NAS or external drive

[per]

Hi All,

I am trying to figure our what would give me the fastest HD access:

Option 1. A NAS device (possibly with RAID) connected via the LAN port.

Option 2. An external HD with it's own power supply and on/off switch connected to one of the USB ports.

Any other useful advantages and disadvantages are also most appreciated.

Cheers,
Per

[yogev_ezra]

USB 2.0 is limited to 30 Megabyte/sec. Any other connection (IDE, SATA, LAN) will give better transfer rates (built in HDD gives around 60 Megabyte/sec). If you don't mind VOIDING your warranty, please check this: http://www.fit-pc2.com/forum/viewtopic.php?f=27&t=1241

[per]

Hi Yogev,

The mini PCI card looks good. I see you have installed one and I will follow the other thread to see what your speed test results will be.

USB 2.0 gives 30 MB/sec and internal drive 60 MB/sec. Do you have any idea of what the expected or theoretical speed would be for a NAS connected to the LAN port. I am looking at this one:
http://www.span.com/product_info.php?cP ... s_id=26187

Cheers,
Per

[yogev_ezra]

The LAN ports are connected via PCIe bus so their speed is limited by the speed of PCIe. The theoretical limit is listed here: http://en.wikipedia.org/wiki/List_of_device_bit_rates

From the list, the maximal limit for 1Gbit LAN is 128MB/sec, and the maximal limit of PCIe is 250MB/sec, but given that the theoretical limit of USB 2.0 is 60 MB/s and it only works at 30 MB/s in Fit-PC2, you cannot take the theoretical as granted, and the only way to know this, is to test the speed yourself... I assume the realistic transfer speed will be even less than 128MB/sec.

[per]

Hi Yogev,

I ran some tests tonight with CrystalDiskMark.

Internal HDD (160GB a few years old)
seq read speed: 50.86 MB/s
seq write speed: 51.23 MB/s

USB 2.0 connected external 500GB HDD 2.5'' USB powered
seq read speed: 31.32 MB/s
seq write speed: 17.39 MB/s

Test on Thecus N0205 NAS LAN connected with processor and own power
seq read speed: 33.55 MB/s
seq write speed: 15.79 MB/s

Result, the Thecus connected via LAN does not seem any quicker than a USB drive powered via the USB port. Interesting.

It would be great if you would have time to run CrystalDiskMark with the mini PCI card.

Cheers,
Per

[yogev_ezra]

I took the time to test a few of my disks with CrystalDiskMark, and the results are quite interesting:

CompuLab stock 2.5" 160GB SATA HDD (Hitachi, manufactured July 2009)
The results are exactly the same for internal Fit-PC2 connection and connection via mini PCIe card - both sequential read and write speeds are 60 MB/sec.

KingSpec Motive G1 2.5" 128GB SATA MLC SSD (manufactured March 2010, based on JMF612 SSD controller)
When connected internally:
Sequential read speed: 90 MB/sec
Sequential write speed: 75 MB/sec
When connected through MPX-3132 mini PCIe card:
Sequential read speed: 115 MB/sec
Sequential write speed: 106 MB/sec

This gives us a few conclusions:
1) For CompuLab stock "platter" disk, the transfer speed is exactly the same for internal connection and for mini PCIe connection via MPX-3132 bridge, and both times it's lower than SSD speed limit. This hints on hard disk max. throughput limit of about 60 MB/sec (which is below internal PATA->SATA bridge limit and below MPX-3132 bridge limit). So if you plan to use regular 2.5" disks, any bus that will provide you >60 MB/sec is enough, and in particular mini PCIe card provides better result than USB 2.0 or LAN connection.
2) For faster SSD disks, it looks like the PATA->SATA bridge throughput limit is around 90 MB/sec for reading and 75 MB/sec for writing (the SSD disk itself is capable of higher speeds). So if you plan to speed-up the internal disk in Fit-PC2, installing any disk with throughput >90 MB/sec will be good enough as it's impossible to reach more. On the other hand, PCIe bridge allows faster speeds of 115 MB/sec read and 106 MB/sec write, respectively. Here it looks like 115 MB/sec is the limit of the disk, and if higher throughput disks become available, the PCIe bridge will support them.
3) A side note on your Thecus NAS speed via LAN connection: I could not find the IC specification for Thecus NAS on the internet, but it could be that LAN is implemented via USB-to-LAN bridge, so the LAN speed is actually limited by USB 2.0 speed...

[per]

Hi Yogev,

Very interesting benchmarks indeed. Thanks.

The Thecus test was actually done with two 2.5'' SSD drives so you are probably right about the LAN/USB bridge. They also say in the test that standard NAS's are usually much faster (but also much larger and power hungry of course).

Here is the Thecus test:
http://www.legitreviews.com/article/1135/1/

Cheers,
Per