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LAN performance dropped

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Mike Hope

Junior Member
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Feb 7, 2015
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As I already posted here I was very happy with the initial results of my first FreeNAS server and thought of adding a 10 GbE NIC later.

After that I wonderd if I missed something using the wizard. So I decided to delete the VDEV and do it all over using the proper menue actions.
I didn't find anything different except compression to choose.
But after recreating everything LAN throughput dropped from 110 MB/s (maxed out 1 GbE) to 80-100 MB/s for the very same data to transfer!
So what went wrong?

I did some local tests from the commandline on an uncompressed dataset:

dd if=/dev/zero of=testfile bs=1048576
^C297981+0 records in
297980+0 records out
312454676480 bytes transferred in 602.481468 secs (518612925 bytes/sec)
=> 495 MB/s, CPU Usage = 15%

dd if=testfile of=/dev/null bs=1048576
297981+0 records in
297981+0 records out
312455725056 bytes transferred in 551.480556 secs (566576141 bytes/sec)
=> 540 MB/s, CPU Usage = 5%

dd if=/dev/zero of=testfile bs=262144
^C1359652+0 records in
1359651+0 records out
356424351744 bytes transferred in 669.834712 secs (532107915 bytes/sec)
=> 507 MB/s, CPU Usage = 15%

dd if=testfile of=/dev/null bs=262144
1359652+0 records in
1359652+0 records out
356424613888 bytes transferred in 692.984025 secs (514333089 bytes/sec)
=> 490 MB/s, CPU Usage = 5%

So ZFS performance should be OK.
With 1 GbE not maxed out, 10 GbE will not make much sense.

Any hints?

Greets,
Mike
 
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Mike Hope

Junior Member
Joined
Feb 7, 2015
Messages
12
At least partially I think.
Some CIFS shares didn't have the Windows rights enabled. After fixing this I was back to maxing out 1GbE with large files.

However the performance on small files is significantly lower.
Shouldn't it be also high when reading of an SSD on the client while writing to the cache of freenas (the machine has 32GB RAM)?
I don't have any experience with 10GbE, so it might be just the overhead on 1GbE and I can expect higher throughput with 10GbE?

Most files transferred are larger (photos and videos) so thats not too much of a concern.
For backup purposes maybe I should consider some real backup software over robocopy ...
 

Bidule0hm

Server Electronics Sorcerer
Joined
Aug 5, 2013
Messages
3,710
Yes, it's probably the network overhead ;)
 

rumdr19

Member
Joined
Jan 18, 2015
Messages
28
I am sure is probably not your case, but I was having some issues with my CIFS data transfer speeds. After banging my head around, I noticed a section of my Ethernet cable (about 10ft) was running together with a power line. After rerouting the cable, my speeds increased from about 30MB to a constant 125MB. I knew running your Ethernet next to high voltage is bad because of noise entering the line, but never knew it could be that bad. Like a said, probably not your case, but maybe worth looking at.
 

Mike Hope

Junior Member
Joined
Feb 7, 2015
Messages
12
Thanks for mentioning.
My cables run at least partially in parallel because other routing would mean a great hassle.
But since I have full speed now that is not an issue for me.

Btw: I use shielded cables (STP), maybe yours was unshielded (UTP)?
 

rumdr19

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Jan 18, 2015
Messages
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