Can a Raid 1 be shared on a LAN

Not as disks, but only as standard folder sharing for folders on the disks.  RAID is internal to the machine.

Not sure you can really  RAID ext USB drives without applying some hacks to the system.  Windows sees the drives as removable drives and that in itself causes a limiting factor.

What is the desired goal of RAID 1 for external USB drives.  (Backup ?). If so use Backup/Restore feature in Windows 10 or use Robocopy to mirror the data.

robocopy E:\ F:\ /Mir 

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Windows sees the drives as removable drives and that in itself causes a limiting factor.  

Yes.  And in addition the LAN speed would be too slow for RAID to work and synchronize properly.

I read the question as wanting two USB drives attached to a single computer, RAID it, Share it.
I did not know you can RAID over LAN or at a minimum on Windows .

You can share the folders, yes - I agree.

You can get a Buffalo NAS with RAID drives that will likely do what you want.     Buffalo's TeraStation™ 1200

https://www.dell.com/en-ca/shop/buffalo-terastation-1200-2-bay-2tb-raid-network-attached-storage-ts1200d0202/apd/a7970331/storage-drives-media?mkwid=sgLXXevUv&pcrid=232949195922&pkw=&pmt=b&pdv=c&pdv=c&slid=&product=&VEN1=sgLXXevUv,232949195922,901mtv7630,c,,&VEN1=sgLXXevUv,232949195922,901mtv7630,c,,&VEN2=b,&VEN2=b,&cid=3852&cid=3852&lid=5733920&lid=5733920&dgc=st&dgc=st&dgseg=dhs&dgseg=dhs&acd=123088137920560&acd=123088137920560&st=&gclid=EAIaIQobChMIlI6_xJrB4AIVgbjACh3uxA2vEAAYASAAEgJsxvD_BwE&VEN3=811804722331734628

If we are suggesting alternatives here is Western Digital solution:
USB with built-in RAID
https://www.wd.com/products/external-storage/my-book-duo.html#WDBFBE0040JBK-NESN 

NAS solution.
https://www.wd.com/products/network-attached-storage/my-cloud-pr4100.html

A lot of good information. Thank you. But I should have been more specific and clearer in my question.

I have two G-Tech EXTERNAL HDs. I can make them a Raid 1 (mostly for backup). Can I share that particular Raid with someone else on my LAN (read only). The machine will treat the two HDs in the Raid as one volume, yes?

As mentioned removable drives cannot be configured in a RAID.  That in its self is a limitation.

If you are looking for a redundant backup you are better off coming up with a validated backup solution.  

RAID is not a backup solution.

The machine will treat the two HDs in the Raid as one volume, yes?  <-- That would be a function of your machine drive controller, but running them either USB connected or Ethernet connected will be too slow. So you would need an additional Drive Controller for the two external drives.

Can I share that particular Raid with someone else on my LAN (read only).   <-- No, I do not think so unless it has its own external controller.  

And then "sharing" means folder sharing.

Two computers cannot share the same RAID set with one controller.

@john:

Two computers cannot share the same RAID set with one controller.

I disagree, it can be done if the right file systems are used and the computer use an interlocking scheme.
OpenVMS has done tis for 35 years? (OpenVMS Clusters share anything including disks, weather those a re RAID in SANs or local disks shared together on the network),
On Linux there is GFS.   Some network based filsystem use this "kind of technology" under the hood.
To some extend VMWare has provisions for this.

it can be done if the right file systems are used and the computer use an interlocking scheme.

I was thinking of the more ordinary setup here.

I was thinking of the more ordinary setup here.

Here's my "ordinary," which I think is overkill, and ignores the NAS, which I just use as storage for a lot of data, instead of a "working" device where I can read and write files. (I'm assuming that the ethernet NAS does not post the danger of corruption that working off a USB device does.

-Work off a folder on server
-Using Second Copy, back that folder up to an EXT HD (Y:)
-Copy  Y: backup to another Ext HD (W:) as insurance.

I'm a writer, so I'm protecting a rather large manuscript-in-progress.

Just use a single USB Backup Hard Drive for what you want. We use these at clients.

For your desired goal I think creating a share of the USB just like creating any other share off the W10 machine and schedule a robocopy to run at your desired interval to copy any new data to the other drive.

creating a share of the USB

By which I assume you mean, simply share the EXT HD?

Thanks to all.