Suggested hack works, seems that libvirt devs does not remove block limitation as they count this feature as experimental, or forgot about it.
On Tue, Apr 3, 2012 at 12:55 PM, Andrey Korolyov <and...@xdel.ru> wrote: > At least, elements under <iotune> block applies to rbd and you can > test it by running fio, for example. I have suggested by reading > libvirt code that blkdeviotune call can be applied to pseudo-devices, > there are no counterpoints in code that shows different behavior for > iotune and blkdeviotune calls at all. Seems that libvirt folks did not > pushed workaround for sheepdog/ceph at all. I`ll try a dirty hack in > this code snippet (somehow, I overlooked such idea that there is no > non-block workaround) and report soon. > > On Tue, Apr 3, 2012 at 12:45 PM, Wido den Hollander <w...@widodh.nl> wrote: >> Op 3-4-2012 10:28, Andrey Korolyov schreef: >> >>> But I am able to set static limits in the config for rbd :) All I want >>> is a change on-the-fly. >>> >>> It is NOT cgroups mechanism, but completely qemu-driven. >> >> >> Are you sure about that? >> http://libvirt.org/formatdomain.html#elementsBlockTuning >> >> Browsing through the source code I found that this is indeed related to >> libvirt. >> >> In the Qemu driver: >> >> if (disk->type != VIR_DOMAIN_DISK_TYPE_BLOCK && >> disk->type != VIR_DOMAIN_DISK_TYPE_FILE) >> goto cleanup; >> ... >> ... >> cleanup: >> if (!ret) { >> qemuReportError(VIR_ERR_INVALID_ARG, >> "%s", _("No device found for specified path")); >> } >> >> >> RBD devices are however of the type: VIR_DOMAIN_DISK_TYPE_NETWORK >> >> That's why you get this error, it's assuming the device you want to set the >> limits on is a block device or a regular file. >> >> Wido >> >> >>> >>> On Tue, Apr 3, 2012 at 12:21 PM, Wido den Hollander<w...@widodh.nl> >>> wrote: >>>> >>>> Hi, >>>> >>>> Op 3-4-2012 10:02, Andrey Korolyov schreef: >>>> >>>>> Hi, >>>>> >>>>> # virsh blkdeviotune Test vdb --write_iops_sec 50 //file block device >>>>> >>>>> # virsh blkdeviotune Test vda --write_iops_sec 50 //rbd block device >>>>> error: Unable to change block I/O throttle >>>>> error: invalid argument: No device found for specified path >>>> >>>> >>>> >>>> That is correct. As far as I know iotune uses the underlying cgroups from >>>> the OS. >>>> >>>> RBD devices (when using Qemu) are not block devices which can be managed >>>> by >>>> cgroups. That's why it's not working and you get the error that the >>>> device >>>> can't be found. >>>> >>>> There is however somebody working on DiskIoThrottling inside Qemu: >>>> http://wiki.qemu.org/Features/DiskIOLimits >>>> >>>> That would work with RBD (he even names Ceph :) ) >>>> >>>> Wido >>>> >>>>> >>>>> 2012-04-03 07:38:49.170+0000: 30171: debug : >>>>> virDomainSetBlockIoTune:18317 : dom=0x1114590, (VM: name=Test, >>>>> uuid=8c27bf32-82dc-315a-d0ba-4653b1b3d595), disk=vda, >>>>> params=0x1114600, nparams=1, flags=0 >>>>> 2012-04-03 07:38:49.170+0000: 30169: debug : >>>>> virEventPollMakePollFDs:383 : Prepare n=8 w=11, f=16 e=1 d=0 >>>>> 2012-04-03 07:38:49.170+0000: 30169: debug : >>>>> virEventPollCalculateTimeout:325 : Calculate expiry of 4 timers >>>>> 2012-04-03 07:38:49.170+0000: 30169: debug : >>>>> virEventPollCalculateTimeout:331 : Got a timeout scheduled for >>>>> 1333438734170 >>>>> 2012-04-03 07:38:49.170+0000: 30171: error : qemuDiskPathToAlias:11338 >>>>> : invalid argument: No device found for specified path >>>>> 2012-04-03 07:38:49.170+0000: 30171: debug : virDomainFree:2313 : >>>>> dom=0x1114590, (VM: name=Test, >>>>> uuid=8c27bf32-82dc-315a-d0ba-4653b1b3d595) >>>>> 2012-04-03 07:38:49.170+0000: 30171: debug : virUnrefDomain:276 : >>>>> unref domain 0x1114590 Test 1 >>>>> 2012-04-03 07:38:49.170+0000: 30171: debug : virReleaseDomain:238 : >>>>> release domain 0x1114590 Test 8c27bf32-82dc-315a-d0ba-4653b1b3d595 >>>>> 2012-04-03 07:38:49.170+0000: 30169: debug : >>>>> virEventPollCalculateTimeout:351 : Timeout at 1333438734170 due in >>>>> 5000 ms >>>>> 2012-04-03 07:38:49.170+0000: 30169: debug : virEventPollRunOnce:619 : >>>>> EVENT_POLL_RUN: nhandles=9 imeout=5000 >>>>> 2012-04-03 07:38:49.170+0000: 30171: debug : virReleaseDomain:246 : >>>>> unref connection 0x1177b10 2 >>>>> >>>>> libvir 0.9.10, json-escape patch applied, but seems that this problem >>>>> related to another incorrect path handle. >>>>> >>>>> I`m in doubt if it belongs to libvirt ml or here. >>>>> -- >>>>> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >>>>> the body of a message to majord...@vger.kernel.org >>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>> >>>> >>>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >>> the body of a message to majord...@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
