[Gluster-devel] [Gluster-users] VMs blocked for more than 120 seconds

Mon May 13 07:34:07 UTC 2019

as per
https://helpful.knobs-dials.com/index.php/INFO:_task_blocked_for_more_than_120_seconds.
,
the informational warning could be suppressed with :

"echo 0 > /proc/sys/kernel/hung_task_timeout_secs"

Moreover, as per their website : "*This message is not an error*.
It is an indication that a program has had to wait for a very long time,
and what it was doing. "
More reference:
https://serverfault.com/questions/405210/can-high-load-cause-server-hang-and-error-blocked-for-more-than-120-seconds

Regards,
Andrei

On Mon, May 13, 2019 at 7:32 AM Martin Toth <snowmailer at gmail.com> wrote:

> Cache in qemu is none. That should be correct. This is full command :
>
> /usr/bin/qemu-system-x86_64 -name one-312 -S -machine
> pc-i440fx-xenial,accel=kvm,usb=off -m 4096 -realtime mlock=off -smp
> 4,sockets=4,cores=1,threads=1 -uuid e95a774e-a594-4e98-b141-9f30a3f848c1
> -no-user-config -nodefaults -chardev
> socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-one-312/monitor.sock,server,nowait
> -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime
> -no-shutdown -boot order=c,menu=on,splash-time=3000,strict=on -device
> piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2
>
> -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x4
> -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x5
> -drive file=/var/lib/one//datastores/116/312/*disk.0*
> ,format=raw,if=none,id=drive-virtio-disk1,cache=none
> -device
> virtio-blk-pci,scsi=off,bus=pci.0,addr=0x6,drive=drive-virtio-disk1,id=virtio-disk1
> -drive file=gluster://localhost:24007/imagestore/
> *7b64d6757acc47a39503f68731f89b8e*
> ,format=qcow2,if=none,id=drive-scsi0-0-0-0,cache=none
> -device
> scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0
> -drive file=/var/lib/one//datastores/116/312/*disk.1*
> ,format=raw,if=none,id=drive-ide0-0-0,readonly=on
> -device ide-cd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0
>
> -netdev tap,fd=26,id=hostnet0
> -device e1000,netdev=hostnet0,id=net0,mac=02:00:5c:f0:e4:39,bus=pci.0,addr=0x3
> -chardev pty,id=charserial0 -device
> isa-serial,chardev=charserial0,id=serial0
> -chardev socket,id=charchannel0,path=/var/lib/libvirt/qemu/channel/target/domain-one-312/org.qemu.guest_agent.0,server,nowait
> -device
> virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0
> -vnc 0.0.0.0:312,password -device cirrus-vga,id=video0,bus=pci.0,addr=0x2
> -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x7 -msg timestamp=on
>
> I’ve highlighted disks. First is VM context disk - Fuse used, second is
> SDA (OS is installed here) - libgfapi used, third is SWAP - Fuse used.
>
> Krutika,
> I will start profiling on Gluster Volumes and wait for next VM to fail.
> Than I will attach/send profiling info after some VM will be failed. I
> suppose this is correct profiling strategy.
>
> Thanks,
> BR!
> Martin
>
> On 13 May 2019, at 09:21, Krutika Dhananjay <kdhananj at redhat.com> wrote:
>
> Also, what's the caching policy that qemu is using on the affected vms?
> Is it cache=none? Or something else? You can get this information in the
> command line of qemu-kvm process corresponding to your vm in the ps output.
>
> -Krutika
>
> On Mon, May 13, 2019 at 12:49 PM Krutika Dhananjay <kdhananj at redhat.com>
> wrote:
>
>> What version of gluster are you using?
>> Also, can you capture and share volume-profile output for a run where you
>> manage to recreate this issue?
>>
>> https://docs.gluster.org/en/v3/Administrator%20Guide/Monitoring%20Workload/#running-glusterfs-volume-profile-command
>> Let me know if you have any questions.
>>
>> -Krutika
>>
>> On Mon, May 13, 2019 at 12:34 PM Martin Toth <snowmailer at gmail.com>
>> wrote:
>>
>>> Hi,
>>>
>>> there is no healing operation, not peer disconnects, no readonly
>>> filesystem. Yes, storage is slow and unavailable for 120 seconds, but why,
>>> its SSD with 10G, performance is good.
>>>
>>> > you'd have it's log on qemu's standard output,
>>>
>>> If you mean /var/log/libvirt/qemu/vm.log there is nothing. I am looking
>>> for problem for more than month, tried everything. Can’t find anything. Any
>>> more clues or leads?
>>>
>>> BR,
>>> Martin
>>>
>>> > On 13 May 2019, at 08:55, lemonnierk at ulrar.net wrote:
>>> >
>>> > On Mon, May 13, 2019 at 08:47:45AM +0200, Martin Toth wrote:
>>> >> Hi all,
>>> >
>>> > Hi
>>> >
>>> >>
>>> >> I am running replica 3 on SSDs with 10G networking, everything works
>>> OK but VMs stored in Gluster volume occasionally freeze with “Task XY
>>> blocked for more than 120 seconds”.
>>> >> Only solution is to poweroff (hard) VM and than boot it up again. I
>>> am unable to SSH and also login with console, its stuck probably on some
>>> disk operation. No error/warning logs or messages are store in VMs logs.
>>> >>
>>> >
>>> > As far as I know this should be unrelated, I get this during heals
>>> > without any freezes, it just means the storage is slow I think.
>>> >
>>> >> KVM/Libvirt(qemu) using libgfapi and fuse mount to access VM disks on
>>> replica volume. Can someone advice  how to debug this problem or what can
>>> cause these issues?
>>> >> It’s really annoying, I’ve tried to google everything but nothing
>>> came up. I’ve tried changing virtio-scsi-pci to virtio-blk-pci disk
>>> drivers, but its not related.
>>> >>
>>> >
>>> > Any chance your gluster goes readonly ? Have you checked your gluster
>>> > logs to see if maybe they lose each other some times ?
>>> > /var/log/glusterfs
>>> >
>>> > For libgfapi accesses you'd have it's log on qemu's standard output,
>>> > that might contain the actual error at the time of the freez.
>>> > _______________________________________________
>>> > Gluster-users mailing list
>>> > Gluster-users at gluster.org
>>> > https://lists.gluster.org/mailman/listinfo/gluster-users
>>>
>>> _______________________________________________
>>> Gluster-users mailing list
>>> Gluster-users at gluster.org
>>> https://lists.gluster.org/mailman/listinfo/gluster-users
>>
>>
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