[Gluster-devel] Files erased while one brick was down in AFR returns from the afterlife

[Daniel van Ham Colchete]

People,

Gerry Reno raised a very interesting question about AFR.

Let's imagine the following case: two bricks AFRed. I create a few files
(say mail files inside a Maildir). The second brick goes down. I erase a few
e-mails (checking my POP3 account). Them I bring back the second brick. The
files created/changed during this time will be copied to the second as soon
as I open() them. The problem is: if I "ls -la" I'll see the old erased
files. If I try to open them GlusterFS will even replicate it. Why this is
happening: when I do a "ls -la" Gluster will check both bricks and give the
list of files inside both servers.

I'm using only AFR, without unify. I tested it here and got the expected
result.

I can propose one solution for this problem. If you apply the same
versioning algorithm used with files to the directories themselves the
self-heal could detect witch dir has the newest file list and erase what's
necessary.

What do you think?

Best regards,
Daniel Colchete