Benchmark and comparison: Filetransfer via SCP to B04

[kuleszdl]

I did some "real-life" benchmarks on my B04 Pogoplug running archlinux which I intend to use mainly as NAS (for receiving backup files) and I thought some of you might be interested in the results.

Setup
- Pogoblug B04, 3W idle
- hard drive WDC WD3200BEVT-00ZCT0 (hdparm: 56.9 MB/s on SATA, 26.4 MB/s on USB in the Pogoplug B04)
- latest archlinux with Kernel 2.6.31.6
- encryption aes-cbc-essiv:sha256, key size 128bits (if used) using luks
- ext3 filesystem with default mkfs and mount settings
- transferring a large ISO-Image (Ubuntu 12.10-desktop, 753MB) over a 100MBit network from another host to the Pogoplug B04 via SCP
- reference system1: Fujitsu Futro S300, Transmeta 800MHz, 256MB, eSata via PCI card, 100Mbit network, 10W idle
- reference system2: Thinkpad X60, Intel CoreDuo 1,83GHz, 3GB, SATA, 100Mbit network, 14.5W idle

Results

- USB, not encrypted: 5.13MB/s 02:27
- USB, encrypted: 3.77MB/s 03:20
- SATA, not encrypted: 6.55MB/s 01:55
- SATA, encrypted: 4.25MB/s 02:57

- SATA, encrypted (reference system 1): 4.45MB/s 02:49
- SATA, not encrypted (reference system 2): 11.07MB/s 01:08

Conclusions
- It looks like the USB connection is causing quite a lot of overhead on the Pogoplug.
- The slow 100Mbit network connection is probably not the bottleneck in my scenario, as reference system 2 gets quite a good throughput.
- Disk encryption further slows down things, but not *that* dramatically. It would be interesting to see if it's the SSH encryption or the luks encryption that causes more impact (maybe with a direct transfer over netcat).

Your mileage may vary, but of course I would be interested in how much.

[WarheadsSE]

Also the low RAM, but yes. The USB implementation on this board sucks at the moment.

[kuleszdl]

I did some more testing with other protocols and a different drive (WDC WD2500YS, 57,99MB/s in hdparm):

FTP (via vsftpd)
Sata, not encrypted: 11.4 MB/s - 789884928 bytes sent in 67.65 secs (11401.9 kB/s)
Sata-encrypted: 4.4 MB/s - 789884928 bytes sent in 176.36 secs (4373.8 kB/s)

SCP
Sata, not encrypted: 5.9MB/s 02:08
Sata encrypted: 4.7MB/s 02:42

Probably the block size of the cipher, the drive and the FTP buffer don't play together nicely, otherwise plain FTP would not be faster than SCP/SSH on the same encrypted filesystem? I also tried a pure hdparm read comparison over the Sata port:

Not encrypted:
Timing cached reads: 480 MB in 2.00 seconds = 239.82 MB/sec
Timing buffered disk reads: 188 MB in 3.01 seconds = 62.54 MB/sec

Encrypted (128bits):
Timing cached reads: 406 MB in 2.00 seconds = 202.96 MB/sec
Timing buffered disk reads: 18 MB in 3.09 seconds = 5.82 MB/sec

Encrypted (256bits):
Timing cached reads: 362 MB in 2.00 seconds = 180.90 MB/sec
Timing buffered disk reads: 14 MB in 3.30 seconds = 4.24 MB/sec


Any ideas on how to further increase crypto performance? (Except only placing client-side encrypted files on the NAS of course)

[WarheadsSE]

Working out the encryption accelerator chip on the device, which is note documented or coded anywhere in the kernels as I have found them.

[shv]

@kuleszdl: You can find some figures on drive encryption performance with Kirkwood processor in the following thread: http://forum.doozan.com/read.php?2,3389,3397

[kuleszdl]

I already saw them before, thanks. I was just interested whether the Oxynas performs differently here.