Hi,

 

I'm a long time Unraid user, but have only since v6 have started using a btrfs cache disk. I added it purely because of the docker and VM support, which is so awesome. I added a 240GB Patriot Blaze I had previously purchased for use in an USB enclosure. It worked fine, although no temperature sensor annoyed me, plus I missed a fast external in my laptop bag

 

I decided a couple of weeks ago that I should add redundancy, so I purchased a nice Samsumg 850 Pro 250GB. Installed it, let Unraid format it and create a cache pool; everything seemed fine. I pretty much treated it the same way I have when adding a disk to the Array each time, over many years. Add the new disk to a new slot, confirm and start the array.

 

Then last weekend I decided to replace that Patriot Blaze with another Samsung 850 Pro, and get my Blaze back into the laptop bag. Rather than reading through the forums as I should, I rushed into it. I pulled the Patriot and swapped in the new 850, and restarted the server. After starting the array I thought it would rebuild onto the new disk automatically... however no - empty cache share. Oops but no worries - I still have the old disk. I shutdown again, put the old disk back, restarted the server and array... and I guess it formatted the old disk because, still no cache data.

 

At the time I was a bit disappointed in myself, but hey, it's only server configs. I rebuilt them in a few hours, and the docker configs being safely stored on the flash was really helpful. No big deal.

 

So, on reading through the forums after the fact, I see that I should have been running a 'balance'. When should I have run that? If it's so important that it's run, wouldn't it be better if Unraid just run it for me, like the 'rebuilding' process for the Array?

 

Thanks

James

Hi,

 

I'm a long time Unraid user, but have only since v6 have started using a btrfs cache disk. I added it purely because of the docker and VM support, which is so awesome. I added a 240GB Patriot Blaze I had previously purchased for use in an USB enclosure. It worked fine, although no temperature sensor annoyed me, plus I missed a fast external in my laptop bag

 

I decided a couple of weeks ago that I should add redundancy, so I purchased a nice Samsumg 850 Pro 250GB. Installed it, let Unraid format it and create a cache pool; everything seemed fine. I pretty much treated it the same way I have when adding a disk to the Array each time, over many years. Add the new disk to a new slot, confirm and start the array.

 

Then last weekend I decided to replace that Patriot Blaze with another Samsung 850 Pro, and get my Blaze back into the laptop bag. Rather than reading through the forums as I should, I rushed into it. I pulled the Patriot and swapped in the new 850, and restarted the server. After starting the array I thought it would rebuild onto the new disk automatically... however no - empty cache share. Oops but no worries - I still have the old disk. I shutdown again, put the old disk back, restarted the server and array... and I guess it formatted the old disk because, still no cache data.

 

At the time I was a bit disappointed in myself, but hey, it's only server configs. I rebuilt them in a few hours, and the docker configs being safely stored on the flash was really helpful. No big deal.

 

So, on reading through the forums after the fact, I see that I should have been running a 'balance'. When should I have run that? If it's so important that it's run, wouldn't it be better if Unraid just run it for me, like the 'rebuilding' process for the Array?

 

Thanks

James

 

I think this is a good question. Part of the issue is that you can balance in a lot of different ways, Raid 1 2 disk, Raid 1 4 disk, Raid 0 2 disk, Raid 0 3 disk, etc, etc, etc.

 

Now officially I think Limetech only supports Raid 1 with 2-X Disks, but I think the major problem is how do they handle all the other options that can exist.

 

I think at minimum it should prompt you on if you want to balance whenever it notices the cache pool has changed.

I decided a couple of weeks ago that I should add redundancy, so I purchased a nice Samsumg 850 Pro 250GB. Installed it, let Unraid format it and create a cache pool; everything seemed fine. I pretty much treated it the same way I have when adding a disk to the Array each time, over many years. Add the new disk to a new slot, confirm and start the array.

 

This is the normal procedure, if it didn't work something went wrong during the replacement.