SATA over Gigabit? Worth it even?

For a laptop with just USB 2.0 and Gigabit Ethernet ports, how could one attach 2.5" SATA disks? Seemingly all sorts of mini NAS only has Fast Ethernet which is quite braindead. I would imagine the 1000 megabit/s Ethernet would be faster than the 480 mbit/s USB 2.0 if there would something that is USB powered and has an eSATA port. I thought this be trivial but I can't find anything.

I asked GlobalScale Technologies - DreamPlugs how much this baby actually consumes...

 

I think you math needs a bit of work re: how USB connect disks work vs how SMB/samba storage work. Even iSCSI storage.

The more protocol layers you add in, the slower things get.

USB connect is about three layers and a single wire. Just about any kind of storage over IP has 5 layers plus the usual ethernet connection collision problems plus router/switch throughput issues.

 

not true newsposter. A typical usb harddrive has around 20-30MB/s bandwith. Over GB Network I have a constant 100MB/s bandwidth.

Layers do matter, but not here, really.

 

RAID NAS or device to device transfers?

 

well, my "raid nas" is a windows home server (so no raid). but yes, all sorts of devices. if it's gblan, it's all 100MB/s

 

Are you trying to actually solve a problem / address an issue, or is this just theorycraft? Because if you actually have a practical use for this information, I think that you're thinking about this the wrong way.


(1) If you want to attach 2.5" SATA disks, you're looking mostly at USB 2.0. That is because 2.5" SATA disks are typically intended in situations where portability and convenience (i.e. a single USB 2.0 cable carries both data and power) are more important than raw performance.

People who want performance on external disks look at 3.5" SATA disks. A 3.5" disk is going to be faster than a 2.5" disk. It is going to be cheaper. And you will have many more connectivity options (USB 2.0, eSATA, Firewire, Gigabit Ethernet).


(2) People typically connect a drive to a NAS because they need to access that drive from multiple different machines on the network. People typically use eSATA because they want max performance out of their machine, and are willing to deal with the pain-in-the-butt that is eSATA. People typically use USB 2.0 because they want convenience and universal connectivity with multiple machines. Your post obviously talks only about performance - but is that what REALLY matters? Are you really willing to sacrifice all semblance of portability and convenience for the sake of performance?


(3) Connecting a drive to a faster connectivity interface does not mean a faster drive. A data transfer process will only happen as fast as the source can read or the destination can write. Best case scenario - a 2.5" drive can read SEQUENTIAL data (e.g. one large unfragmented file) at around 60MBps, and write at speeds much lower than that. Meanwhile, those drives read RANDOM data (e.g. multiple very small files) at speeds as low as 0.5MBps.

That means you're never getting above 60MBps transfer speeds on sequential reads, and can get as low as 0.5MBps on random reads. Doesn't matter if you hook the drive up to 10Gbps, Fibre Channel, LightPeak, telepathy, etc. You're not getting above 60MBps... and 60MBps is only going to be achievable in absolutely ideal, sterile, benchmarking conditions.

 

kent: actual 2.5" drives can nicely get up to 100MB/s read/write. and one could as well have a 3.5" drive connected, going even beyond that.

 

DavevPermen-

Yes, you are correct.

I should have been a little more clear in my post. MOST 2.5" SATA drives can get ~60MBps - ~80MBps max. You can certainly buy new 2.5" drives with high areal density that get 80MBps - 100MBps sequential reads speeds.

But then again, I still believe those high numbers are only relevant in benchmarking scenarios. In real-world scenarios, you're dealing with non-ideal, non-sterile, non-benchmarking environments. And you are highly unlikely to ever hit those numbers.

 

i actually hit the max numbers for my hdds about all the time (they are innercircle 120MB/s and outer circle 80MB/s, and most of my file transfers over GBLan are 100MB/s straight (most are in the region >=100MB/s).

but the really important question:
how can one spell my name so wrong??