Re: [Qemu-block] [RFC v6] RBD: Add support readv,writev for rbd

[Jaze Lee]

2017-02-22 17:36 GMT+08:00 Kevin Wolf <address@hidden>:
> Am 22.02.2017 um 10:29 hat Jaze Lee geschrieben:
>> 2017-02-22 17:17 GMT+08:00 Kevin Wolf <address@hidden>:
>> > Am 22.02.2017 um 10:05 hat Jaze Lee geschrieben:
>> >> I test on cache=none with sata disk, because i do not have ssd in my pc,
>> >> and I do not find any performance improved.
>> >>
>> >> I do not know why the performance is not be improved....
>> >
>> > Most likely your disk is just too slow for the memory copy to make any
>> > significant difference, and the memcpy cost is dwarved by the actual
>> > disk I/O cost.
>> >
>> > Have you tried backing the server with a ramdisk instead?
>>
>> No yet...
>>
>> Do you mean I should use ramdisk as the root disk of the vm?
>> then attach the rbd volume to it?
>
> Did you intentionally drop the mailing list CC?

Sorry, it is not intentional.....

>
> No, the VM should just directly use rbd as it used to. It's the rbd
> server that should operate on a ramdisk rather than your SATA disk,
> so that you get any physical disk out of the way (because physical
> disks, and even more so spinning rust, make things slow).

Oh, I think i should change to another host, with large memory....

Thank you.


>
> Kevin



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