is this RAID configuration possible?

[Alex Gio]

Total noob to RAID here.

I was wondering if it's possible to have (a hypothetical) 2 500gb ssdrives in a RAID0 type configuration, but then have a 3rd 1TB drive that backs them up similar to a RAID 1?

[emosun]

Yea , you'd just use backup software instead to backup the seemly single ssd raid 0 configuration

[Windows7ge]

That's very doable. You can use something like Windows Storage Spaces to create the two drive RAID0 then something like FreeFileSync to backup that array to the 1TB HDD.

[Nick7]

Well, you can either do RAID0 over two smaller drives, and backup to second.. OR you can make it all RAID.

 

On Linux you'd use mdadm to create raid.

First, create RAID0 over two smaller drives, and than use that mdadm device created along with larger drive to create RAID1.

 

If smaller disks are /dev/sdb /dev/sdc and larger is /dev/sdd, you'd usually first create on each disk partition which covers whole disk.

Than issue following commands:

# mdadm --create /dev/md0 --run --level=0 --raid-devices=2 /dev/sdb1 /dev/sdc1

# mdadm --create /dev/md1 --run --level=1 --raid-devices=2 /dev/md0 /dev/sdd1

 

Now you'll have device '/dev/md1'. On top of that one create whatever you want - LVM, direct filesystem, etc... just keep in mind upon reboot /dev/md1 name might change, so use UUID's.

 

You can also just create stripe device of two smaller ones and use them with ZFS, and create mirror within ZFS.

Depends what you want...

For ZFS option you'd do:

# mdadm --create /dev/md0 --run --level=0 --raid-devices=2 /dev/sdb1 /dev/sdc1

# zpool create mypool mirror /dev/md0 /dev/sdd1

 

Also for later one (ZFS) you need to make sure mdadm device is scanned before ZFS is in boot process... so might be a little more fiddly.

 

But yes, it's possible.