[SOLVED] Cache Pool Difficulties

[MacP]

Hey All,

 

Firstly let me just say, you all rock and thanks taking the time to help me with this issue.

 

I had a 2 drive ssd cache pool in raid 1, one of my drives was reporting that it was reaching EOL so I got a replacement. Being somewhat new to this process (I have never had to replace a cache drive yet) I followed some instructions on the forum that suggested I add the replacement drive to the pool before removing the failing drive. I ran a preclear and when the drive reported that all was good I added it to the drive pool. to my surprise though it increased the capacity of my cache pool. I have tried several terminal commands to remove the offending drive from my cache pool but I get either "argument invalid" or "error not a block device"

 

I have attached the diagnostic of the btrfs usage but I have pulled a full set of diagnostic documents if anyone needs more info.

 

All I want to do is return to a 2 drive raid 1 if thats possible. I have regular backups of the app data that lives on the cache so if I have to rebuild from scratch Im pretty sure I can do that but Im hoping that I can just remove the drive without resorting to that. The drive that needs replacing is effectively empty at the moment as all the data has been moved to the replacement drive. 

 

Thanks again for you wisdom

 

Mac

btrfs-usage.txt

Edited July 29, 2020 by MacP

[Lindworm]

Hi, you will not increase the cache pool size as its a mirrored pool not a raid. 

What I would do, is to take only one cache drive (the largest). To make the conversion easy (and probably encrypt the cache drive).

- rsync all cache data to a folder on your raid

- stop the array

- goto tools --> new config

- preserve all but cache and make a new config (check it double you could kill your raid!)

- then goto main, add the cache drive you want

- click on the device name and set up the cache as you like (encrypted/unencrypted and so on)

- start the array

- sometimes it asks you to format the cache drive

- replay the cache data to /mnt/cache

be happy 🙂

 

(I belive having an rsync cron job copying all cache data every night to the array into a backup folder is best practice)

 

Edited July 29, 2020 by Lindworm

[JorgeB]

10 hours ago, MacP said:

All I want to do is return to a 2 drive raid 1 if thats possible.

It is, just remove one of the devices, see here.

[MacP]

Thank you very much for your advice. I have succeeded in removing the drive and it was all thanks to you!

 

Mac