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Review: Thecus N5200 Pro - NAS with an injection of iSCSI

by Steve Kerrison on 8 August 2007, 09:08

Tags: N5200 Pro, Thecus (4978.TWO)

Quick Link: HEXUS.net/qajgs

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Performance testing

N5200 Pro Performance

We used IOMeter version 2006.07.27 over SMB shares and, in the case of iSCSI mode, using NTFS.

Boston kindly provided us with five Seagate 7200.10 750GB SATA disks, so big thanks are in order. The disks were jumpered-up for 3Gbps operation.

Setup

The host machine for IOMeter was as follows:

ComponentDetails
CPU AMD Opteron 146 @ 2.5GHz
Motherboard ABIT AN8 Ultra (nForce 4 Ultra)
Memory 2.0GB PC3200 DDR @ 209MHz
Disks 4x Seagate 7200.8 250GB - RAID 10
Graphics NVIDIA GeForce 6800 GT 256MiB
Network NVIDIA network controller, 1Gbps, 9000byte frames
OS Microsoft Windows XP x64


The networking might that is the N5200 Pro's NICs can handle jumbo frames up to 16000bytes, but 8000 was the closest we could get to the host's maximum of 9000, so we set it to that.

Below is our IOMeter test regime:

Option/testConfiguration
Outstanding I/Os 10
Individual test run time 30 seconds
Read test access spec 1MB transfers
100% sequential
100% read
Write test access spec 1MB transfers
100% sequential
100% write
General usage access spec 64KB transfers
50% sequential, 50% random
33% write, 67% read


For comparison, we've included results for Thecus's four-disk rackmount 1U4500. Also in the fray is QNAP's TS-109 Pro, a single-disk solution.

The N5200 non-Pro was tested before our current NAS testing scheme was in place, so we've not included it in the graphs, simply to ensure consistency between results.

SMB performance

Windows File Sharing isn't as quick as NFS, iSCSI and a few others, but its use is widespread, so the N5200 has to deliver satisfactory throughput with it.

We don't have throughput test data for the 1U4500 below 250MiB file sizes, so please bear this in mind when considering the results.

Read performance first...

N5200 Pro

Here we can see that the 1U4500, which has the same motherboard, CPU and RAM under the hood as the N5200 Pro, edges in front of its five-disk companion.

The N5200 Pro's performance with a 1GiB test file proved significantly less than the other test subjects, which seems a little odd. We cannot put our finger on the reason but we might take a guess at the firmware having something to do with it, given the lack of architectural differences between N5200 and 1U4500.

As we've already stated, the 1U4500 is slightly quicker than the N5200 Pro. Since it has one less disk in its array, we'd wager that the reduction in RAID management overhead is what provides this edge. The single-disk TS-109 Pro does an outstanding job against the two big boys, shaming them at larger file sizes.

Also noteworthy is the fact that the N5200 Pro's performance peaks at around the 250MiB mark and starts to tail off (though not in any dramatic way) as the file size gets smaller still.

N5200 Pro

For write performance, the 1U4500 and N5200 Pro deliver similar levels of throughput, leaving the TS-109 Pro behind, although it does begin to catch up as the file size drops.

N5200 Pro

A very similar story can be told for the result of the "general" test, too. 512MiB of RAM helps deliver good throughput for larger file sizes, but get down in size, and the TS-109 Pro, with 128MiB, can put up a good fight.

The N5200 Pro's performance is in line with what we'd expect, given our experience with the N5200 non-Pro and 1U4500.

Now, let's throw multiple workers at the box and see what happens to our throughput.

N5200 Pro

Keep the N5200 Pro busy and it'll keep pumping out the data - for large requests at least. Our "general" test uses much smaller request sizes, and evidently this means that the N5200 Pro has enough requests to deal with when there's just one worker attached to it.

SMB performance is up to scratch then, for the most part. However, it's a little perturbing to see a single-disk solution outpace the RAID-bearing beasts in some situations. In others, though, the Thecus is well out in front.

iSCSI performance

We'd hope to see a performance improvement over SMB when using iSCSI, to help justify the N5200 Pro's extra cost over the N5200.

This is the first iSCSI-capable product to be processed in the HEXUS Labs, so we have no others to compare it against. We can, however, offer up our thoughts on the performance advantage over the more traditional file-transfer method of SMB.

N5200 Pro

The N5200 Pro delivered under 10MiB/s reads over SMB when dealing with a 1GiB file. Using iSCSI, that jumps to a ninja 35.64MiB/s.

As the file sizes shrink, so too does the performance difference. But whichever way you look at it, iSCSI delivers a throughput boost. Win!

RAID test

Having tested the N5200 Pro when all is well, let's see what happens when the RAID goes boom...

N5200 Pro

A dead disk doesn't damage data rates... much. There is a bit of a hit when you come to repair the array, but it's not a lot.

The real hit is the amount of time it takes to rebuild the array - in the order of several hours for our five 750GB disks. Fingers crossed that another disk doesn't die in the meantime (or you could use RAID-6 if you're paranoid).

Performance thoughts

So, we've had our first taste of iSCSI and we like it!

It wasn't as painful as the old days of SCSI, where termination and device IDs produced misery and confusion. The benefit of providing block-level access to a client is clear - things happen quicker.

SMB performance remains good, if a little flaky for larger file sizes. All aspects considered, we're fairly impressed.