[lug] USB3 vs eSATA III question

stimits at comcast.net stimits at comcast.net
Mon Jul 23 13:37:34 MDT 2018


If you can still access the device on console or ssh check for "dmesg" about the time of the event. If you think video is involved, also check "/var/log/Xorg.0.log". Any backtrace can be useful.
 
----- Original Message -----From: Bear Giles <bgiles at coyotesong.com>To: Boulder (Colorado) Linux Users Group -- General Mailing List <lug at lug.boulder.co.us>Sent: Mon, 23 Jul 2018 14:26:10 -0000 (UTC)Subject: Re: [lug] USB3 vs eSATA III question


My chip drives, for lack of a better term, all show up as /dev/sda except for my new(ish) desktop. It shows up as /dev/nvme0n1p. If it matters the former are NUC-class systems, the latter is a relatively hefty i7 desktop. My laptops are all 2.5" drives.

It's probably related to cost. The NUCs require the chip drives due to space and power limitations, not performance, so the extra cost for an NVMe controller (upfront cost) and compatible chip drive (backend cost) isn't worth it. In contrast anyone paying a premium for a desktop that can handle 64 GB of memory is going to put a premium on performance and the extra cost is justifiable.

The latter does seem to have a few other problems though. I've seen it lock up for minutes at a time with no visible cause when I 1) had a video card installed or 2) had my SSD attached to SATA0. It's working fine with the SSD attached to SATA2. It took a while to figure out it was hardware related. (Sigh - I want to make a warranty claim but I'm sure they're first question will be if it could be the Linux drivers.) I don't know if I would describe as problems related to booting from NVMe though.


On Sun, Jul 22, 2018 at 7:50 PM, Lee Woodworth <blug-mail at duboulder.com> wrote:
I have generally not had trouble booting usb disks with an initrd. External

USB2/3 or sata->USB2/3 enclosures using LVM. It helps to have root=/dev/mapper/....

on the kernel command line, and similar in fstab.

Bios support for gpt partition tables can be a factor for boot disks.

PC Engines APU2 systems detect usb3 external drives, but seabios segfaults

when it encounters a gpt partition table.

AFAIK, pcie m2 ssds can use either SATA or NVMe protocols (M or B keyed I think).

Do older bios versions know about NVMe? We have a Jan 2017 system where the PCI

controller for NVMe shows up as /dev/nvme0 (but not in /sys/class/block) while the connected m2 2280 shows as /dev/nvme0n1 and is an unbootable block device.

/dev/sda is a different m2 2280 using sata and is bootable (motherboard connector).



On 07/22/2018 05:20 PM, Bear Giles wrote:
I have a couple NUCs with that type of drive, plus an NVMe on main desktop.

No problems on any of them.

I just bought several of these:https://www.amazon.com/Lexar-JumpDrive-64GB-Flash-Drive/dp/B00S5V5PEC  I

think I forgot to convert units - reading at 150 MBps is about 1.2 Gbps.

Not as fast as that stick but it's a lot cheaper.

I'll be able to say something about booting from USB soon - one of my

projects before I leave for trip next weekend is installing Ubuntu onto an

external (USB) drive. I've been traveling with two laptops - a bit of a

pain - and decided to try booting from a USB drive instead. My original

thought was a USB stick but I might use a portable drive instead.

On Sun, Jul 22, 2018 at 4:58 PM, Orion Poplawski <orion at nwra.com> wrote:

We have several PCIe sssd laptops running EL7 with no issues.  Great

performance.



On 07/22/2018 12:39 PM, Davide Del Vento wrote:

I don't know anything about your question, but I'm seeing the most

recent/performant (SSD) drives are using PCIe instead of anything

else. I've also heard that booting linux from PCIe can be troublesome,

so I think I'll buy a normal SATA drive (I'm in the market for a small

one).

On Sun, Jul 22, 2018 at 12:27 PM, Bear Giles <bgiles at coyotesong.com>

wrote:

This is mostly from curiousity...

USB 3 has a claimed bandwidth of 3 Gbps.

eSATA II has a claimed bandwidth of 3 Gbps, and eSATA III has a claimed

benefit of 6 Gbps.

I don't think any USB stick is going to be pushing 3 Gbps (but I'm not

100%

certain), but perhaps an external hard drive, esp. an external SSD. But

is

that actually realistic?

In contrast my experience with eSATA is that it really is akin a

traditionally installed disk.

Like I said this is mostly from curiosity. I noticed my recent systems

haven't had eSATA ports but it's easy to add a half-height card for one.

Ditto external drives - they usually only have USB 3 but if you buy an

external drive case for your own drive then it's easy to find them with

both

USB 3 and eSATA. So I have my eSATA gear but it might not be necessary

any

longer if the quoted USB 3 numbers are accurate.

Does anyone else have experience with both USB 3 and eSATA?

(Meanwhile I'm wondering what to do with a few old external drives that

are

USB 2. They're so much slower and smaller than my external USB 3 drives.)

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--

Orion Poplawski

Manager of NWRA Technical Systems          720-772-5637

NWRA, Boulder/CoRA Office             FAX: 303-415-9702

3380 Mitchell Lane                       orion at nwra.com

Boulder, CO 80301                 https://www.nwra.com/

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