How To Build a Really Fast NAS - Part 5: iSCSI

[00Roush]

Thanks for testing this out (http://www.smallnetbuilder.com/content/view/30585/77/). As I actually did a similar test last week on my home network I wondered if others would have the same results. From what I can tell you ended up at the same result. Using iSCSI didn't increase performance over what can be obtained using SMB/CIFS. This of course is just on Win XP PRO SP2. Using a different iSCSI target program or a different OS could give completely different results.

00Roush

[kevinherring]

I'm loving your perseverance on this Tim!

I bought a crossover cable (as I have no gigabit switch) during the week so I am going have a play with my ramdisk theory shortly when I get some time.

Keep up the good work :-)

[ChrisM]

Guys, I have to question your setup. I conducted a similar test about a month ago and found iscsi to be much faster that cifs/smb, especially on big copies. I wrote the results on my notepad so I will post them later. I was using Openfiler as the iscsi SAN and tested from both my desktop pc using MS initiator and also from my esx server. I use gigabit everywhere. I'll redo the tests and post later...

Chris

[Prof. Dr. YoMan]

Did you use IPsec on the iSCSI System?

This draws a lot of computing power.

Switching it off would help to achive more speed i guess.

And in an internal net no extra security is needed.

[thiggins]

Guys, I have to question your setup.
Different systems will product different results.
Sans Digital has reviewed the results and said that they are in line with their testing. Obviously, the MN4L+ is not optimized for iSCSI.

[thiggins]

Did you use IPsec on the iSCSI System?

No. The connection was unencrypted.

[00Roush]

Guys, I have to question your setup. I conducted a similar test about a month ago and found iscsi to be much faster that cifs/smb, especially on big copies. I wrote the results on my notepad so I will post them later. I was using Openfiler as the iscsi SAN and tested from both my desktop pc using MS initiator and also from my esx server. I use gigabit everywhere. I'll redo the tests and post later...

Chris

Maybe I will give Openfiler a shot. I used iSCSI Cake target software on Win XP PRO SP2 and the MS initiator. I don't recall actually running iozone when I had the iSCSI setup as using the windows copy/paste showed slower results than SMB/CIFS. From what I recall I did not have IPsec enabled.

If you guys want to see some results I could probably set up the software again. Let me know.

00Roush

[Unregistered]

In my <limited> iSCSI experience, Jumbo frames makes a significant difference in performance. I assume due to the overhead of encapsulation data to real data is so much higher with small frames. Was all the testing done without Jumbo Frames?

Cheers

[00Roush]

In my testing with iSCSI so far I have not used jumbo frames. I didn't think it would make any difference as it never did with SMB/CIFS. Now that you mention it I remember reading some other info that showed a big improvement using jumbo frames with iSCSI. I'll try it and report back.

00Roush

[00Roush]

So I haven't got around to checking on the Jumbo frames... Instead I have found that with Ubuntu Server and Win Vista SP1 file copies using SMB/CIFS or iSCSI are faster than my previous tests of Win XP PRO. For example writes from my client (Vista SP1) to server (ubuntu server) hum at about 70-80 MB/sec. Reading from the server to the client is around 80-105 MB/sec. This is using single drives.

Also tested with Openfiler on the server and Win XP Pro on the client utilizing the same two computers. From what I recall read and write performance seemed capped at about 60 MB/sec. Next up I will try Win XP Pro on the server and Win Vista on the client with iSCSI and see what I come up with.

00Roush

[arnok666]

I have a Qnap ts439 pro with a 3 drive jbod.

i have tested many different file size copies from it to my vista x64 htpc.
GBlan no JF

iSCSI reports about 40MB/s as smb reports 6MB/s. when copying wind0ws dvr files..

It's crazy! but even on my XP sp3 box iSCSI is faster...

i'm not sure whats

[thiggins]

The SMB results sound very low.

Further testing I have done more recently shows improved iSCSI throughput than in the article. But when file size exceeds the iSCSI initiator's RAM size, throughput drops sharply.