Still running 4.7. I'd like to start building a 5.0 environment on a separate flash drive, and have the ability to go back and forth between releases.  Is copying super.dat when switching flash drives all that's necessary?

 

I seem to remember that Tom said that it wasn’t a problem going back to 4.7 after newperms has been run.

Do you have two keys?

... as I assume you know, your UnRAID key is tied to a specific flash drive.

 

Got 2 keys when I bought my license.

Then all you need to do is set up a config on each one, and just select which one to boot from via your BIOS boot menu each time you want to switch.

 

Then all you need to do is set up a config on each one, and just select which one to boot from via your BIOS boot menu each time you want to switch.

No, not quite that easy.    They BOTH must be labeled UNRAID, and only one UNRAID labeled volume must exist.

 

The trick is to unplug one flash drive and plug in the other while powered down (or at least AFTER you've stopped the array, but before rebooting.)

Joe's right of course.  I forgot about the conflicting labels you'd have if you didn't unplug one of the drives 

... actually makes it simpler, however, since you don't have to change anything vis-à-vis the boot device.    Just shut down; swap the flash drives; and turn the system back on 

 

... actually makes it simpler, however, since you don't have to change anything vis-à-vis the boot device.    Just shut down; swap the flash drives; and turn the system back on 

Well, you might need to select the alternate flash drive to boot from. 

Since the first flash drive would be missing (since you unplugged it) many BIOS will then default to booting from the first hard disk installed.  It would not likely to automatically boot from the alternate flash drive.

 

Joe L. 

Possibly.  But if a USB flash device is plugged into the same USB port that it was set to default from, I think it's likely it will just boot from there.  Most of my system behave that way ... but I know not all do.

 

But the real question is:

 

If you have a flash drive with a fully functional 4.7, labeled UNRAID, license key, disks configured, shares set up, etc.

 

And a flash with a fully functional 5.x,labeled UNRAID,  license key, disks configured, shares set up, etc.

 

Can you shutdown a server under one OS, pull the flash, copy super.dat to the other flash, insert the other flash, and bring up the server under the other OS.

 

The goal is that both OS's are happy, no irregularities, and no rebuilding of the raid drive required under either OS. Is the super.dat file the only thing that needs to change when switching flash drives?

 

I would like to be able to switch back and forth several times before committing to 5.x, with minimal impact.

But the real question is:

 

If you have a flash drive with a fully functional 4.7, labeled UNRAID, license key, disks configured, shares set up, etc.

 

And a flash with a fully functional 5.x,labeled UNRAID,  license key, disks configured, shares set up, etc.

 

Can you shutdown a server under one OS, pull the flash, copy super.dat to the other flash, insert the other flash, and bring up the server under the other OS.

 

The goal is that both OS's are happy, no irregularities, and no rebuilding of the raid drive required under either OS. Is the super.dat file the only thing that needs to change when switching flash drives?

 

I would like to be able to switch back and forth several times before committing to 5.x, with minimal impact.

I know the super.dat format is not exactly identical between 4.7 and 5.X.

 

I have a 4.7 system and a 5.0rc15a system.  The md_private.h file in them describes the super.dat file.

 

They are "mostly" the same, but the trailing portion of the 5.X file has an array of structures for 24 data disks.  The trailing portion of the 4.7 file has an array of structures for 21 disks.

 

You might be able to get away with it, since obviously anyone upgrading must have the smaller 21 disk super.dat.  And it must end up as a 24 disk super.dat somehow.

 

However, I'd be careful.  Save copies of the super.dat files with the array stopped as insurance.

 

Joe L.

 

 

Thanks

Joe knows more about this than I do;  but I'd think that a more likely area of confusion would be the security descriptors IF you're using user accounts.    I just run my systems "wide open" -- if you're on my network, you can use my UnRAID systems;  but I know the security model changed somewhat between v4 and v5.

 

Switching from 5 to 4 is easy. Switching from 4 to 5 requires the New Permissions script to be run every time.

Switching from 5 to 4 is easy. Switching from 4 to 5 requires the New Permissions script to be run every time.

 

Sounds like the best approach is to just switch to 5 and stay there