Anyone w experience using SATA or eSATA for backup.

[MplsBob]

I have seen external drives that can be connected via eSATA and some that can be connected via SATA.

Do either of these approaches appreciably shorten backup times over USB 2.0 or FIrewire 400/800?

 

[Lord Evermore]

SATA and eSATA are the same thing, as far as data transfer speeds, it's just a connector difference.

You could possibly see significant throughput differences. A single hard drive's sustained transfer when writing is under 60MBps for all but the very fastest (Raptor) possibly, and that's when it's at the beginning of the disk. Access times are a lot worse with Firewire/USB, however a backup doesn't particularly need rapid seeks. 60MBps is the limit for USB2.0, and only 50MBps for Firewire400, but actual performance is always much lower than that. Even a 5400RPM drive is generally good enough to max out the transfer rates.

If you've got the option and you want performance, then eSATA is the way to go. But you limit yourself to only having a drive that will work on computers with eSATA ports for accessing data on that drive. That may not be an issue of course if all you're doing is performing backups with it.

 

[MplsBob]

Thanks for your quick reply, you with the biblical sounding handle.

 

[Pabster]

Yes. (e)SATA is faster than both Firewire and USB 2.0, and significantly.

 

[MplsBob]

I know that (e)SATA is considerably faster from a theoretical point of view. I was hoping I could find someone who had some actual experience with it. As I have already found in my own experience, there can be a substantial difference between theoretical and what you actually get.

Yes, I would expect (e)SATA would most likely be faster, but by roughly how much.

 

[homercles337]

I have a 300GB SATA drive for backup and when i do backup its done before i know it.

 

[The Mailman]

i actually had a similar question, so thanks as well

ill be going USB though just to be safe since I may need compatability with other PC's should the need arise

if the transfer rate is similar, id rather side with compatability

 

[RebateMonger]

I think you might see a large variation depending on sizes and number of files being copied, the drive system of the PC that's the host, the controller chipsets, and the external drive itself.

Here's some backups that I ran tonight. 10GB of downloaded files (drivers, trial programs, etc.), from my desktop (XP Professional with 120GB Western Digital IDE drive). All were NTBackups from that drive to the various external drives. The XP computer's Intel IDE controller is running in Ultra DMA Mode 5. Canopus Raptor Test shows my PC's IDE drive at 26MB/sec Read and 26MB/sec write speed.

And, yeah, I imagine that my file transfer rate is being limited by my WD 120GB hard drive. With a faster host desktop drive, the external SATA might shine (as evidenced by its significantly faster VERIFY times).

By the way, the same Canopus Raptor Test shows the SATA external drive at 70MB/sec read and 60MB/sec write speed.

----------------------------------------------
NTBackup results
Directories: 1438
Files: 11967
Bytes: 9,721,129,005
----------------------------------------------
SATA 1
Si3112 PCI SATA controller and Seagate 320GB SATA 7200.10 drive in Apricorn SATA external housing.
Backup Time: 11 minutes and 19 seconds
Verify Time: 4 minutes and 41 seconds

Firewire 400
TI PCI Firewire controller and WD 80GB IDE drive in older AcomData Firewire 400 external housing.
Backup Time: 12 minutes and 50 seconds
Verify Time: 7 minutes and 51 seconds

USB 2.0
Built-in Intel USB 2.0 controller and WD 120GB IDE drive in older AcomData USB 2.0 exernal housing.
Backup Time: 13 minutes and 5 seconds
Verify Time: 7 minutes and 31 seconds
-------------------------------------------------

All of these transfer rates are in the 10-15 MegaBytes per second range. I've seen smaller (1GB) transfers in the 17-22 MegaBytes per second range. When backing up large stores on my Servers (70 to 300GB), both the USB and the SATA transfers fall to 7 to 8 Megabytes per second overall.

I'm in the process of putting together two Dell 830 servers (with Adaptec CERC SATA controllers). These will have PCI-E Si3132 SATA controllers for hotswap, and internal SATA hotswap trays filled with Seagate 7200.10 SATA drives. Hopefully (!) these will do better.

I have one combo external drive that will run Firewire 800, but it seems there are NO functional drivers for Server 2003 for Firewire 800 controllers, so I haven't played with it.

 

[corkyg]

In theory it works perfectly. I have an eSATA enclosure and a backplane adapter that can connect to a mobo's SATA port. In effect, this extends an internal SATA port for external use.

It works with some eSATA enclosures, but not all. The problem is "Delayed Write Errors" are almost constant. And, since it is electrically connected to an internal SATA port, the option of turning off write caching for an external drive is grayed out - it seen by Windows as Internal.

It might be possible with a PCI SATA controller card that has an external port. I don't - haven't tried that. And, some external cases may be better than others. But - be prepared for those errors.

So far I haven't found a solution for that, and my eSATA case is presently shelfware.

eSATA

 

[Pabster]

A rough recall of transfers I've done would suggest about 40MB/s over eSATA versus 20-25 on Firewire and 20 or less on USB 2.0. So I'd say about a 50% improvement.

 

[RebateMonger]

Originally posted by: corkyg
It might be possible with a PCI SATA controller card that has an external port. I don't - haven't tried that. And, some external cases may be better than others. But - be prepared for those errors.

My SATA controller has both external and internal ports. I don't have a drive hooked up at the moment, but as far as I can see, Windows treats external SATA drives exactly like internal drives - you can't optimize them for quick removal or set any other properties that would treat them like removable drives.

 

[Lord Evermore]

I have my IDE drive connected to my nf570 SATA port using an adapter, with the port set to operate in IDE mode, and in the drive properties I have the option to uncheck Enable write caching, although I still can't select the Optimize for quick removal option.

 

[RebateMonger]

I connected my Seagate 7200.10 320GB drive (in Apricorn SATA external housing) to my external SATA port (Si3112 chip) and I can't set the "Write caching and Safe Removal" page. It appears to be set (greyed out) to "Optimize for Performance", which turns on write caching.

The drive shows up in Windows XP Device Manager as "ST332062 OAS SCSI Disk Device" and the controller shows up in the SCSI and RAID controllers as "Silicon Image SI 3112 SATALink Controller".

 

[MplsBob]

What an impressive collection of replies!

Thank all of you for taking the time to respond with so much detail and thought.

 

[MplsBob]

I slipped up and failed to include one additional piece of information, it was one of my "senior's moments".

I normally run my PC using a 164GB Hitachi drive as c: drive.

Briefly I had my hands on a 74GB Raptor to use as my c: drive and was stunned to see that one single change reduced my backup times drop from 12+ minutes to 7+ minutes.

So it appears that changes at both ends of the connection can have a dramatic impact.

 

[corkyg]

Originally posted by: Lord Evermore I have my IDE drive connected to my nf570 SATA port using an adapter, with the port set to operate in IDE mode, and in the drive properties I have the option to uncheck Enable write caching, although I still can't select the Optimize for quick removal option.

Not all mobos and cards allow setting a SATA port to IDE mode. Unless you can optimize an eSATA drive for quick removel, it will probably get too many DWE's so as to make it unusable.

I'm waiting for the first laptop to have an external SATA port! Now that would be cool.

 

[Auric]

corkyg, I donut see why eSATA should have DWEs; given proper shielding it should function identically as if mounted inside. Have you tried eliminating the enclosure and/or even backplane from the equation?

 

[corkyg]

Originally posted by: Auric
corkyg, I donut see why eSATA should have DWEs; given proper shielding it should function identically as if mounted inside. Have you tried eliminating the enclosure and/or even backplane from the equation?

Yeah - it is the enclosure. I can run the drive outside the main case with a 16-in SATA cable and a Molex extender. No DWEs that way. That is my point - some cases can cause them. I have one that does.

 

[MplsBob]

corkyg:

Would you mind telling us what brand and model of external enclosure you are using.

 

[n7]

I have the VANTEC Nexstar 3 eSATA Aluminum 3.5" Enclosure, eSATA & USB2.0, Black, & it pwns.

I use eSATA if i can, since speed is far better than USB could dream to be.

 

[Auric]

Originally posted by: corkyg

Originally posted by: Auric
corkyg, I donut see why eSATA should have DWEs; given proper shielding it should function identically as if mounted inside. Have you tried eliminating the enclosure and/or even backplane from the equation?

Yeah - it is the enclosure. I can run the drive outside the main case with a 16-in SATA cable and a Molex extender. No DWEs that way. That is my point - some cases can cause them. I have one that does.

Ah, so. A "special" enclosure for SATA alone doesn't really make any sense precisely because it can only cause problems from the added electronics. All that is required, obviously, is the SATA cable and power so the latter may as well come from a switched case source or otherwise an external brick with any el-cheapo DIY or otherwise container to safely hold the drive. If an enclosure with internal power is desired for easier portability then any old bargain-bin USB model could simply be gutted and/or modded.

 

[RebateMonger]

I'm trying this this Apricorn external SATA housing. So far, so good. It has NOTHING between the SATA connector and the drive. The only internal electronics are for powering the LED and the internal fan.

I'm also experimenting with Granite Digital's hot-swap trays. The $59 LCD-version trays include a fan to cool the drive.

 

[Auric]

I considered the GD system myownself awhile ago and it seemed groovy until realizing the drive's own connectors would suffer wear each time it was inserted and removed. Maybe okay for RAID but removeable backup... not so much.

 

[RebateMonger]

I just tested the backup speed of a new Dell Server with a PCI-E SATA controller hooked to a removable internal SATA drive. I'm shocked. The transfer rate for 70GB of data is IDENTICAL to the rate I'd expect from a USB 2.0 transfer.

Data Source:
Dell PE830 Server with Dell CERC 6-channel SATA RAID controller and two 160GB SATA drives in RAID 1 configuration.

Backup Drive:
Seagate 320GB 7200.10 SATA drive on Si 3132 PCI-E SATA controller in Granite Digital Internal Removable SATA Tray

Transfer rate for NTBackup of 70 GB of data:
8 MegaBytes/Sec
--------------------------------------------
Backup Time: (2 hours, 25 minutes)
Size (on disk) 70GB
Files: Approx 110,000

Verify Time: (19 minutes)
Size (on disk) 70GB
Files: Approx 110,000
---------------------------------------------

Note how fast the VERIFY is. I'm not sure what's happening here. Anything I'm missing?

 

[Pabster]

Try using something other than NTBackup.