On 2/3/2015 2:44 PM, Joe Julian wrote:
On 02/03/2015 11:34 AM, Ted Miller
wrote:
On 2/3/2015 12:23 PM, Joe Julian wrote:
****************************************************************
That brought another thought to mind (have not had reason to
try it):
How does gluster cope if you go behind its back and rename a
"rejected" file? For instance, in my example above, what if
I go directly on the brick and rename the host-2 copy of the
file to hair-pulling.txt-dud? The ideal scenario would seem
to be that if user does a heal it would treat the copy as
new file, see no dupe for hair-pulling.txt, and create a new
dupe on host-2. Since hair-pulling.txt-dud is also a new
file, a dupe would be created on host-1. User could then
access files, verify correctness, and then delete
hair-pulling.txt-dud.
This should cause you to have two files with the same gfid.
This will create the hardlink in .glusterfs again, and the
heal will then re-create the .txt file also with that same
gfid. Since both files will have the same gfid (stored in
extended attributes) and be hard linked to the same file under
.glusterfs you should then end up with both files being
split-brain.
Joe, I moved you comments up to be closest to the proposal they
seem relevant to.
*****************************************************************
A not-officially-sanctioned way that I dealt with a
split-brain a few versions back:
1. decided I wanted to keep file on host-2
2. log onto host-2
3. cp /brick/data1/hair-pulling.txt
/gluster/data1/hair-pulling.txt-dud
4. rm /brick/data1/hair-pulling.txt
5. follow some Joe Julian blog stuff to delete the
"invisible fork" of file
6. gluster volume heal data1 all
If you note, in the above scenario I copied from the brick
to the mounted gluster volume. I believe that this forces
the breaking of any linkage between the old file and the new
one. Am I missing something there?
Yep, I missed that. I seem to be suffering from split-brain,
myself, today.
Don't sweat it, your blog posts have dug me out of more than one
hole.
Ted Miller
Elkhart, IN, USA
.
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