eSATA or USB3

[dalben]

I'm looking at getting an external HDD enclosure for my  server which is running out of space.  USB3 and eSATA are the most common interfaces and I have both available.  Is there any difference in technologies that make one better than the other in UNRaid, other than the fact USB3 is 5Gbs whereas eSATA can push to SATA3's 6Gbs ?

[JorgeB]

Performance should be similar for HDDs, for SSDs use eSATA.

[robertoal]

I found this reply interesting, and it probably answers your question: (Source)

 

"One thing nobody mentioned was latency. ESATA is just a regular SATA port, it acts identically to an internal SATA port. USB on the other hand is a different beast. Anything going to or from a USB port will have additional latency, there is no way around it. This is why the quick file access seems "faster" and more responsive on something connected via ESATA vs USB 3.0. The USB device needs to establish a session, the SATA device just spits it out. ESATA also supports all the advanced commands from the SATA AHCI spec, including NCQ and OoO reads.

 

I use a ProBox RAID and get 80~120 MB/s transfer to / from a four disk RAID-0 array. Less when working with a RAID-5 array of course.

 

In short, if you have eSATA then use eSATA, it will always win vs a USB interface regardless of the bandwidth involved. A single HDD will never saturate the bandwidth available on a SATA 1.5 port, much less a SATA3 port."

[dalben]

I found this reply interesting, and it probably answers your question: (Source)

 

"One thing nobody mentioned was latency. ESATA is just a regular SATA port, it acts identically to an internal SATA port. USB on the other hand is a different beast. Anything going to or from a USB port will have additional latency, there is no way around it. This is why the quick file access seems "faster" and more responsive on something connected via ESATA vs USB 3.0. The USB device needs to establish a session, the SATA device just spits it out. ESATA also supports all the advanced commands from the SATA AHCI spec, including NCQ and OoO reads.

 

I use a ProBox RAID and get 80~120 MB/s transfer to / from a four disk RAID-0 array. Less when working with a RAID-5 array of course.

 

In short, if you have eSATA then use eSATA, it will always win vs a USB interface regardless of the bandwidth involved. A single HDD will never saturate the bandwidth available on a SATA 1.5 port, much less a SATA3 port."

 

Thanks.  That settles the argument for me I guess.  Now to fund the right enclosure.

[robertoal]

Could be a cheap one because there is no Electronic wizardry going on in a esate enclosure.. Just sata tot sata :-)

 

Sent from my A0001 using Tapatalk

 

 

[John_M]

I use one of these to expand the capabilities of my four-bay HP Microserver Gen8: http://www.icydock.com/goods.php?id=201. I use it in eSATA mode (though FWIW it also supports USB 3), connected to one of these: https://www.amazon.co.uk/gp/product/B00AZ9T2SW for a 6 Gb/s eSATA connection. The combination works very well and I use the two internal SATA ports for a pair of cache SSDs. The Icy Cube's port multiplier passes SMART status without difficulty, unlike a two-drive StarTech external case I tried.

 

[dalben]

I use one of these to expand the capabilities of my four-bay HP Microserver Gen8: http://www.icydock.com/goods.php?id=201. I use it in eSATA mode (though FWIW it also supports USB 3), connected to one of these: https://www.amazon.co.uk/gp/product/B00AZ9T2SW for a 6 Gb/s eSATA connection. The combination works very well and I use the two internal SATA ports for a pair of cache SSDs. The Icy Cube's port multiplier passes SMART status without difficulty, unlike a two-drive StarTech external case I tried.

 

Cheers.  That's the exact card I bought.  The icy dock is a bit outside my budget bug then when it comes to my data it's probably worth staying in one weekend to buy something better.

[John_M]

I agree that the Icy Cube is quite expensive - a second HP Microserver would have cost only a little more! - but it's the only external case I could find that (a) supports 6 Gb/s eSATA and (b) passes SMART data to the host. The other features I like are the built-in power supply and the four disk bays. I would have preferred trayless disk slots, but that's not a big deal and they do lock in very well - a little too well, perhaps! A slight peculiarity is that the wiring between the port multiplier chip and the drive bays doesn't follow a logical order (top to bottom or bottom to top) but, again, that is of no real consequence and unRAID sees all four disks just as though they were attached to four internal SATA ports. It's a great solution and I'd happily buy another if I needed external expansion for another unRAID server

[Derek_]

Old topic, but DuckDuckGo brought me here.

 

Is it still the case that eSATA is preferred over USB with USB3.1/3.2 gen blah blah and USB4 (or whatever stupid name they give it) being 5-10-20 Gb/s depending on which USB is available to you?

 

https://en.wikipedia.org/wiki/USB_3.0#USB_3.2

[testdasi]

2 hours ago, Derek_ said:

Old topic, but DuckDuckGo brought me here.

 

Is it still the case that eSATA is preferred over USB with USB3.1/3.2 gen blah blah and USB4 (or whatever stupid name they give it) being 5-10-20 Gb/s depending on which USB is available to you?

 

https://en.wikipedia.org/wiki/USB_3.0#USB_3.2

Yes. It still is.

USB 3.x still introduces latency. The headline throughput is nice but latency is what kills real life performance.

USB 4.0 is the same with the exception of PCIe / Thunderbolt connection, provided it's PCIe-based storage (e.g. NVMe) with motherboard support.

[Derek_]

Interesting to know. Thanks.