zfs send/receive: is this slow?

[Artem Belevich]

I've just tested on my box and loopback interface does not seem to be
the bottleneck. I can easily push through ~400MB/s through two
instances of mbuffer.

--Artem



On Fri, Oct 1, 2010 at 7:51 PM, Sean <sean at gothic.net.au> wrote:
>
> On 02/10/2010, at 11:43 AM, Artem Belevich wrote:
>
>>> As soon as I opened this email I knew what it would say.
>>>
>>>
>>> # time zfs send storage/bacula at transfer | mbuffer | zfs receive
>>> storage/compressed/bacula-mbuffer
>>> in @  197 MB/s, out @  205 MB/s, 1749 MB total, buffer   0% full
>> ..
>>> Big difference.  :)
>>
>> I'm glad it helped.
>>
>> Does anyone know why sending/receiving stuff via loopback is so much
>> slower compared to pipe?
>
>
> Up and down the entire network stack, in and out of TCP buffers at both ends... might add some overhead, and other factors in limiting it.
>
> Increasing TCP buffers, and disabling delayed acks might help. Nagle might also have to be disabled too. (delayed acks and nagle in combination can interact in odd ways)
>
>
>>
>> --Artem
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>
>