions I tested 4.8 and 4.12 ( xl info included below ). The storage for the last tests is a Crucial MX500 but results were similar when using traditional HDD. My problem, in short, is that the guests are extremely slow. For instance , in the most recent tests, a yum install kernel takes cca 1 min on the host and 12-15 (!!!) minutes in the guest, all time being spent in dracut regenerating the initramfs images. I've done rough tests with the storage ( via dd if=/dev/zero of=a_test_file size bs=10M count=1000 ) and the speed was comparable between the hosts and the guests. The version of the kernel in use inside the guest also did not seem to make any difference . OTOH, sysbench ( https://github.com/akopytov/sysbench/ ) as well as p7zip benchmark report for the guests a speed which is between 10% and 50% of the host. Quite obviously, changing the elevator had no influence either. Here is the info which I think that should be relevant for the software versions in use. Feel free to ask for any additional info. [root@t7 ~]# xl info host : t7 release : 4.9.215-36.el7.x86_64 version : #1 SMP Mon Mar 2 11:42:52 UTC 2020 machine : x86_64 nr_cpus : 8 max_cpu_id : 7 nr_nodes : 1 cores_per_socket : 4 threads_per_core : 1 cpu_mhz : 3000.122 hw_caps : bfebfbff:000ce3bd:20100800:00000001:00000000:00000000:00000000:00000000 virt_caps : pv hvm total_memory : 57343 free_memory : 53620 sharing_freed_memory : 0 sharing_used_memory : 0 outstanding_claims : 0 free_cpus : 0 xen_major : 4 xen_minor : 12 xen_extra : .2.39.g3536f8dc xen_version : 4.12.2.39.g3536f8dc xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64 xen_scheduler : credit2 xen_pagesize : 4096 platform_params : virt_start=0xffff800000000000 xen_changeset : xen_commandline : placeholder dom0_mem=1024M,max:1024M cpuinfo com1=115200,8n1 console=com1,tty loglvl=all guest_loglvl=all ucode=-1 cc_compiler : gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-39) cc_compile_by : mockbuild cc_compile_domain : centos.org cc_compile_date : Tue Apr 14 14:22:04 UTC 2020 build_id : 24148a191438467f26a9e16089205544a428f661 xend_config_format : 4 [root@t5 ~]# xl info host : t5 release : 4.9.215-36.el6.x86_64 version : #1 SMP Mon Mar 2 10:30:40 UTC 2020 machine : x86_64 nr_cpus : 8 max_cpu_id : 7 nr_nodes : 1 cores_per_socket : 4 threads_per_core : 1 cpu_mhz : 2000 hw_caps : b7ebfbff:0004e33d:20100800:00000001:00000000:00000000:00000000:00000000 virt_caps : hvm total_memory : 12287 free_memory : 6955 sharing_freed_memory : 0 sharing_used_memory : 0 outstanding_claims : 0 free_cpus : 0 xen_major : 4 xen_minor : 8 xen_extra : .5.86.g8db85532 xen_version : 4.8.5.86.g8db85532 xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64 xen_scheduler : credit xen_pagesize : 4096 platform_params : virt_start=0xffff800000000000 xen_changeset : xen_commandline : dom0_mem=1024M,max:1024M cpuinfo com1=115200,8n1 console=com1,tty loglvl=all guest_loglvl=all cc_compiler : gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-23) cc_compile_by : mockbuild cc_compile_domain : centos.org cc_compile_date : Thu Dec 12 14:34:48 UTC 2019 build_id : da34ae5b90c82137dcbc466cd66322381bc6fd21 xend_config_format : 4 /Note:/ with all other kernels and xen versions that were published for C6 during the last year, the performance was the same, i.e. slow The test VM is exactly the same, copied among servers: [root@t7 ~]# cat /etc/xen/test7_1 builder = "hvm" xen_platform_pci=1 name = "Test7" memory = 2048 maxmem = 4096 vcpus = 2 vif = [ "mac=00:14:5e:d9:df:50,bridge=xenbr0,model=e1000" ] disk = [ "file:/var/lib/xen/images/test7_1,xvda,w" ] sdl = 0 vnc = 1 bootloader = 'xenpvnetboot' #bootloader_args = ['--location', 'http://internal.x.y/mrepo/centos7-x86_64/disc1/'] on_poweroff = 'destroy' on_reboot = 'restart' on_crash = 'restart' #boot="nd" boot="d" pae=1 acpi=1 apic=1 tsc_mode=0 /Notes:/ - the lines past "boot" in the config do not make any difference either, they were added during the last week's tests. - I've tested with 1, 2, 4 and 8 VCPUs . There is no diff for the real life apps. Frankly in this moment I have no idea what else to change or test so .. please help.

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Amazon Machine Image failing because of ec2:RunInstances Not authorized for images: [ami-03c4e540f2256d223]
by Jay Wisniewski 09 Jun '20

09 Jun '20

Hi, Not sure why, but when trying to create an instance the build fails with not being able to access marketplace image. API: ec2:RunInstances Not authorized for images: [ami-03c4e540f2256d223] Currently subscribed to the CENTOS 7 AMI with updates. >From Amazon: This ami-03c4e540f2256d223 may be depreciated by the provider if it is not letting you to launch new instances from it, means it is no longer available. You would need to find the latest AMI version from the marketplace on the page where you begin configuration or I would suggest contact the marketplace provider support directly, unfortunately we do not have insight in those images, only the provider. This way they'll update the below mappings in the CloudFormation template with the relevant AMI for us-west-2 region for you. --- "AWSRegionArch2AMI": { "us-east-1": { "HVM64": "ami-0e683f9e59dd2838c" }, "us-west-2": { "HVM64": "ami-03c4e540f2256d223" }, "us-west-1": { "HVM64": "ami-08eaa393abc9e7ee2" Please advise. Jay Wisniewski Systems Administrator Information Technology

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Centos 8 on AWS
by Thomas Stephen Lee 14 May '20

14 May '20

Hi, Please release CentOS 8 on AWS. reference https://bugs.centos.org/view.php?id=16614#c36929 Also, a query: Is there any cost (money) for releasing on AWS by organizations? thanks --- Lee

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VM migration problems
by isdtor 25 Apr '20

25 Apr '20

I have migrated KVM VMs from a CentOS 6 to a CentOS 7 host. All work fine post-migration, CentOS 3 (don't ask ...), CentOS 6, CentOS 7, Windows. But the CentOS 5 VMs failed. At some point during the boot process, they became unpingable and also inaccessible. I have correlated this to the start of the irqbalance service and was wondering if it is generally considered best practice to turn it off. The VMs in question all have at least 2 vcpus, and the C5 VMs are the odd ones out.

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ANNOUNCE: centos-release-xen to switch to newer xen
by Anthony PERARD 14 Apr '20

14 Apr '20

Greeting, We are about to update the centos-release-xen package to point to a newer version of Xen. That is 4.12 on CentOS 7 but only 4.10 on CentOS 6. As a reminder, you can "pin" your installation to Xen 4.8 by installing centos-release-xen-48 and then removing centos-release-xen. Other available Xen version are: centos-release-xen-48 centos-release-xen-410 centos-release-xen-412 (CentOS 7 only) On CentOS 6, ocaml is too old to build some component of Xen 4.12. There may be other issues. (I'll wait at least two weeks before pushing from testing to the release repo.) Cheers, -- Anthony PERARD

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