[ovirt-users] Ovirt with bad IO performance

Yaniv Kaul ykaul at redhat.com
Mon Sep 5 15:01:43 UTC 2016 

On Mon, Sep 5, 2016 at 1:45 PM, Gabriel Ozaki <gabriel.ozaki at kemi.com.br>
wrote:

> Hi Yaniv and Sandro
>
> The disk is in the same machine then ovirt-engine
>

I'm looking back at your results, and something is terribly wrong there:
For example, sysbench:

Host result:            2.9843Mb/sec
Ovirt result:           1.1561Mb/sec
Xenserver result:   2.9006Mb/sec

This is slower than a USB1 disk on key performance. I don't know what to
make of it, but it's completely bogus. Even plain QEMU can get better
results than this.
And the 2nd benchmark:


**The novabench test:*
Ovirt result:          79Mb/s
Xenserver result:  101Mb/s

This is better, but still very slow. If I translate it to MB/s, it's
~10-12MBs - still very very slow.
If, however, this is MB/sec, then this makes sense - and is probably as
much as you can get from a single spindle.
The difference between XenServer and oVirt are more likely have to do with
caching than anything else. I don't know what the caching settings of
XenServer - can you ensure no caching ('direct IO') is used?



> Thanks
>
>
>
>
>
> 2016-09-02 15:31 GMT-03:00 Yaniv Kaul <ykaul at redhat.com>:
>
>>
>>
>> On Fri, Sep 2, 2016 at 6:11 PM, Gabriel Ozaki <gabriel.ozaki at kemi.com.br>
>> wrote:
>>
>>> Hi Yaniv
>>>
>>> Sorry guys, i don't explain well on my first mail, i notice a bad IO
>>> performance on *disk* benchmarks, the network are working really fine
>>>
>>
>> But where is the disk? If it's across the network, then network is
>> involved and is certainly a bottleneck.
>> Y.
>>
>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> 2016-09-02 12:04 GMT-03:00 Yaniv Kaul <ykaul at redhat.com>:
>>>
>>>> On Fri, Sep 2, 2016 at 5:33 PM, Gabriel Ozaki <
>>>> gabriel.ozaki at kemi.com.br> wrote:
>>>>
>>>>> Hi Nir, thanks for the answer
>>>>>
>>>>>
>>>>> *The nfs server is in the host?*
>>>>> Yes, i choose NFS to use as storage on ovirt host
>>>>>
>>>>> *- Is this 2.9GiB/s or 2.9 MiB/s?*
>>>>> Is MiB/s, i put the full test on paste bin
>>>>> centos guest on ovirt:
>>>>> http://pastebin.com/d48qfvuf
>>>>>
>>>>> centos guest on xenserver:
>>>>> http://pastebin.com/gqN3du29
>>>>>
>>>>> how the test works:
>>>>> https://www.howtoforge.com/how-to-benchmark-your-system-cpu-
>>>>> file-io-mysql-with-sysbench
>>>>>
>>>>> *- Are you testing using NFS in all versions?*
>>>>> i am using the v3 version
>>>>>
>>>>> *- What is the disk format?*
>>>>> partion size format
>>>>> /    20Gb xfs
>>>>> swap 2 Gb xfs
>>>>> /dados rest of disk xfs   (note, this is the partition where i save
>>>>> the ISOs,exports and VM disks)
>>>>>
>>>>>
>>>>> *- How do you test io on the host?*
>>>>> I do a clean install of centos and do the test before i install the
>>>>> ovirt
>>>>> the test:
>>>>> http://pastebin.com/7RKU7778
>>>>>
>>>>> *- What kind of nic is used? (1G, 10G?)*
>>>>> Is only a 100mbps :(
>>>>>
>>>>
>>>> 100Mbps will not get you more than several MB/s. 11MB/s on a very
>>>> bright day...
>>>>
>>>>>
>>>>> *We need much more details to understand what do you test here.*
>>>>> I have problems to upload the benchmark test on orvirt to novabench
>>>>> site, so here is the screenshot(i make a mistake on the last email i get
>>>>> the wrong value), is 86 Mb/s:
>>>>>
>>>>
>>>> Which is not possible on the wire. Unless it's VM to VM? And the
>>>> storage is local, which means it's the bandwidth of the physical disk
>>>> itself?
>>>> Y.
>>>>
>>>>
>>>>
>>>>>
>>>>> ​
>>>>> And the novabench on xenserver:
>>>>> https://novabench.com/compare.php?id=ba8dd628e4042dfc1f3d396
>>>>> 70b164ab11061671
>>>>>
>>>>> *- For Xenserver - detailed description of the vm and the storage
>>>>> configuration?*
>>>>> The host is the same(i install xenserver, do the tests before i
>>>>> install centos), the VM i use the same configuration of ovirt, 2 cores, 4
>>>>> Gb of ram and 60 Gb disk(in the default xenserver SR)
>>>>>
>>>>> *- For ovirt, can you share the vm command line, available in
>>>>> /var/log/libvirt/qemu/vmname.**log?*
>>>>> 2016-09-01 12:50:28.268+0000: starting up libvirt version: 1.2.17,
>>>>> package: 13.el7_2.5 (CentOS BuildSystem <http://bugs.centos.org>,
>>>>> 2016-06-23-14:23:27, worker1.bsys.centos.org), qemu version: 2.3.0
>>>>> (qemu-kvm-ev-2.3.0-31.el7.16.1)
>>>>> LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
>>>>> QEMU_AUDIO_DRV=none /usr/libexec/qemu-kvm -name vmcentos -S -machine
>>>>> pc-i440fx-rhel7.2.0,accel=kvm,usb=off -cpu Haswell-noTSX -m
>>>>> size=4194304k,slots=16,maxmem=4294967296k -realtime mlock=off -smp
>>>>> 2,maxcpus=16,sockets=16,cores=1,threads=1 -numa
>>>>> node,nodeid=0,cpus=0-1,mem=4096 -uuid 21872e4b-7699-4502-b1ef-2c058eff1c3c
>>>>> -smbios type=1,manufacturer=oVirt,product=oVirt
>>>>> Node,version=7-2.1511.el7.centos.2.10,serial=03AA02FC-0414-0
>>>>> 5F8-D906-710700080009,uuid=21872e4b-7699-4502-b1ef-2c058eff1c3c
>>>>> -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/va
>>>>> r/lib/libvirt/qemu/domain-vmcentos/monitor.sock,server,nowait -mon
>>>>> chardev=charmonitor,id=monitor,mode=control -rtc
>>>>> base=2016-09-01T09:50:28,driftfix=slew -global
>>>>> kvm-pit.lost_tick_policy=discard -no-hpet -no-shutdown -boot
>>>>> strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2
>>>>> -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x3 -device
>>>>> virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x4
>>>>> -drive file=/rhev/data-center/mnt/ovirt.kemi.intranet:_dados_iso/52
>>>>> ee9f87-9d38-48ec-8003-193262f81994/images/11111111-1111-1111
>>>>> -1111-111111111111/CentOS-7-x86_64-NetInstall-1511.iso,if=no
>>>>> ne,id=drive-ide0-1-0,readonly=on,format=raw -device
>>>>> ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0,bootindex=2
>>>>> -drive file=/rhev/data-center/00000001-0001-0001-0001-0000000002bb/
>>>>> 4ccdd1f3-ee79-4425-b6ed-5774643003fa/images/2ecfcf18-ae84-4e
>>>>> 73-922f-28b9cda9e6e1/800f05bf-23f7-4c9d-8c1d-b2503592875f,if
>>>>> =none,id=drive-virtio-disk0,format=raw,serial=2ecfcf18-ae84-
>>>>> 4e73-922f-28b9cda9e6e1,cache=none,werror=stop,rerror=stop,aio=threads
>>>>> -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x6,drive=drive-virti
>>>>> o-disk0,id=virtio-disk0,bootindex=1 -chardev
>>>>> socket,id=charchannel0,path=/var/lib/libvirt/qemu/channels/2
>>>>> 1872e4b-7699-4502-b1ef-2c058eff1c3c.com.redhat.rhevm.vdsm,server,nowait
>>>>> -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel
>>>>> 0,id=channel0,name=com.redhat.rhevm.vdsm -chardev
>>>>> socket,id=charchannel1,path=/var/lib/libvirt/qemu/channels/2
>>>>> 1872e4b-7699-4502-b1ef-2c058eff1c3c.org.qemu.guest_agent.0,server,nowait
>>>>> -device virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel
>>>>> 1,id=channel1,name=org.qemu.guest_agent.0 -device
>>>>> usb-tablet,id=input0 -vnc 192.168.0.189:0,password -k pt-br -device
>>>>> VGA,id=video0,vgamem_mb=16,bus=pci.0,addr=0x2 -device
>>>>> virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5 -msg timestamp=on
>>>>> 2016-09-01T12:50:28.307173Z qemu-kvm: warning: CPU(s) not present in
>>>>> any NUMA nodes: 2 3 4 5 6 7 8 9 10 11 12 13 14 15
>>>>> 2016-09-01T12:50:28.307371Z qemu-kvm: warning: All CPU(s) up to
>>>>> maxcpus should be described in NUMA config
>>>>> qemu: terminating on signal 15 from pid 1
>>>>> 2016-09-01 19:13:47.899+0000: shutting down
>>>>>
>>>>>
>>>>> Thanks
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> 2016-09-02 11:05 GMT-03:00 Nir Soffer <nsoffer at redhat.com>:
>>>>>
>>>>>> On Fri, Sep 2, 2016 at 4:44 PM, Gabriel Ozaki <
>>>>>> gabriel.ozaki at kemi.com.br> wrote:
>>>>>>
>>>>>>> Hi
>>>>>>> i am trying Ovirt 4.0 and i am getting some strange results when
>>>>>>> comparing with Xenserver
>>>>>>>
>>>>>>> **The host machine*
>>>>>>> Intel Core i5-4440 3.10GHz running at 3093 MHz
>>>>>>> 8 Gb of RAM (1x8)
>>>>>>> 500 Gb of Disk (seagate st500dm002 7200rpm)
>>>>>>> CentOS 7 (netinstall for the most updated and stable packages)
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> **How i am testing:*
>>>>>>> I choose two benchmark tools, sysbench(epel-repo on centos) and
>>>>>>> novabench(for windows guest, https://novabench.com ), then i make a
>>>>>>> clean install of xenserver and create two guests(CentOS and Windows 7 SP1)
>>>>>>>
>>>>>>>
>>>>>>> **The Guest specs*
>>>>>>> 2 cores
>>>>>>> 4 Gb of RAM
>>>>>>> 60 Gb of disk (using virtIO in a NFS storage)
>>>>>>>
>>>>>>
>>>>>> The nfs server is in the host?
>>>>>>
>>>>>>
>>>>>>> Important note: only the testing guest are up on benchmark and i
>>>>>>> have installed the drivers in guest
>>>>>>>
>>>>>>>
>>>>>>> **The Sysbench disk test(creates 10Gb of data and do the bench):*
>>>>>>> # sysbench --test=fileio --file-total-size=10G prepare
>>>>>>> # sysbench --test=fileio --file-total-size=10G
>>>>>>> --file-test-mode=rndrw --init-rng=on --max-time=300 --max-requests=0 run
>>>>>>>
>>>>>>> Host result:            2.9843Mb/sec
>>>>>>> Ovirt result:           1.1561Mb/sec
>>>>>>> Xenserver result:   2.9006Mb/sec
>>>>>>>
>>>>>>
>>>>>> - Is this 2.9GiB/s or 2.9 MiB/s?
>>>>>> - Are you testing using NFS in all versions?
>>>>>> - What is the disk format?
>>>>>> - How do you test io on the host?
>>>>>> - What kind of nic is used? (1G, 10G?)
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> **The novabench test:*
>>>>>>> Ovirt result:          79Mb/s
>>>>>>> Xenserver result:  101Mb/s
>>>>>>>
>>>>>>
>>>>>> We need much more details to understand what do you test here.
>>>>>>
>>>>>> - For ovirt, can you share the vm command line, available in
>>>>>> /var/log/libvirt/qemu/vmname.log?
>>>>>> - For Xenserver - detailed description of the vm and the storage
>>>>>> configuration?
>>>>>>
>>>>>> Nir
>>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Users mailing list
>>>>> Users at ovirt.org
>>>>> http://lists.ovirt.org/mailman/listinfo/users
>>>>>
>>>>>
>>>>
>>>
>>
>
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