Copying over LAN, getting 46MB/s writes to ZFS RAIDZ pool

[David Hunt]

Mac Pro 2,1 running 10.7 Lion & MacZFS 74.3

 

I have a pool that is 5x2TB and I am transferring data over Gigabit NIC from a Windows computer that is reading from 2x4TB. The arrays themselves can easily hit 200+MB/s, so I was expecting the LAN to be the bottleneck at about 80-90MB/s. When I run zpool iostat it is very solid on 46.0-46.2MB/s.

 

I tried adjusting some settings I found on the net related to the /etc/sysctl.conf file. I even tried copying another file simultaneously from the Windows computer to OSX (but to a USB drive) and the network meter did jump up another 20MB/s which indicates it maxed out the speed of the USB drive and is not a network limitation.

 

I have done various benchmarks and file copies on ZFS pools on the system before I commited to this and in every case the ZFS pool could do 150-250MB/s no problem.

 

It looks to be just something very specifically to the ZFS pool over network. It's not a game changer. That's still far more then is need for streaming movies. But I was looking for a solution as it will still affect transfer speeds when uploading to the server. Currently uploading about 6TB and it's going to take about 2 days.

[Dave Cottlehuber]

On 30. Oktober 2013 at 01:39:18, David Hunt (westro...@gmail.com) wrote:
>
> Mac Pro 2,1 running 10.7 Lion & MacZFS 74.3
>
> I have a pool that is 5x2TB and I am transferring data over Gigabit
> NIC
> from a Windows computer that is reading from 2x4TB. The arrays
> themselves
> can easily hit 200+MB/s, so I was expecting the LAN to be the bottleneck
> at
> about 80-90MB/s. When I run zpool iostat it is very solid on 46.0-46.2MB/s.
>
> I tried adjusting some settings I found on the net related to the/etc/sysctl.conf
> file. I even tried copying another file
> simultaneously from the Windows computer to OSX (but to a USB
> drive) and
> the network meter did jump up another 20MB/s which indicates
> it maxed out
> the speed of the USB drive and is not a network limitation.

The following creates a 1Gb ramdisk, you could use a variation on this to try to eliminate drive speed:

diskutil erasevolume HFS+ 'ramdisk' `hdiutil attach -nomount ram://2097152`

-- 
Dave Cottlehuber
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