Should I be Scrubbing and Balancing BTRFS NVMe Cache pool?

[adminmat]

I'm running two NVMe drives (BTRFS) in RAID1 for my main Cache pool. I just came across the option to schedule "Balance" and "Scrub". Is this something I should be doing regularly? I've not used this before. Searching for this answers provides wildly varying opinions. 

 

 

[JorgeB]

Scrub should be done once a month and after any unclean shutdown, balance is not so easy to explain, but as long as you don't keep the pool always almost full or have a lot of small changing blocks regular balance is usually not needed, but it won't hurt, except for the extra flash wear.

[darthkielbasa]

Scrub should be done once a month and after any unclean shutdown, balance is not so easy to explain, but as long as you don't keep the pool always almost full or have a lot of small changing blocks regular balance is usually not needed, but it won't hurt, except for the extra flash wear.

I was chasing disk errors that were spamming my logs for quite a while and stumbled across Scrubbing. The correlation between unclean shutdowns and my numerous disk errors did not register between my ears. Plus, I had a disk fail during the dark phase of this journey.

I chalk it up to being a a newer unraid user, unfamiliar with Linux, unfamiliar with btrfs, and with NAS practices in general.

Pain is an opportunity for growth.


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[tuner562]

Why isn't this caught by Fix Common Problems? If scrubbing is supposed be scheduled this should be checked to see if it is scheduled or not. Mine was disabled for whatever reason.

[sunwind]

On 7/17/2024 at 1:07 AM, tuner562 said:

Why isn't this caught by Fix Common Problems? If scrubbing is supposed be scheduled this should be checked to see if it is scheduled or not. Mine was disabled for whatever reason.

My array is BTFRS. and not XFS.

Should I scrub all the drives once per month at the same time, or stagger each one (About 8 drives) by about 12 hours? Does it matter?

 

As for cache, and pools, they re small and take only a couple hours So I'll set them to run on the same day of the month as the first disk in the array.

 

This is disk 1 of my array:

 

Recommended monthly. Do I set the same thing up for balances on everything except schedule them for the day after the scrubbing in the month, or should the scrubbing be done before?

Or just leave all disabled?