# [OmniOS-discuss] horrible disk performance under KVM

ashley willis ashleywillis76 at gmail.com
Fri Sep 13 23:38:18 UTC 2013

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    I decided to run the mongorestore tool from the bare metal OmniOS to
    the mongo server running in KVM CentOS, and it is running much quicker
    -- 50% in 12m52s (and the CPU and memory for mongorestore is only
    0.3%). MongoDB is not using much CPU in the VM, either. Total import
    time this way is 32m12.235s -- still much slower than just bare metal,
    but not insanely slow like before (the NFS->NFS all within the OmniOS
    VM was 92m48s). Giving the VM 6 cores and 14GB of ram (instead of 2
    and 2) gave somewhat better performance: 27m18.305s. Going back to
    if=ide, 35m51.575s, so if=virtio does help here some.

    Is there anything else that can be done to improve disk I/O in a VM,
    short of giving the VM an entire physical disk?

    -ashley

    On Fri, Sep 13, 2013 at 4:58 PM, ashley willis <ashleywillis76 at gmail.com> wrote:
    > So, a CentOS 6.4 VM is still horrible with virtio -- it's loaded 2% of
    > the database in 6 minutes onto a 30g ext4 partition.
    >
    > On Fri, Sep 13, 2013 at 4:24 PM, ashley willis <ashleywillis76 at gmail.com> wrote:
    >> that works for booting centos 6.4, but not for booting omnios -- grub
    >> comes up but it keeps looping back to the grub menu. granted, i don't
    >> really need to boot omnios in kvm. i had horrible performance in
    >> centos as well, so i will try this.
    >>
    >> for comparison to my home machine, on a work server i loaded that same
    >> dataset in 4m10s (xeon 2*6 cores, 60GB ram, 12 600GB 10k SAS drives in
    >> raid10) reading from disks in a different box.
    >>
    >> -ashley
    >>
    >> On Fri, Sep 13, 2013 at 3:50 PM, Narayan Desai <narayan.desai at gmail.com> wrote:
    >>> Depending on the availability of the guest-side drivers, it should be a lot
    >>> faster to use virtio, both for disk and net.
    >>>
    >>> Does anyone know if virtio support ships now in OmniOS? I know there have
    >>> been some drivers floating around for a while now, but haven't tried them.
    >>>  -nld
    >>>
    >>>
    >>> On Fri, Sep 13, 2013 at 1:45 PM, ashley willis <ashleywillis76 at gmail.com>
    >>> wrote:
    >>>>
    >>>> I have 14GB dump of a MongoDB database that took 10 minutes to restore
    >>>> on bare metal OmniOS -- I'm fine with this (system is an 8-core AMD
    >>>> FX-8150, 32GB ram, pair of 500GB WD 'blue" drives mirrored, 90GB ssd
    >>>> cache -- all desktop-grade).
    >>>>
    >>>> Running OmniOS under KVM on this box, the same operation took 246
    >>>> minutes with the dump available over an NFS share from the bare metal
    >>>> system (given 2 cores, 2GB ram, and a 30GB zvol).
    >>>>
    >>>> Under the same KVM instance, I decided to see the performance reading
    >>>> the dump from NFS and having the MongoDB data directory on this same
    >>>> NFS share, and it's on track to finish in under 60 minutes (half-way
    >>>> done). That's more than 4 times faster.
    >>>>
    >>>> What gives?
    >>>>
    >>>> /usr/bin/qemu-system-x86_64 -name OmniOS_Text_r151006p.iso -enable-kvm
    >>>> -vnc 0.0.0.0:15 -smp 2 -m 2048 -no-hpet -localtime -drive
    >>>> file=/dev/zvol/rdsk/rpool/omnios,if=ide,index=0 -net
    >>>> nic,vlan=0,name=net0,model=e1000,macaddr=2:8:20:e:15:33 -net
    >>>> vnic,vlan=0,name=net0,ifname=vnic10,macaddr=2:8:20:e:15:33 -vga std
    >>>> -daemonize
    >>>>
    >>>> -ashley
    >>>> _______________________________________________
    >>>> OmniOS-discuss mailing list
    >>>> OmniOS-discuss at lists.omniti.com
    >>>> http://lists.omniti.com/mailman/listinfo/omnios-discuss
    >>>
    >>>

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