[SOLVED] Removing 1 Cache drive from a 2 drive Mirror


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14 hours ago, JorgeB said:

If you have the space you can convert back to raid1 and then remove a device, both procedures are in the FAQ pinned on this sub-forum.

My system is doing some strange stuff. my cache array is now showing 250gb instead of 500gb. I tried to convert to raid 1, but its doing nothing. I trying a full balance now, then will try to convert to raid 1.

 

I tried following the guide before and when I removed the cache drive, it would not let me start the array since there was not a 2nd cache disk assigned.

 

My cache is showing as:
Data, DUP: total=165.00GiB, used=164.59GiB

System, DUP: total=32.00MiB, used=48.00KiB

Metadata, DUP: total=1.00GiB, used=615.00MiB

GlobalReserve, single: total=224.03MiB, used=0.00B

 

Edited by Spikerman
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Cache is currently a single device, so it can't be converted to raid1:

 

             Data      Metadata  System              
Id Path      DUP       DUP       DUP      Unallocated
-- --------- --------- --------- -------- -----------
 1 /dev/sdb1 328.00GiB   2.00GiB 64.00MiB   135.70GiB
-- --------- --------- --------- -------- -----------
   Total     164.00GiB   1.00GiB 32.00MiB   135.70GiB
   Used      163.59GiB 616.27MiB 48.00KiB     

For some reason you are using the DUP profile for data, convert to single.

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When I try to convert to single mode, I get this error in console:

Quote

Dec 12 07:26:14 Tower ool www[23487]: /usr/local/emhttp/plugins/dynamix/scripts/btrfs_balance 'start' '/mnt/cache' '-dconvert=single -mconvert=raid1'

Dec 12 07:26:14 Tower kernel: BTRFS error (device sdb1): balance: invalid convert metadata profile raid1

 

Edited by Spikerman
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ran the command and now cache is showing as

Quote

 

Data, single: total=164.00GiB, used=163.59GiB

System, DUP: total=32.00MiB, used=48.00KiB

Metadata, DUP: total=2.00GiB, used=617.25MiB

GlobalReserve, single: total=226.34MiB, used=0.00B

 

I am following your faq post @JorgeB on the process.

Quote

 

Procedure:

 

stop the array

unassign pool disk to remove

it's OK to reorder remaining pool members if you want (but see point below), i.e., you had a three device pool and removed cache2, you can assign cache3 to slot2 before starting the array (you can also do it later)

while it's OK to reorder members it's currently not OK to change the number of cache slots at the same time you remove a device, you can do that after the pool is balance down, i.e., just don't do both things at the same time.

start the array

a balance and/or a device delete will begin depending on the profile used and number of pool members remaining, wait for cache activity to stop, the stop array button will be inhibited during the operation, this can take some time depending on how much data is on the pool and how fast your devices are.

when the cache activity stops or the stop array button is available the replacement is done.

 

I'm trying to remove the 2nd cache drive, but when I set it as unassigned I cannot start the array to perform the balance down.

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  • JorgeB changed the title to [SOLVED] Removing 1 Cache drive from a 2 drive Mirror

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