On 2016-08-30 12:08, Lindsay Mathieson wrote:
On 30/08/2016 7:57 PM, Carlos E. R. wrote:
But nothing new in this area. Nothing like "debacle over RAID 5/6" that Lindsay mentioned.
Or is he referring to a new implementation of raid? :-? I thought I heard of a raid implementation peculiar to btrfs.
"Btrfs RAID 5/6 Code Found To Be Very Unsafe & Will Likely Require A Rewrite"
http://www.phoronix.com/scan.php?page=news_item&px=Btrfs-RAID-56-Is-Bad
« It turns out the RAID5 and RAID6 code for the Btrfs file-system's built-in RAID support is faulty and users should not be making use of it if you care about your data. » It is "btrfs built-in raid", thus not the traditional Linux software raid implementation.
The btrfs scrub recalculates the wrong parity for raid 5/6 volumes, the bug has existed for years - probably the cause for a recovery failure bug the btrfs team have been trying to track down.
Thanks for this clarification :-) -- Cheers / Saludos, Carlos E. R. (from 13.1 x86_64 "Bottle" at Telcontar)