Note that if you had dual parity (which would, of course, require another 8TB parity drive) you could then, in theory, do 2 at once; but I still wouldn't recommend it.  [Probably the most important advantage of dual parity is that you're not "running at risk" when a drive fails and you're rebuilding it with a replacement.  If you intentionally fail 2 drives, then you just lost that advantage.]

 

I believe a dual disk upgrade is one of the advantages of dual parity, done some myself, I don't use the server during the rebuild so if anything goes wrong I can always use the old disks with a new config and trust parity.

 

Wouldn't do it if had to do new writes during the rebuild or one of the disks was bad, i.e., replacing a bad disk while upgrading another at the same time.

Note that if you had dual parity (which would, of course, require another 8TB parity drive) you could then, in theory, do 2 at once; but I still wouldn't recommend it.  [Probably the most important advantage of dual parity is that you're not "running at risk" when a drive fails and you're rebuilding it with a replacement.  If you intentionally fail 2 drives, then you just lost that advantage.]

 

I believe a dual disk upgrade is one of the advantages of dual parity, done some myself, I don't use the server during the rebuild so if anything goes wrong I can always use the old disks with a new config and trust parity.

 

Wouldn't do it if had to do new writes during the rebuild or one of the disks was bad, i.e., replacing a bad disk while upgrading another at the same time.

 

Just depends on whether or not you're willing to run at risk.  Clearly it's no worse than doing a single disk upgrade with single parity -- and I agree that if you still have the old disks intact and don't do any activity on the server, it's not really a "risk", since you could always do a New Config w/Trust Parity to get back to exactly where you started.

 

I'm sorry, I have another question please.

I have a second backup USB flash drive, also with 6.2.0-rc3. I keep both USB's updated. I decided to start the server with the second one, it is not recognizing the new drives. I'm guessing I need to copy the contents over from the first USB drive?

 

NO !!!  Don't boot with a different flash drive.    There's really no reason to do this unless you primary flash should fail.  In that case, you simply need to boot to a new flash drive with a clean install of UnRAID; copy your UnRAID key file for the original (failed) flash drive to the new flash drive;  boot to the new flash; assign the drives; and update your key to the new drive [The key update process is built in to UnRAID now].    There are two things you should be sure you have safely backed up:  (a)  your key file; and (b) the current config (I'd just keep a screenshot of the Web GUI showing the disk assignments).

 

... Note that while it's possible to keep two flash drives "synced" if you have separate keys for each of them; I'm NOT sure if there are additional complications with the 6.2 RC's, as these "phone home" during a reboot to do a validation of the key and confirm that the RC in use doesn't have any known serious issues.    This will no longer be the case once 6.2 is officially released.    But the simple fact is there's no need to try and maintain duplicates.

 

... Note that while it's possible to keep two flash drives "synced" if you have separate keys for each of them; I'm NOT sure if there are additional complications with the 6.2 RC's, as these "phone home" during a reboot to do a validation of the key and confirm that the RC in use doesn't have any known serious issues.    This will no longer be the case once 6.2 is officially released.    But the simple fact is there's no need to try and maintain duplicates.

 

Maybe things have changed a bit since I bought my Plus license back in 2010. It was then recommended to buy (2) incase one ever failed. They each have their own key or ID that won't work on any other flash drive. I've been updating each one with each new version of unRAID and booting from each to make sure they both work, and they both always have, including the latest beta 6.2. But, in all that time I have never changed or upgraded my drives??

So, I don't need the other one any more?

... Note that while it's possible to keep two flash drives "synced" if you have separate keys for each of them; I'm NOT sure if there are additional complications with the 6.2 RC's, as these "phone home" during a reboot to do a validation of the key and confirm that the RC in use doesn't have any known serious issues.    This will no longer be the case once 6.2 is officially released.    But the simple fact is there's no need to try and maintain duplicates.

 

Maybe things have changed a bit since I bought my Plus license back in 2010. It was then recommended to buy (2) incase one ever failed. They each have there own key or ID that won't work on any other flash drive. I've been updating each one with each new version and booting from each to make sure they both work, and they both always have, including the latest beta 6.2. But, in all that time I have never changed or upgraded my drives.

So, I don't need the other one any more?

Its not that what you're doing is wrong, but the big problem with it is that you have to be religious about keeping them in sync.  And that means syncing them again when ever drives change.

 

Consider this scenario:

 

You decide to expand the array.  It was composed of all 3tb hard drives, but you grab a 4tb.  Now the 4tb can't be used as a data drive (because its smaller than the current parity drive), so you set it as the new parity drive, and repurpose the original 3tb parity drive as a data drive.

 

If you don't sync the 2 usb's at that time, then if the first one dies, and you start using the second one, you're going to wind up trashing all of the data on the 3tb (now a data drive) because the 2nd stick thinks that it is supposed to be the parity drive, and has no clue about the 4tb.

 

Starting with 6.0, the replacements of USB keys became a more automated procedure (5.x you would have had to email limetech to transfer the key to a new USB).  Now, all you have to do is keep a copy of the .key file and if/when the USB stick dies, move that .key file over to a new USB stick, and unRaid will automatically transfer the registration over to the new stick.  All in a matter of seconds.

 

But, like I said there is no problems with keeping a complete backup fully registered stick ready to go, as long as you back it up whenever the hardware changes.  Short of that, you should delete the config/super.dat file on the backup stick so that the scenario above cannot happen (although you will have to set up the disk assignments again when you use the stick)

 

That, and new utilities (such as CA's appdata backup) include the ability to backup the flash drive to any location you choose (and automatically delete the super.dat file to prevent the scenario above) and record the disk assignments in a text file for easy viewing.

I also bought a 2-pack long ago, and have recommended others do the same.

 

However, Limetech has always been very good at providing free replacement keys for failed flash drives -- and starting with v6 have formalized this policy ... you can get one replacement per year, and the process is actually built into UnRAID.    If your flash drive fails, you just load UnRAID on a new flash drive, and put a copy of your old key on it;  then boot; and you can then do the key replacement online and it will provide a replacement key tied to the new flash drive.

 

So ... you don't need your 2nd key for THAT server.  But it's a perfectly good key that you can use for a 2nd server ... a backup server;  a server for a different purpose; etc.

 

Wow, I didn't know about those changes. I've been away from the forums too long. The system OS has worked so well for the last 6 years. I just power it up and it always works!

 

Thanks everyone!

Just so that people do not think they can dishonestly get a "free" 2nd Unraid license by applying for a replacement license on a new flash drive but keep using the old flash drive, the ID of the replaced flash drive is added to a blacklist built into Unraid which will be in any subsequent releases of Unraid issued after the replacement to prevent the license on the replaced flash from working.

 

I too am glad that I took advantage of the discounted 2-pack license that Limetech used to sell before they had developed the current online replacement mechanism.  And the special offer they had during the Verizon 5 beta period to get a duplicate license of an exisitling one for only $30 was really great value ... But that was a limited time offer during the v5 beta period only.

I successfully synced my second flash drive, they both work identical now. At this point I don't plan on building a second server, so my second flash drive is used solely as a fast backup incase one fails. If one fails I will use the online function to move my license to a new one. But, in the mean time I have a instant backup.

 

Thanks!

I successfully synced my second flash drive, they both work identical now. At this point I don't plan on building a second server, so my second flash drive is used solely as a fast backup incase one fails. If one fails I will use the online function to move my license to a new one. But, in the mean time I have a instant backup.

 

Thanks!

 

FWIW, a new flash drive is just about as "instant".    Downloading the latest UnRAID release (1-2 min);  extracting it onto a new flash drive and running MakeBootable (2-3 min); copying your key file to it (30 seconds); and then booting is all it takes to use a new drive.    Perhaps ten minutes total.    But it certainly doesn't hurt to have a "live spare" that you can also boot from -- just be CERTAIN that you keep everything absolutely synchronized, or you could cause some real havoc with the server if you boot with the wrong unit.

 

I successfully synced my second flash drive, they both work identical now. At this point I don't plan on building a second server, so my second flash drive is used solely as a fast backup incase one fails. If one fails I will use the online function to move my license to a new one. But, in the mean time I have a instant backup.

 

Thanks!

 

FWIW, a new flash drive is just about as "instant".    Downloading the latest UnRAID release (1-2 min);  extracting it onto a new flash drive and running MakeBootable (2-3 min); copying your key file to it (30 seconds); and then booting is all it takes to use a new drive.    Perhaps ten minutes total.    But it certainly doesn't hurt to have a "live spare" that you can also boot from -- just be CERTAIN that you keep everything absolutely synchronized, or you could cause some real havoc with the server if you boot with the wrong unit.

 

Sounds good, I'll definitely move the license if I fail one. I don't think these fail too often though? At least I don't hear about it.

My config is cloned on my spare also, but this is also kept on my PC

Flash drives don't fail very often.  At work I'm running a few FreeNAS boxes on really, really cheap and nasty "Integral" branded USB sticks, and they've been working for 6-7 years now.  No issues at all.