I have two SSD's that are setup as my cache drives. 

One has 240GB, the other 480GB. My understanding is that the cache drive will have a maximum of 480GB (double of the smalles drive).

Right now, it is only providing 120GB of space.

 

I tried to balance and rebuild the raid without success.

 

Here's the status of the btrfs:

Data, RAID0: total=119.10GiB, used=117.84GiB Data,

single: total=100.00GiB, used=96.56GiB System,

single: total=4.00MiB, used=48.00KiB Metadata,

single: total=1.01GiB, used=231.70MiB GlobalReserve,

single: total=167.67MiB, used=0.00B

 

The UI says it has 490GB of available space, but it's wrong. I had my VM's paused multiple times when I tried to add a 20GB file.

The real used space is 200GB.

 

Any tips?

Edited October 24, 20205 yr by Márcio Lima

The default is RAID1 which means the available space is equal to the SMALLER of 2 dissimilar size disks. It is a known issue that when the disks are of different sizes that BTRFS tends to report space incorrectly.

I converted it into RAID 0. The smallest one has 240GB.

You should convert it to "single"

 

Would you please clarify why? I would like to keep the RAID 0 for performance reasons.

Single would give maximum capacity, but according to FAQ raid0 should work as you say. Maybe you have something wrong with the configuration.

 

Go to Tools - Diagnostics and attach the complete Diagnostics ZIP file to your NEXT post in this thread. Maybe @JorgeB will know what is wrong.

There you go.

 

I will be changing the smallest cache disk with other 2 of the same size, but I'll keep the current configuration for at least a month.

ultimatemachine-diagnostics-20201025-0714.zip

Pool has dual data profiles, single and raid0:

 

             Data      Data      Metadata  System              
Id Path      single    RAID0     single    single   Unallocated
-- --------- --------- --------- --------- -------- -----------
 1 /dev/sdb1 100.00GiB  60.55GiB   1.01GiB  4.00MiB    62.01GiB
 2 /dev/sdd1         -  60.55GiB         -        -   386.58GiB

 

Run balance to raid0 again.

I did that, but it kept the two profiles.

Please post diags after balance attempt.

Thanks everyone for the help, but I ended up removing the 240GB out of frustration for now. I'll buy another 480GB SSD.