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 <wido@xxxxxxxxx> 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<wido@xxxxxxxxx> >> 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 majordomo@xxxxxxxxxxxxxxx >>>> 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 majordomo@xxxxxxxxxxxxxxx >> 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 majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
