Post your performance results

I ran some speed tests while I was trying to figure out all the crap about MTUs. I just copied and pasted from my other post (viewtopic.php?f=28&t=26902).

Hi Everyone!

Since no one responded I just went ahead with some trials. No offense taken because the post was LONG! :lol:

Before I give my test results here is my set up:
MBP (early 08, mac os x 10.5.6)
D-LINK DIR-655 Wireless Router (supports jumbo frame-9000, from my extensive research and Gigabit LAN ports, but MTU value is set @ 1492)
D-Link DGS-2205 (Gigabit Switch, also supports jumbo frame-9000, http://www.newegg.com/Product/Product.a ... 6833127083)
ReadyNAS Duo (MTU 7936)
Hostname: ReadyNAS
Model: ReadyNAS Duo [X-RAID]
Serial:
Firmware: RAIDiator 4.1.4 [1.00a042]
Memory: 256 MB [2.5-3-3-7]
IP address: 192.168.0.199
Volume C: Online, X-RAID, 2 disks, 76% of 925 GB used

All day I've been reading other people's post in regards to performance Mac/PC, ReadyNAS Duo/PRO... I've been messing around with the MTUs and file sizes. Here we go.
I did my best to get the numbers.

Note: The way I changed my MTU values were via Terminal by using the "sudo ifconfig en0 mtu" command. I double, triple checked MTU values before, after and during the file transfers. All of the file transfers were drag & drop over AFP.

Test 1
MBP MTU: 1500
NAS MTU: 7936
File Size: 4.25 GB
Read (from NAS to MBP): Average 42.1 MB/s, Peak 43.0 MB/s, Range 34 MB/s to 42 MB/s
Write (from MBP to NAS): Average 9.5 MB/s, Peak 11.1 MB/s, Range 9 MB/s to 11 MB/s

Test 2
MBP MTU: 7936
NAS MTU: 7936
File Size: 4 GB
Read (from NAS to MBP): Range 36 MB/s to 37 MB/s
Write (from MBP to NAS): Range 9.5 MB/s to 10 MB/s

I thought this was really odd because there was no change in any of the transfer speeds. So, I unmounted the drives and remounted it and that's when the transfer speed kicked up!

Test 3
MBP MTU: 7936
NAS MTU: 7936
File Size: 8 GB
Read (from NAS to MBP): Peak 52.3 MB/s, Range 49 MB/s to 51 MB/s
Write (from MBP to NAS): Peak 41.1 MB/s, Range 38.3 MB/s to 40 MB/s

Nice!!! A huge increase, but I think the read speed got a big jump because the file size changed to 8 GB. Huge improvement over the write speed.

This time I wanted to restart the MBP and NAS because I wanted to clear any cache (just my guess...). So I restarted both the NAS and MBP and changed the MTU on the MBP to 9000 to see what would happen.

Test 4
MBP MTU: 9000
NAS MTU: 7936
File Size: 4 GB
Read (from NAS to MBP): Average 35.5 MB/s, Peak 41.5 MB/s
Write (from MBP to NAS): Average 40.4 MB/s, Peak 41.3 MB/s

The read performance had decreased (from 50s to 40s) so I assumed that it was because the MTU value on the MBP didn't match the NAS MTU. So I reverted back the MBP's MTU to 7936 and restarted only the NAS to clear any cache.

Test 5
MBP MTU: 7936
NAS MTU: 7936
File Size: 4 GB
Read (from NAS to MBP): Average 36.0 MB/s, Peak 43.9 MB/s
Write (from MBP to NAS): Average 40.2 MB/s

So basically, using MTU value of 9000 or 7936 on the MBP had not that much effect. No significant difference in the read speeds. But I tried copying a 8 GB file on the same setting from Test 5.

Test 6
MBP MTU: 7936
NAS MTU: 7936
File Size: 8 GB
Read (from NAS to MBP): Average 51.5 MB/s, Peak 53.2 MB/s
File Size: 4 GB
Read (from NAS to MBP): Range 45 MB/s to 50.8 MB/s
Write (from MBP to NAS): Average 39.4 MB/s


Test Conclusions:
1) It's my believe (guess) that the read speed when the MTU on the MBP (either 7936 or 9000) is largely depended on the size of the file. The bigger it is 4 GB> the faster the read speeds.
2) Write speed will significantly improve when you put the MBP's MTU to 7936 or 9000. I now always hit an average of 40 MB/s.
3) My guess is that you should always mount and remount the NAS whenever you change the MTU values on the MBP (see test 1, 2 and 3).

Still remaining questions :roll: :
1) Does using jumbo frames reduce performance when streaming videos from the NAS?
2) For some reasons the MTU values on the MBP do not stick. I still have to change it each time after restart. It will always return to default value of 1500. Anyone know how to make the new MTU value stick?

Thanks a lot everyone!