• Home
  • Help
  • Search
  • Login
  • Register
Pages: [1]
Author Topic: Sheevaplug - e-SATA vs. USB 2.0 & Encryption question  (Read 4548 times)
hausschuh
Newbie
*

Karma: 0
Posts: 33


View Profile
« on: April 18, 2010, 05:18:19 AM »

If I would buy the e-SATA version of the Sheevaplug and connect it to a 1GBit router and e-SATA hard drive I will get a theoretically transfer rate of 125MB/s from the Sheevaplug to my Desktop computer since the bottle neck is the 1GBit router. I was fine with the idea but then I read this benchmark: http://computingplugs.com/index.php/SheevaPlug_Performance#Network_Performance
If my interpretation is correct - the bottleneck is not the 1GBit router but the CPU of the Sheevaplug which will not allow a transfer rate above ~25MB/s.
So an USB 2.0 version and an USB 2.0 HDD would do the job (and save me some money). Can anybody confirm that the Sheevaplug is limited to less then 30MB/s over LAN?

Besides I'm interested in encrypting my data. I found the Western Digital My Book Essential with hardware encryption. Since it is hardware encryption it should not effect the CPU of the Sheevaplug to decrypt the data. The problem is you need the Western Digital Tool to "mount" the hard drive and after I wrote an e-mail to the support they confirmed there is no linux version of the software. Is there alternative software which can "mount" the hard drive without the Western Digital Tool?
If not - what is the performance of software encryption and which software do you use? TrueCrypt, Loop-AES?

Thanks in advance.
Logged

theblop
Newbie
*

Karma: 0
Posts: 21


View Profile
« Reply #1 on: April 18, 2010, 05:55:26 AM »

The practical transfer rate limit of GB Ethernet is likely to be around 50-70MB/s and more often than not, 20-30MB/s depending on your switch/cables/etc...

The plug has a hardware encryption chipset but so far I don't think anything is really using it (and in particular Truecrypt or dmcrypt). I get about 5-10MB/s with dmcrypt on a USB2 disk with my sheevaplug. I got about 5MB/s with some tests with truecrypt as well. Maybe it would be slightly faster with eSata but I don't think it would be significant (haven't seen any bench about this yet though)

If I would buy the e-SATA version of the Sheevaplug and connect it to a 1GBit router and e-SATA hard drive I will get a theoretically transfer rate of 125MB/s from the Sheevaplug to my Desktop computer since the bottle neck is the 1GBit router. I was fine with the idea but then I read this benchmark: http://computingplugs.com/index.php/SheevaPlug_Performance#Network_Performance
If my interpretation is correct - the bottleneck is not the 1GBit router but the CPU of the Sheevaplug which will not allow a transfer rate above ~25MB/s.
So an USB 2.0 version and an USB 2.0 HDD would do the job (and save me some money). Can anybody confirm that the Sheevaplug is limited to less then 30MB/s over LAN?

Besides I'm interested in encrypting my data. I found the Western Digital My Book Essential with hardware encryption. Since it is hardware encryption it should not effect the CPU of the Sheevaplug to decrypt the data. The problem is you need the Western Digital Tool to "mount" the hard drive and after I wrote an e-mail to the support they confirmed there is no linux version of the software. Is there alternative software which can "mount" the hard drive without the Western Digital Tool?
If not - what is the performance of software encryption and which software do you use? TrueCrypt, Loop-AES?

Thanks in advance.
Logged

peter a
Full Member
***

Karma: 0
Posts: 132


View Profile
« Reply #2 on: April 18, 2010, 08:52:14 AM »

I think the limiting factor may be the gigabit link , I can access the hard drive at 50-60 megs Bytes / Sec if I`m doing a Md5 sum of any files on the drive , But limited to 35 megs /sec over the network.   

Using Esata over usb is faster , but how many time do you want that sort of speed .
Logged

Blüto
Newbie
*

Karma: 5
Posts: 38


View Profile
« Reply #3 on: April 21, 2010, 06:32:31 AM »

... I was fine with the idea but then I read this benchmark: http://computingplugs.com/index.php/SheevaPlug_Performance#Network_Performance
If my interpretation is correct - the bottleneck is not the 1GBit router but the CPU of the Sheevaplug which will not allow a transfer rate above ~25MB/s.

I don't have an eSATA-enabled plug yet (I wonder what pathetic excuse GlobalScale will come up with for not shipping the GuruPlugs this month, either) but I anticipate disk I/O around 100 Mbyte/sec and ethernet 50 Mbyte/sec, or 40% of theoretical capacity. This rule-of-thumb predicts 24 Mbyte/sec for USB ((480,000,000 * 0.4) / 8 = 24,000,000) which is very close to the observed value, though we might do better than predicted with eSATA because it's fast enough to make device/filesystem/protocol optimizations worth pursuit. (Euro eSATA Sheeva owners, do tell!)

In your case, I believe encryption will be the bottleneck. The Sheeva CPU ostensibly has hardware encryption, but there's evidently a lack of  kernel/API/library support for it yet, so if filesystem encryption is a must-have feature it probably won't matter which flavor of plug you buy because the plug's performance will be CPU-bound rather than I/O bound until the necessary software is available.
 

Logged

Blüto
Newbie
*

Karma: 5
Posts: 38


View Profile
« Reply #4 on: April 22, 2010, 04:00:31 AM »


See CTERA CloudPlug Reviewed at SmallNetBuilder.com
Logged

peter a
Full Member
***

Karma: 0
Posts: 132


View Profile
« Reply #5 on: April 22, 2010, 04:37:03 AM »

I can agree with those figures :- ( ESATA )

I get 30-40 M bytes / Sec over the network with an EXT3 formatted drive , and over 50 direct access to the drive.
That is still not bottle necked by the cpu , but by the gigabit link .
I tried formatting the drive with ntfs-3g and was only getting about 6 M / Sec with 100% cpu.



Logged

hausschuh
Newbie
*

Karma: 0
Posts: 33


View Profile
« Reply #6 on: April 22, 2010, 04:40:49 AM »

Thank you for your replies.

Quote
Using Esata over usb is faster , but how many time do you want that sort of speed .
Well, I didn't tell the whole story  Smiley
I'm going to use it as High Definition Storage where files might be around 1-8GB for 1 file. That's where speed matters unpacking RAR files and stream the stuff over the LAN.

Quote
I can access the hard drive at 50-60 megs Bytes / Sec if I`m doing a Md5 sum of any files on the drive
Are you talking about a USB or eSATA hard drive?


Too bad there's no real speed benefit for the eSATA. I guess I'll wait for the GuruPlug Benchmarks and reconsider my plans - although I think the speed result will be the same (since the hardware is almost the same).
And I have to give up my software encryption plans  Cry

Logged

peter a
Full Member
***

Karma: 0
Posts: 132


View Profile
« Reply #7 on: April 22, 2010, 05:45:08 AM »

Quote
Are you talking about a USB or eSATA hard drive?

Esata !!!

Usb is like formatting your drive with NTFS , so so slow.
Logged

hausschuh
Newbie
*

Karma: 0
Posts: 33


View Profile
« Reply #8 on: April 22, 2010, 05:46:54 AM »

You wrote your answer while I was composing mine  Smiley
You put ESATA in brackets before I read it.
Logged

Blüto
Newbie
*

Karma: 5
Posts: 38


View Profile
« Reply #9 on: April 22, 2010, 09:13:34 AM »

Too bad there's no real speed benefit for the eSATA.

I'm not sure that I agree with you 100% on your police work there, Lou. -- Marge Gunderson [Frances McDormand] in Fargo (1996)
 
  • We don't know how far the CTERA implementation varies from the standard SheevaPlug, that is, whether they've economized on RAM or other components that could affect benchmark performance.

  • Copying a DVD-sized file to and from a NAS device isn't a terribly useful metric by itself. For example, how well does the plug handle large collections of randomly-sized files, as you'd encounter in a backup scenario?

  • How well does it handle concurrent I/O streams in either or both directions? This test in particular would cripple USB.

  • NTFS, FAT32, and (N)EXT3 aren't the only (let alone the best) filesystems available under Linux, they're the only ones CTERA chose to support with their proprietary firmware. The results could be different under JFS, XFS, ReiserFS, et al.

  • NFS is roughly twice as fast as CIFS, and is compatible with most network media player-type appliances and software like MythTV, SageTV, XBMC, NMT, WD, etc.

  • iSCSI looks like it might be as fast or faster than NFS.

  • Speaking of media, a 1920x1080 Blu-Ray rip has a bitrate of, what, 20 - 45 Mbit/sec (3.125 - 5.625 MByte/sec)? I don't see a problem reading, writing or streaming HD files regardless of I/O interface in that case (except USB, and except multiple streams concurrently).

  • Enabling Jumbo frames can significantly improve Ethernet throughput, if your routers, switches and NICs can handle them.

  • How good is your DAS box? You can't realistically expect datacenter performance from a consumer-grade, controller-less, non-RAID enclosure.

  • You simply can't buy a better NAS for the money. Not as a development kit (BeagleBoard, FitPC) or finished product (Synology DS209, QNAP TS-219P, etc.)


Logged

hausschuh
Newbie
*

Karma: 0
Posts: 33


View Profile
« Reply #10 on: April 22, 2010, 09:37:37 AM »

Valid objections.

Quote
Copying a DVD-sized file to and from a NAS device isn't a terribly useful metric by itself. For example, how well does the plug handle large collections of randomly-sized files, as you'd encounter in a backup scenario?
Actually I won't use it for backup purpose but for DVD-sized files (primary HD mkv files between 1-8GB). So these benchmarks represent my purpose.

I guess the other objections need more reading and information input on my side.

Quote
You simply can't buy a better NAS for the money. Not as a development kit (BeagleBoard, FitPC) or finished product (Synology DS209, QNAP TS-219P, etc.)
You're right. Right now I have a NSLU2 from Cisco/Linksys and I'm going to upgrade. But I would like to see a tremendous speed increase to justify the capital investment.
Logged

peter a
Full Member
***

Karma: 0
Posts: 132


View Profile
« Reply #11 on: April 22, 2010, 10:08:29 AM »

Sorry, but the Sheevaplug will trash the NSLU2 on any test by a massive amount.

The sheevaplug is a completely different beast than the NSLU2 , You have 512 meg of ram which will do real work , not the 32 megs of the  NSLU2.
So you can run MYSQL and PHP and give it 4 times the NSLU2 as in total.
Logged

Pages: [1]
Print
Jump to: