Re: "delete missing" with two missing devices doesn't delete both missing, only does a partial reconstruction

[Anand Jain <anand.jain@oracle.com>]

 > BTW, when this is all over with, how do I make sure there are really
 > two copies of everything?  Will a scrub verify this?  Should I run a
 > balance operation?

pls use 'btrfs bal profile and convert' to migrate single chunk (if any 
created when there were lesser number of RW-able devices) back to your 
desired raid1. Do this when all the devices are back online. Kindly note 
there is a bug in the btrfs VM that you won't be able to bring a device 
online with out unmount -> mount (I am working to fix). btrfs-progs will 
be wrong in this case don't depend too much on that.
So to understand inside of btrfs kernel volume I generally use:
     https://patchwork.kernel.org/patch/5816011/

In there if bdev is null it indicates device is scanned but not part of 
VM yet. Then unmount -> mount will bring device back to be part of VM.

 >> After applying Anand's patch, I was able to mount my 4-drive RAID1
 >> and bring a new fourth drive online.

 >> However, something weird happened
 >> where the first "delete missing" only deleted one missing drive and
 >> only did a partial duplication.  I've posted a bug report here:

that seems to be normal to me. unless I am missing something else / clarity.


Thanks, Anand