Mirrored boot disks--Installation vs. Post-Installation mirroring

[zeroluck]

Is there a functional difference between installing to two devices (in my case USB keys) at once during the install process vs installing to one and adding a mirror later from the GUI?

The reason I ask is I had some devices fail and I'm wondering if that makes a difference because I wasn't able to recover anything or boot from the mirrored disk. I used the install on one disk then add a mirror method.

 

[MMacD]

Did the copy from the initial thumb to the added one run to completion? I.e., did you actually have a mirror, or just a thumb that was in the process of being made one?

It certainly shouldn't matter which method you use, since mirroring doesn't (or at least shouldn't) do anything fancy with the storage, and adding a new unit is exactly what you have to do when one fails. So if the system didn't finish the copy then you really didn't have a mirror. And if it didn't even start the copy after you declared the mirror, then there's a bug.

 

[dlavigne]

It shouldn't be different, but you may have been bitten by https://forums.freenas.org/index.php?threads/replace-usb-sticks-error-grub.40620/#post-257709.

 

[zeroluck]

Did the copy from the initial thumb to the added one run to completion? I.e., did you actually have a mirror, or just a thumb that was in the process of being made one?

It certainly shouldn't matter which method you use, since mirroring doesn't (or at least shouldn't) do anything fancy with the storage, and adding a new unit is exactly what you have to do when one fails. So if the system didn't finish the copy then you really didn't have a mirror. And if it didn't even start the copy after you declared the mirror, then there's a bug.

The mirror definitely finished. It took a while for the mirror to copy over but I saw that both mirrors were online in the GUI.

 

[zeroluck]

It shouldn't be different, but you may have been bitten by https://forums.freenas.org/index.php?threads/replace-usb-sticks-error-grub.40620/#post-257709.

That was going to be my next question. With the zfs mirroring, should both drives be individually bootable by themselves? I was on a very recent version of FreeNAS 9.3.

 

[dlavigne]

With the zfs mirroring, should both drives be individually bootable by themselves? I was on a very recent version of FreeNAS 9.3.

Yes. I'm assuming that referenced bug wasn't fixed. Since the person I originally asked hasn't responded yet, can you open a new ticket at bugs.freenas.org, mention the old bug # and how it's still not working, and post the new bug number here.

 

[dlavigne]

And I spoke too soon: https://forums.freenas.org/index.php?threads/replace-usb-sticks-error-grub.40620/#post-258228.