[mythtv-users] NFS and remote backend
Wade Maxfield
mythtv at hotblack.co.nz
Fri Jan 11 21:43:52 UTC 2008
John Drescher wrote:
>> On my gigabit network, NFS from my backend (Athlon64 X2 4600+, 2GB RAM)
>> to a G5 tower gets about 18MB/s for any size transfer from 350MB to
>> 1.5GB.
> This is slow (compared to what I get between 2 Athlon64 computers). I
> assume that is because the G5 is a few years old.
>
I don't think it is because the G% is old, as G5 to G5 over AFP I can
get 50MB/s+, and from a Xeon Xserve to the G5 I can get 60MB/s+ sustained.
>> If I then delete the file from the G5 and copy the exact same
>> file again I reach speeds of up to 56MB/s (according to IPNetMonitor - a
>> Mac network tool which graphs network transfers in real time - so it's
>> not just a cached file at the Mac end)
>>
> I would say this probably is because of caching.
>
> John
Caching maybe at the server end, since I can see the data being
transfered over the network.
To add another data point, while one copy is going at 16MB/s I can
initiate another copy for a different file (same backend & hard drive to
a separate drive on the G5) and it will also get around 14-16MB/s for a
total network throughput of around 30-32MB/s
So I don't think it's a limitation of my network adaptors, switch or
cabling (or older G5 machines/etc). I'm wondering if there is some sort
of throttling or threading at play? Something to ensure responsiveness
or ability to handle multiple requests from multiple clients and not
dedicate all resources/performance for a single client/transfer?
- Wade
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