Re: ENOSPC errors during raid1 rebalance

[Michael Russo <mike@papersolve.com>]

Hugo Mills <hugo <at> carfax.org.uk> writes:

>    This is just a guess, but you might have some large (>1GB) 
extents
> in there that span across multiple chunks. I'd suggest running a 
btrfs
> defrag on any particularly big files and see if that helps the 
situation.
> 

Doing this is definitely helping, but I have to run the defrag multiple 
times with different values for "-t". If I don't include -t the defrag 
runs really quickly but doesn't seem to do anything.  Now I've gotten 
it down to only 2 5GB segments that won't move.  I'm going to 
extract the very big log generated when I run 
"btrfs ba start -dconvert=raid1,soft /mymedia" 
with enospc_debug and send it as a file, hopefully it will help.  
The first couple lines are:

Mar  4 10:49:23 ossy kernel: [134922.806764] BTRFS info (device sdd1): 
relocating block group 894460493824 flags 1
Mar  4 10:49:32 ossy kernel: [134931.650504] BTRFS error (device sdd1): 
allocation failed flags 17, wanted 1368420352
Mar  4 10:49:32 ossy kernel: [134931.650507] BTRFS: space_info 1 has 
113996488704 free, is not full
Mar  4 10:49:32 ossy kernel: [134931.650509] BTRFS: space_info 
total=1320702443520, used=1201311391744, pinned=0, 
reserved=565596160, may_use=1368420352, readonly=4828966912