[Gluster-devel] 1.4 AFR vs Roadmap Page

Martin Fick mogulguy at yahoo.com
Fri Dec 5 01:10:35 UTC 2008


Hi guys,

I would like to ask a question about the current 1.4 AFR implementation.  On the roadmap page:
  http://www.gluster.org/docs/index.php/GlusterFS_Roadmap

it says:

  #  AFR atomic writes - handle total power-loss, split-brains,.. (bullet-proof AFR)


While I know that there have been some improvements to AFR mentioned on this list, mainly file locking on append (or something like that), I really did not get the impression that any of the improvements were close to making AFR "bullet-proof" or anti-split brain.  Are there many changes in this regards that have not been explained here?  My impression was that the 1.4 AFR still couldn't handle the following simple split brain scenario yet:

Server A & B AFRed

1) Server B goes down
2) Server A has file FOO deleted on it
3) Server A goes down
4) Server B comes up

Will split brain be detected, or will server B gladly serve up file FOO still?  Please, don't take my question as a criticism, I really am just trying to figure out whether the roadmap page is hyping up the capabilities of 1.4 AFR or not, and if so if perhaps the wording should be softened? :)

Thanks,

-Martin



      





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