[HELP] Performance issues with TS439PII+

[tatcom]

Hi guys,

I recently bought a TS-439PII+ (FW 3.3.6 Build1110) which I'm using in RAID5 (EXT4) with 3x 2TB WD Caviar Black (WD2002FAEX) drives. I started testing system performance and have to say I have serious issues with throughput speed. No matter if I'm using AFP - as I'm copying files from a MBP (10.6.6) equipped with an Intel G2 series SSD - or SMB protocols, speed is nowhere near the advertised rates: it shows serious peaks and drops without steady performance.

Write speed to the NAS in RAID5 (EXT3 or EXT4) with AFP varies between 81 and 29MB/s, averaging near 35MB/s. I believe throughput should be WAY above this!

As I wasn't sure if it's a problem with the drives themselves, I broke up the RAID set and checked in JBOD and RAID1 modes. Throughput for write operations was a steady 91MB/s with read from the NAS being a constant 109MB/s in both cases.

Any ideas what could cause this significant degradation of speed?

 

[thiggins]

NAS throughput is highly dependent on what is being transferred. Best performance will be with large > 1 GB files, which provide sequential read/write, which is best case.
Folders of smaller files will produce considerably lower throughput due to drive head seeking.

 

[tatcom]

Sure thing Tim, I was testing throughput by transferring >12GB files between the MBP and the NAS.

Do you think the 6Gbps SATA interface might be a factor? (Although in JBOD and RAID1 it didn't have any effect on sustained speed.) BTW, can you tell me what HDDs Qnap uses for their products when they ship them to you for testing?

 

[thiggins]

Have you tried the same test transferring to another MacBook Pro or computer. The limitation could be the computer.

Drives used are usually described in each NAS' review. QNAP has been using Samsung Spinpoint F1 or F3 of late.

 

[tatcom]

...and we have a winner: the point goes to Tim!

I had some time for further testing the QNAP with other HDDs of different size and control interface and it came as a total shock to me, that the limiting factor was indeed the SSD in the MBP. I changed the computer I was copying from and the sudden drops disappeared from Network Monitor and all came out at a steady 84MB/s through AFP.

So everything works fine, though I'm a bit disappointed with the speed SAMBA provides, but I can totally live without it.

Once again, thanks for the tip Tim and keep up the excellent work with the site!

Cheers

 

[thiggins]

Thanks for reporting back.