[OpenIndiana-discuss] zfs and usb drives

[James Carlson]

On 05/31/12 14:08, Jay Heyl wrote:
> That's excellent information. I'm sure you've saved me some future grief.
> Thanks.

I have a slightly different story.

I had a Sun X4600 (x64) server running OpenSolaris.  I was converting
over from an older system and tried to mirror an external USB drive onto
an internal SAS disk using ZFS resilvering as a way to transfer the
data.  The plan was to get it copied, then detach the USB drive, and
then mirror internally.

Big mistake.  The system quickly ground to a halt while doing the
initial resilver operation (copying from the USB drive to the internal
SAS one).

After cleaning up the mess, I was able to import the external USB device
as stand-alone disk pool with ZFS, and then use "zfs send" and "zfs
recv" to copy things over.

Something about mirroring between a very fast internal disk and a very
slow external one was a Bad Thing.

It's entirely possible that the USB drivers have improved greatly since
circa 2009, and that this is just "old news," but I'm gunshy now.  I
don't think I'd even attempt to use USB for an external file system,
except possibly as a backup mechanism.

Your mileage will vary.

-- 
James Carlson         42.703N 71.076W         <carlsonj at workingcode.com>