Comments

RBartlett wrote on 8/13/2007, 3:54 PM
5MBysec/sec isn't that good. Perhaps your PC's backup program is backing off too strongly with the fact that this isn't a local drive and Windows may have told it so. Are you using a 3rd party backup, MS Backup or simply windows explorer (drag and drop)?

Single hard disks with a gigabit capable interface rarely achieve 100Mbit/sec of throughput (the speed of FastEthernet, 10% of GigEth). However that is 12.5Mbytes/sec, so your transfer speed is especially under par.

How does the drive appear to the OS?

Via a mapped drive using nothing more than microsoft networking?
Via a special driver that without which you'd not even get a drive letter?
Via iSCSI / AoE drivers where the device is a target and your PC is an initiator?


Practically the onboard processors on these "gigastor" devices are rarely much more than what you'd have powering a PDA or smartphone. So it may be of little surprise to those who have a working knowledge of these class of devices to find that they can't saturate a gigabit ethernet link.

If you are using microsoft networking for drive letter access, then this may not be the native mode for the drive. So you may be able to change the protocol and increae the throughput.

Otherwise, one of the best ways forward is to use an old PC with a gigabit ethernet card. If your gig-eth attached hard disk has a USB2 port, you could then use the old PC with a Linux distribution (that could feasibly boot from flash) and then you may achieve 100-120MBytes/sec of throughput. Perhaps less if your gigabit ethernet card is based on 32bit PCI and you have a 32bit PCI shared bus that restricts the overall disk I/O to perhaps half the 120MBytes/sec figure. Which frankly is good going for a single IDE/ATA drive anyway.

farss wrote on 8/13/2007, 5:03 PM
As I've recently discovered also there's GigE and then there's GigE. It's not just the NICs and drivers either, the switches can make a big difference. This may or may not be overlt relevant in this case but it's certainly a factor in certain cases, like stream RT video over a network to multiple destinations.

Bob.
Chienworks wrote on 8/13/2007, 7:15 PM
Vic, how are you measuring 5000kbps? And is there any chance that you are actually getting a measurement of 5000KBps instead of Kbps? Big B is Bytes, little b is bits. If it's bytes then your speed is 40,000kbps, which isn't terribly shabby for fast ethernet. Still not fantastic, but passable. By comparison, DV is 30,000Kbps and fast ethernet usually handles 2 or three simultaneous DV streams.
RalphM wrote on 8/13/2007, 7:27 PM
Why not just take a file of known size and time the backup? The math gets pretty simple then.

You want Slow? This evening I accidently plugged in an external drive to an old USB 1 hub and set out to copy 9 GBytes. Had dinner, came back only to find the process was still proceeeeeeeeeding. May have to invest in a new hub...

RalphM