- Users - libvirt List Archives

[libvirt-users] OVS / KVM / libvirt / MTU
by Sven Vogel 09 Aug '19

09 Aug '19

Hey there, I hope anyone can bring some light in the following problem. <interface type='bridge'> <source bridge='cloudbr0'/> <mtu size='2000'/> <mac address='02:00:74:76:00:01'/> <model type='virtio'/> <virtualport type='openvswitch'> </virtualport> <vlan trunk='no'> <tag id='2097'/> </vlan><link state='up'/> </interface> we have an base bridge for example and cloudbr0. After we add an mtu to the vm bridge here it seems the base bridge gets the same mtu like the vnet adapter. Is this normal behaviour of libvirt together with OVS? —ovs-vsctl show 5b154321-534d-413e-9761-60476ae06640 Bridge "cloudbr0" Port "cloudbr0" Interface "cloudbr0" type: internal —MTU from the bridge after set an MTU into the XML File (before we had here 9000) mtu : 2000 mtu_request : [] name : "cloudbr0" ofport : 65534 —MTU of the vnet interface mac_in_use : "fe:00:74:76:00:01" mtu : 1450 mtu_request : 1450 name : „vnet2" Thanks for help… __ Sven Vogel Teamlead Platform EWERK RZ GmbH Brühl 24, D-04109 Leipzig P +49 341 42649 - 11 F +49 341 42649 - 18 S.Vogel(a)ewerk.com www.ewerk.com Geschäftsführer: Dr. Erik Wende, Hendrik Schubert, Frank Richter Registergericht: Leipzig HRB 17023 Zertifiziert nach: ISO/IEC 27001:2013 DIN EN ISO 9001:2015 DIN ISO/IEC 20000-1:2011 EWERK-Blog | LinkedIn | Xing | Twitter | Facebook Auskünfte und Angebote per Mail sind freibleibend und unverbindlich. Disclaimer Privacy: Der Inhalt dieser E-Mail (einschließlich etwaiger beigefügter Dateien) ist vertraulich und nur für den Empfänger bestimmt. Sollten Sie nicht der bestimmungsgemäße Empfänger sein, ist Ihnen jegliche Offenlegung, Vervielfältigung, Weitergabe oder Nutzung des Inhalts untersagt. Bitte informieren Sie in diesem Fall unverzüglich den Absender und löschen Sie die E-Mail (einschließlich etwaiger beigefügter Dateien) von Ihrem System. Vielen Dank. The contents of this e-mail (including any attachments) are confidential and may be legally privileged. If you are not the intended recipient of this e-mail, any disclosure, copying, distribution or use of its contents is strictly prohibited, and you should please notify the sender immediately and then delete it (including any attachments) from your system. Thank you.

4 7

[libvirt-users] Vm in state "in shutdown"
by 马昊骢 Ianmalcolm Ma 09 Aug '19

09 Aug '19

Description of problem: libvirt 3.9 on CentOS Linux release 7.4.1708 (kernel 3.10.0-693.21.1.el7.x86_64) on Qemu version 2.10.0 I’m currently facing a strange situation. Sometimes my vm is shown by ‘virsh list’ as in state “in shutdown” but there is no qemu-kvm process linked to it. Libvirt log when “in shutdown” state occur is as follows: “d470c3b284425b9bacb34d3b5f3845fe” is vm’s name, remoteDispatchDomainMemoryStats API is called by ‘collectd’, which is used to collect some vm running states and host information once every 30’s. 2019-07-25 14:23:58.706+0000: 15818: warning : qemuMonitorJSONIOProcessEvent:235 : type: POWERDOWN, vm: d470c3b284425b9bacb34d3b5f3845fe, cost 1.413 secs 2019-07-25 14:23:59.601+0000: 15818: warning : qemuMonitorJSONIOProcessEvent:235 : type: SHUTDOWN, vm: d470c3b284425b9bacb34d3b5f3845fe, cost 1.202 secs 2019-07-25 14:23:59.601+0000: 15818: warning : qemuMonitorJSONIOProcessEvent:235 : type: STOP, vm: d470c3b284425b9bacb34d3b5f3845fe, cost 1.203 secs 2019-07-25 14:23:59.601+0000: 15818: warning : qemuMonitorJSONIOProcessEvent:235 : type: SHUTDOWN, vm: d470c3b284425b9bacb34d3b5f3845fe, cost 1.203 secs 2019-07-25 14:23:59.629+0000: 15818: error : qemuMonitorIORead:597 : Unable to read from monitor: Connection reset by peer 2019-07-25 14:23:59.629+0000: 121081: warning : qemuProcessEventHandler:4840 : vm: d470c3b284425b9bacb34d3b5f3845fe, event: 6 locked 2019-07-25 14:23:59.629+0000: 15822: error : qemuMonitorJSONCommandWithFd:364 : internal error: Missing monitor reply object 2019-07-25 14:24:29.483+0000: 15821: warning : qemuGetProcessInfo:1468 : cannot parse process status data 2019-07-25 14:24:29.829+0000: 15823: warning : qemuDomainObjBeginJobInternal:4391 : Cannot start job (modify, none) for domain d470c3b284425b9bacb34d3b5f3845fe; current job is (query, none) owned by (15822 remoteDispatchDomainMemoryStats, 0 <null>) for (30s, 0s) 2019-07-25 14:24:29.829+0000: 15823: error : qemuDomainObjBeginJobInternal:4403 : Timed out during operation: cannot acquire state change lock (held by remoteDispatchDomainMemoryStats) 2019-07-25 14:24:29.829+0000: 121081: warning : qemuDomainObjBeginJobInternal:4391 : Cannot start job (destroy, none) for domain d470c3b284425b9bacb34d3b5f3845fe; current job is (query, none) owned by (15822 remoteDispatchDomainMemoryStats, 0 <null>) for (30s, 0s) 2019-07-25 14:24:29.829+0000: 121081: error : qemuDomainObjBeginJobInternal:4403 : Timed out during operation: cannot acquire state change lock (held by remoteDispatchDomainMemoryStats) 2019-07-25 14:24:29.829+0000: 121081: warning : qemuProcessEventHandler:4875 : vm: d470c3b284425b9bacb34d3b5f3845fe, event: 6, cost 31.459 secs I’ve tried to find out how did this problem happened. I analyzed the execution process of the job and speculated that the problem occurred as follows: step one: libvirt send command 'system_powerdown' to qemu. step two: libvirt receive qemu monitor close event, and then deal EOF event. step three: remoteDispatchDomainMemoryStats job start on the same vm. step four: work thread dealing stop job is waited on job.cond, the timeout is 30s. It seems that the remoteDispatchDomainMemoryStats job is too slow to let the stop job wait timeout. Then I tried to reproduce this process. The step is as follows: First step: add a sleep on ‘qemuProcessEventHandler' by using pthread_cond_timedwait. So can execute 'virsh dommemstat active’ command at this time interval. Second step: start a vm to test Third step: execute 'virsh shutdown active’ to shutdown the vm Fourth step: execute 'virsh dommemstat active’ when stop job is sleep. Then it works. The test vm state became to 'in shutdown’, and the libvirt log is as follows: “active” is my test vm’s name. 2019-08-05 08:39:57.001+0000: 25889: warning : qemuDomainObjBeginJobInternal:4308 : Starting job: modify (vm=0x7f7bbc145fe0 name=active, current job=none async=none) 2019-08-05 08:39:57.003+0000: 25889: warning : qemuDomainObjEndJob:4522 : Stopping job: modify (async=none vm=0x7f7bbc145fe0 name=active) 2019-08-05 08:39:57.003+0000: 25881: warning : qemuMonitorJSONIOProcessEvent:235 : type: POWERDOWN, vm: active, cost 0.008 secs 2019-08-05 08:39:57.854+0000: 25881: warning : qemuMonitorJSONIOProcessEvent:235 : type: SHUTDOWN, vm: active, cost 1.709 secs 2019-08-05 08:39:57.875+0000: 25881: warning : qemuMonitorJSONIOProcessEvent:235 : type: STOP, vm: active, cost 1.751 secs 2019-08-05 08:39:57.875+0000: 25881: warning : qemuMonitorJSONIOProcessEvent:235 : type: SHUTDOWN, vm: active, cost 1.751 secs 2019-08-05 08:39:57.915+0000: 25881: warning : qemuMonitorIO:756 : Error on monitor <null> 2019-08-05 08:39:57.915+0000: 25881: warning : qemuMonitorIO:777 : Triggering EOF callback 2019-08-05 08:39:57.915+0000: 26915: warning : qemuProcessEventHandler:4822 : usleep 20s 2019-08-05 08:40:01.004+0000: 25886: warning : qemuDomainObjBeginJobInternal:4308 : Starting job: query (vm=0x7f7bbc145fe0 name=active, current job=none async=none) ^@2019-08-05 08:40:17.915+0000: 26915: warning : qemuProcessEventHandler:4845 : vm=0x7f7bbc145fe0, event=6 2019-08-05 08:40:17.915+0000: 26915: warning : qemuProcessEventHandler:4851 : vm: active, event: 6 locked 2019-08-05 08:40:17.915+0000: 26915: warning : qemuDomainObjBeginJobInternal:4308 : Starting job: destroy (vm=0x7f7bbc145fe0 name=active, current job=query async=none) 2019-08-05 08:40:17.915+0000: 26915: warning : qemuDomainObjBeginJobInternal:4344 : Waiting for job (vm=0x7f7bbc145fe0 name=active), job 26915 qemuProcessEventHandler, owned by 25886 remoteDispatchDomainMemoryStats ^@^@^@2019-08-05 08:40:47.915+0000: 26915: warning : qemuDomainObjBeginJobInternal:4405 : Cannot start job (destroy, none) for domain active; current job is (query, none) owned by (25886 remoteDispatchDomainMemoryStats, 0 <null>) for (46s, 0s) 2019-08-05 08:40:47.915+0000: 26915: error : qemuDomainObjBeginJobInternal:4417 : 操作超时：cannot acquire state change lock (held by remoteDispatchDomainMemoryStats) 2019-08-05 08:40:47.915+0000: 26915: warning : qemuProcessEventHandler:4886 : vm: active, event: 6, cost 31.830 secs The threads backtraces is as follows: [Switching to thread 17 (Thread 0x7f12fddf5700 (LWP 32580))] #2 0x00007f12eb26df21 in qemuMonitorSend (mon=mon@entry=0x7f12d0013af0, msg=msg@entry=0x7f12fddf46e0) at qemu/qemu_monitor.c:1075 1075 if (virCondWait(&mon->notify, &mon->parent.lock) < 0) { (gdb) l 1070 PROBE(QEMU_MONITOR_SEND_MSG, 1071 "mon=%p msg=%s fd=%d", 1072 mon, mon->msg->txBuffer, mon->msg->txFD); 1073 1074 while (mon && mon->msg && !mon->msg->finished) { 1075 if (virCondWait(&mon->notify, &mon->parent.lock) < 0) { 1076 virReportError(VIR_ERR_INTERNAL_ERROR, "%s", 1077 _("Unable to wait on monitor condition")); 1078 goto cleanup; 1079 } (gdb) p *msg $2 = {txFD = -1, txBuffer = 0x7f12b8000d50 "{\"execute\":\"qom-list\",\"arguments\":{\"path\":\"/machine/peripheral\"},\"id\":\"libvirt-17\"}\r\n", txOffset = 0, txLength = 85, rxBuffer = 0x0, rxLength = 0, rxObject = 0x0, finished = false, passwordHandler = 0x0, passwordOpaque = 0x0} (gdb) bt #0 pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185 #1 0x00007f130d738316 in virCondWait (c=c@entry=0x7f12d0013b28, m=m@entry=0x7f12d0013b00) at util/virthread.c:154 #2 0x00007f12eb26df21 in qemuMonitorSend (mon=mon@entry=0x7f12d0013af0, msg=msg@entry=0x7f12fddf46e0) at qemu/qemu_monitor.c:1075 #3 0x00007f12eb283b40 in qemuMonitorJSONCommandWithFd ( mon=mon@entry=0x7f12d0013af0, cmd=cmd@entry=0x7f12b80008c0, scm_fd=scm_fd@entry=-1, reply=reply@entry=0x7f12fddf4780) at qemu/qemu_monitor_json.c:355 #4 0x00007f12eb2904b9 in qemuMonitorJSONCommand (reply=0x7f12fddf4780, cmd=0x7f12b80008c0, mon=0x7f12d0013af0) at qemu/qemu_monitor_json.c:385 ... I found that on function ‘qemuMonitorUpdateWatch’, if mon->watch is zero, then event would’t be update. But 'qemuMonitorSend' would still wait on mon->notify. So the remoteDispatchDomainMemoryStats job is blocked, and then the stop job blocked too. 618 static void 619 qemuMonitorUpdateWatch(qemuMonitorPtr mon) 620 { 621 int events = 622 VIR_EVENT_HANDLE_HANGUP | 623 VIR_EVENT_HANDLE_ERROR; 624 625 if (!mon->watch) 626 return; 627 628 if (mon->lastError.code == VIR_ERR_OK) { 629 events |= VIR_EVENT_HANDLE_READABLE; 630 631 if ((mon->msg && mon->msg->txOffset < mon->msg->txLength) && 632 !mon->waitGreeting) 633 events |= VIR_EVENT_HANDLE_WRITABLE; 634 } 635 636 virEventUpdateHandle(mon->watch, events); 637 } I try to fix this bugs by add a judgment before qemuMonitorUpdateWatch, and it seem works. 1046 int 1047 qemuMonitorSend(qemuMonitorPtr mon, 1048 qemuMonitorMessagePtr msg) 1049 { 1050 int ret = -1; 1051 1052 /* Check whether qemu quit unexpectedly */ 1053 if (mon->lastError.code != VIR_ERR_OK) { 1054 VIR_DEBUG("Attempt to send command while error is set %s", 1055 NULLSTR(mon->lastError.message)); 1056 virSetError(&mon->lastError); 1057 return -1; 1058 } 1059 1060 if (!mon->watch) { 1061 VIR_WARN("Attempt to send command while mon->watch is zero"); 1062 virReportError(VIR_ERR_INTERNAL_ERROR, "%s", 1063 _("attempt to send command when the monitor is closing")); 1064 return -1; 1065 } 1066 1067 mon->msg = msg; 1068 qemuMonitorUpdateWatch(mon); 1069 1070 PROBE(QEMU_MONITOR_SEND_MSG, 1071 "mon=%p msg=%s fd=%d", 1072 mon, mon->msg->txBuffer, mon->msg->txFD); 1073 1074 while (mon && mon->msg && !mon->msg->finished) { 1075 if (virCondWait(&mon->notify, &mon->parent.lock) < 0) { 1076 virReportError(VIR_ERR_INTERNAL_ERROR, "%s", 1077 _("Unable to wait on monitor condition")); 1078 goto cleanup; 1079 } 1080 } 1081 1082 if (mon->lastError.code != VIR_ERR_OK) { 1083 VIR_DEBUG("Send command resulted in error %s", 1084 NULLSTR(mon->lastError.message)); 1085 virSetError(&mon->lastError); 1086 goto cleanup; 1087 } 1088 1089 ret = 0; 1090 1091 cleanup: 1092 mon->msg = NULL; 1093 qemuMonitorUpdateWatch(mon); 1094 1095 return ret; 1096 } I’m not really sure that this change will affect other process. Thanks! Ma haocong

2 2

[libvirt-users] libvirt/dnsmasq is not adhering to static DHCP assignments
by Christian Kujau 09 Aug '19

09 Aug '19

This is basically a continuation of an older posting[0] I found, but apparently no solution has been posted. So, I'm trying to setup static DHCP leases with dnsmasq that is being started by libvirtd: ----------------------------------------------------------- $ sudo virsh net-dumpxml --network default <network> [...] <dns enable='no'/> <ip address='192.168.122.1' netmask='255.255.255.0'> <dhcp> <range start='192.168.122.130' end='192.168.122.250'/> <host mac='08:00:27:e2:81:39' name='f30' ip='192.168.56.139'/> ----------------------------------------------------------- And the domain is indeed being started with that hardware address: ----------------------------------------------------------- $ virsh dumpxml --domain f30 | grep -B1 -A3 mac\ a <interface type='bridge'> <mac address='08:00:27:e2:81:39'/> <source bridge='virbr0'/> <target dev='tap0'/> <model type='virtio'/> ----------------------------------------------------------- But for some reason the domain gets a different address assigned, albeit from the correct DHCP pool: ----------------------------------------------------------- $ ssh 192.168.122.233 "ip addr show" [...] 2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 08:00:27:e2:81:39 brd ff:ff:ff:ff:ff:ff inet 192.168.122.233/24 brd 192.168.122.255 scope global dynamic enp1s0 ----------------------------------------------------------- See below for even more details. I've removed the virbr0.status file, restarted the network, still it gets this .233 address instead of the configured .139. Also, I'm not able to add a debug log to the libvirtd/dnsmasq instance, although it should be possible[1], the xmlns:dnsmasq stanza is overwritten as soon as the configuration is saved. Short of a debug (queries) log, strace on the libvirtd/dnsmasq process reveals that the client seems to request this strange IP address: 23002 19:01:59.053558 write(11, "<30>Jul 31 19:01:59 dnsmasq-dhcp[23002]: DHCPREQUEST(virbr0) 192.168.122.233 08:00:27:e2:81:39 ", 95) = 95 23002 19:01:59.054024 write(11, "<30>Jul 31 19:01:59 dnsmasq-dhcp[23002]: DHCPACK(virbr0) 192.168.122.233 08:00:27:e2:81:39 f30", 94) = 94 So I restarted the dhclient process in the domain (a freshly installed Fedora 30), removed all state files with "192.168.122.233" in them, but still the domains gets assigned the .233 instead of the .139 address. The next step would be to disable libvirtd/dnsmasq altogether and run my own dnsmasq instance, but I wanted to avoid that. Any idead on where to look next? Thanks, Christian. [0] https://www.redhat.com/archives/libvirt-users/2017-October/msg00070.html [1] https://libvirt.org/formatnetwork.html#elementsNamespaces # cd /var/lib/libvirt/dnsmasq/ # grep -r . . | fgrep -v \# ./default.conf:strict-order ./default.conf:port=0 ./default.conf:pid-file=/var/run/libvirt/network/default.pid ./default.conf:except-interface=lo ./default.conf:bind-dynamic ./default.conf:interface=virbr0 ./default.conf:dhcp-range=192.168.122.130,192.168.122.250,255.255.255.0 ./default.conf:dhcp-no-override ./default.conf:dhcp-authoritative ./default.conf:dhcp-lease-max=121 ./default.conf:dhcp-hostsfile=/var/lib/libvirt/dnsmasq/default.hostsfile ./default.hostsfile:08:00:27:e2:81:39,192.168.56.139,f30 ./virbr0.status:[ ./virbr0.status: { ./virbr0.status: "ip-address": "192.168.122.233", ./virbr0.status: "mac-address": "08:00:27:e2:81:39", ./virbr0.status: "hostname": "f30", ./virbr0.status: "client-id": "ff:27:e2:81:39:00:04:8c:ad:c4:7d:04:e8:4b:de:93:4b:76:d8:75:82:86:c8", ./virbr0.status: "expiry-time": 1564628519 ./virbr0.status: } ./virbr0.status:] -- BOFH excuse #40: not enough memory, go get system upgrade

2 2

[libvirt-users] Reg: content of disk is not reflecting in host.
by bharath paulraj 07 Aug '19

07 Aug '19

Hi Team, I am doing a small testing and I don't know if my expectation is correct or not. Pardon me if I am ignorant. I created a VM and the VM is running. In the hypervisor I have created ".img" file and attached this .img file to the VM. My expectation is that, if VM is writing files to the attached disk, then it should reflect in the .img file created in the hypervisor. But It is not working as my expectation. Please correct me if my expectation is wrong. Steps: 1. Created disk.img in the hypervisor using the command: dd if=/dev/zero of=disk.img bs=1M count=50; mkfs ext3 -F disk.img 2. Attached the disk to the running VM using the command: virsh attach-disk <Domain-Name> --source disk.img --target vdb --live 3. In the VM, I mounted the disk and created few files. 4. In the hypervisor, I mounted the disk.img to check if the file created in the VM exists in the .img file. >> I am not able to see those files. Regards, Bharath

2 2

[libvirt-users] Dev wanted regarding Ceph and/or libxl related bugs and feature requests
by Julian Sternberg 03 Aug '19

03 Aug '19

Hi there, anybody with ceph api and/or libxl skills able to implement following feature and fix bug requests: https://bugzilla.redhat.com/show_bug.cgi?id=1729408 https://bugzilla.redhat.com/show_bug.cgi?id=1731159 https://bugzilla.redhat.com/show_bug.cgi?id=1732306

1 0

[libvirt-users] Detach disk from VM - virsh (working) vs. PHP (not working)
by Jan Horak 03 Aug '19

03 Aug '19

Hi all, i created a script in PHP for create a virtual server with two QCOW2 discs … one is our system for installation and second is target system. After successfully instalation (create a blank Debian system, prepare all files and grub partitions) i need a restart virtual without a installation disk. If i use Virsh: detach-disk --domain debian-test2 --persistent --target vda reset debian-test2 everything works well. If i use a PHP, there is „complicated“ way and „simple“ way: 1, complicated: libvirt_domain_destroy($domain); libvirt_domain_undefine($domain); $xml = domain_create_xml($name,$uuid,$memory,$cpu,$vnc,$mac); $domain = libvirt_domain_define_xml($server->conn, $xml); libvirt_domain_disk_add($domain, "/users/".$name.".img", "vdb", "virtio", "qcow2", NULL); libvirt_domain_create($domain); (or instead libvirt_domain_disk_add i can define disk directly in XML) But in this case, the server will not boot (GRUB error) 2, simple: libvirt_domain_disk_remove($domain,“vda“); libvirt_domain_reboot($domain); The problem of this solution is thats not working. The remove disk is failing with error „Unable attach disk“ - i looks to source code, and yes, there is a mystake with „attach“/„detach“, but main problem i see in log from libvirt: Aug 1 02:57:05 ry libvirtd[19051]: missing source information for device vda I try to put source detail to xml in source of PHP module libvirt-domain.c: 822 if (asprintf(&newXml, 823 " <disk type='file' device='disk'>\n" 824 " <target dev='%s'/>\n" 825 " </disk>", dev) < 0) { 826 set_error("Out of memory" TSRMLS_CC); 827 goto error; 828 } but my attempts was unsuccesfull (i’m not C programmer). Questions: A, why complicated way is not working and system dont want boot (GRUB error) if virsh works fine B, why libvirt_domain_disk_remove is not work ? I use libvirt and libvirt-php latest from git. Thank you, Jan

4 5

[libvirt-users] Researching why different cache modes result in 'some' guest filesystem corruption..
by vincent＠cojot.name 02 Aug '19

02 Aug '19

Hi All, I've been chasing down an issue in recent weeks (my own lab, so no prod here) and I'm reaching out in case someone might have some guidance to share. I'm running fairly large VMs (RHOSP underclouds - 8vcpu, 32gb ram, about 200gb single disk as a growable qcow2) on some RHEL7.6 hypervisors (kernel 3.10.0-927.2x.y, libvirt 4.5.0, qemu-kvm-1.5.3) on top of SSD/NVMe drives with various filesystems (vxfs, zfs, etc..) and using ECC RAM. The issue can be described as follows: - the guest VMs work fine for a while (days, weeks) but after a kernel update (z-stream) comes in, I am often greeted by the following message immediately after rebooting (or attempting to reboot into the new kernel): "error: not a correct xfs inode" - booting the previous kernel works fine and re-generating the initramfs for the new kernel (from the n-1 kernel) does not solve anything. - if booted from an ISO, xfs_repair does not find errors. - on ext4, there seems to be some kind of corruption there too. I'm building the initial guest image qcow2 for those guest VMs this way: 1) start with a rhel-guest image (currently rhel-server-7.6-update-5-x86_64-kvm.qcow2) 2) convert to LVM by doing this: qemu-img create -f qcow2 -o preallocation=metadata,cluster_size=1048576,lazy_refcounts=off final_guest.qcow2 512G virt-format -a final_guest.qcow2 --partition=mbr --lvm=/dev/rootdg/lv_root --filesystem=xfs guestfish --ro -a rhel_guest.qcow2 -m /dev/sda1 -- tar-out / - | \ guestfish --rw -a final_guest.qcow2 -m /dev/rootdg/lv_root -- tar-in - / 3) use "final_guest.qcow2" as the basis for my guests with LVM. After chasing down this issue some more and attempting various things (build the image on Fedora29, build a real XFS filesystem inside a VM and use the generated qcow2 as a basis instead of virt-format).. ..I've noticed that the SATA disk of each of those guests were using 'directsync' (instead of 'Hypervisor Default'). As soon as I switched to 'None', the XFS issues disappeared and I've now applied several consecutive kernel updates without issues. Also, 'directsync' or 'writethrough', while providing decent performance, both exhibited the XFS 'corruption' behaviour.. Only 'none' seem to have solved that. I've read the docs but I thought it was OK to use those modes (UPS, Battery-Backed RAID, etc..) Does anyone have any idea what's going on or what I may be doing wrong? Thanks for reading, Vincent

2 1

[libvirt-users] Why librbd disallow VM live migration if the disk cache mode is not none or directsync
by Ming-Hung Tsai 01 Aug '19

01 Aug '19

I'm curious that why librbd sets this limitation? The rule first appeared in librbd.git commit d57485f73ab. Theoretically, a write-through cache is also safe for VM migration, if the cache implementation guarantees that cache invalidation and disk write are synchronous operations. For example, I'm using Ceph RBD images as VM storage backend. The Ceph librbd supports synchronous write-through cache, by setting rbd_cache_max_dirty to zero, and setting rbd_cache_block_writes_upfront to true, thus it would be safe for VM migration. Is that true? Any suggestion would be appreciated. Thanks. Ming-Hung Tsai

2 3

[libvirt-users] Libvirt Virtualization Problem
by 王金磊 30 Jul '19

30 Jul '19

Dear Sir/Madam: I use virt-manager to create a new virtual machine(it's name is generic), then I edit generic to set it's cpu_mode as 'host-model', and I start it, but when dumpxml generic, it's cpu_mode is changed as 'custom'. I want to know that why it is? And what's the principle of dumpxml? Thanks! A user of libvirt

2 1

[libvirt-users] virsh command to list CPU,Memory and Storage
by Kaushal Shriyan 30 Jul '19

30 Jul '19

Hi, Is there a way to find out total CPU's, Memory and Storage using virsh command? For example virsh list --all list out all VM's 11 dockerregistry01 running 12 gitlab running Any help will be highly appreciated. Thanks in Advance. Best Regards, Kaushal

3 2