Resent since google inbox is still not doing clear-text emails...
On Wed, Oct 11, 2017 at 2:09 PM, Jeff Mahoney <jeffm@xxxxxxxx> wrote:
> On 10/11/17 12:41 PM, Ian Kumlien wrote:
[--8<---]
>> Eventually the filesystem becomes read-only and everything is odd...
>
> Are you still able to mount it? I'd be surprised if you could if check
> can't open the file system.
Nope, it's like there never was a filesystem in the first place...
But since metadata should be duplicated all over, i'd assume that it
would be able to mount it and survive.... =)
>> Trying to run btrfs check on the disks results in:
>> btrfs check -b /dev/disk/by-uuid/8d431da9-dad4-481c-a5ad-5e6844f31da0
>> bytenr mismatch, want=912228352, have=0
>> Couldn't read tree root
>> ERROR: cannot open file system
>>
>> (For backup and normal)
>>
>> So even if the data is duplicated on all disks, something in the above
>> errors seemed to cause it to abort
>> (These disks are seagate sshd disks, never ever buying them again)
>
> If you have metadata: dup, that doesn't mean the metadata is duplicated
> on every disk. It means that there are two copies of the metadata on a
> single disk. If that disk is going bad and returning failures for both
> copies of the metadata, you may be out of luck. It's really intended
> for single spinning disks to get a little bit more resiliency in the
> face of bad sectors.
Oh? it looks like it would be 2 per 1 device, but ok - Then i could
have had a issue where
the drive that keeps the metadata is gone... I suspected that I did do
DUP on multiple devices
from the man page:
Note 1: DUP may exist on more than 1 device if it starts on a
single device and another one is added. Since version 4.5.1,
mkfs.btrfs will let you create DUP on multiple devices.
> The check error above means that it wasn't able to map a logical address
> to a physical address. Typically that means that the mapping was lost.
I was more reporting that it happened and if there was any useful data
that we could
extract from this if it's a failure that shouldn't happen :)
I haven't wiped anything yet - preparing to replace the disks though
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