Surprisingly Great iSCSI Performance from QNAP TS-639Pro

[corndog]

Hello all,

This was so nice it seemed to be too good to be true, so I double-checked a few times, but here is what I'm finding with my testing of iSCSI:

I'm comparing both Windows Vista SP1 iSCSI client (NTFS filesystem) and Linux open-iSCSI client (ext3 filesystem)


Win Write Win Read Lin Write Lin Read Target
--------- -------- --------- -------- -------------
37.1MB/s 42.7MB/s 33.0MB/s 46.6MB/s ReadyNAS Pro X-RAID2
82.1MB/s 86.7MB/s 36.3MB/s 52.4MB/s EqualLogic PS5000E
56.0MB/s 90.6MB/s 39.3MB/s 61.6MB/s QNAP TS-639Pro


A couple important items that come out of this:

1. Windows iSCSI is faster than Linux open-iscsi. Of course, these are both "out of the box" and I'm sure I have to learn how to tweak linux open-iscsi to get better performance. I'll look into that and report back.

2. Check out the numbers from that QNAP! It is decidedly faster than NetGear, and on reads it is standing up to the EqualLogic that costs around $50,000

Interesting?

 

[hmurchison]

Not too shabby ..with an Atom processor even.

 

[thiggins]

How are you measuring the read and write speeds?

 

[corndog]

I generated a 30G file full of random characters on Linux using this command:

dd if=/dev/uraudom of=testfile bs=1024000 count=30000

Then I copied it to my VistaSP1 PC. I rebooted the VistaSP1 PC, and then connected to the iSCSI drive. I copied the 30G file to the iSCSI drive, and selected "More Information" on the copy dialog. At the beginning of the copy, the throughput numbers bounce around a bit, but toward the end it really stabilizes. I took the stabilized number. I also ran an MRTG graph and a live activity graph on my Procurve switch to verify the values Vista was giving me.

Then I rebooted the VistaSP1 PC again, and copied the file back FROM the iSCSI drive to measure the read. Measured speed the same way.

... that's the Windows Method

For Linux, I did this:

1. connect to the iSCSI drive, partition it, and format with ext3.
2. use the following command to write a 30G file of zeroes directly to the iSCSI drive:

dd if=/dev/zero of=testfile bs=1024000 count=30000

3. dismount the iSCSI drive and reboot the Linux client
4. remount the iSCSI drive and use the following command to read the file:

dd if=testfile of=/dev/null

I used a file of zeroes on Linux because I'm doing it "on the fly" and /dev/urandom is very slow. If I create the file from /dev/zero it's capable of immense speed.

 

[corndog]

So my next step was to do some research about tweaking performance in open-iscsi. According to the open-iscsi project web site, performance is their chief goal. So I figure it should not lag that far behind Vista.

But I run Gentoo, and one of the main things about gentoo is that you really have to do the tweaking yourself. Once you do, your system rocks, but with a piece of software like iSCSI, where network settings can effect your performance greatly, a lot of work with kernel parameters is needed (most likely anyhow).

So I figured I would try a "pre-tweaked" system just to see what I could expect. To this end, I got OpenSUSE 11.1 going on my test system. It has open-iscsi built right in, so I figured Novell has worked on tuning it nicely since it is part of the "released package".

... turns out I was right!

I have modified my numbers from the first post in this thread, for the NetGear and the QNAP, so here they are. Note: I haven't yet been able to test the EqualLogic - have to do planning and change control to do that.

Win Write Win Read Lin Write Lin Read Target
--------- -------- --------- -------- -------------
37.1MB/s 42.7MB/s 40.2MB/s 64.3MB/s ReadyNAS Pro X-RAID2
82.1MB/s 86.7MB/s 36.3MB/s 52.4MB/s EqualLogic PS5000E
56.0MB/s 90.6MB/s 40.1MB/s 92.3MB/s QNAP TS-639Pro



The ReadyNAS and QNAP are about even on writes (or maybe the Linux software hit a max of some kind) but I'm seeing that amazing read performance from the QNAP, just like I did in Vista!

Testing continues...