[Gluster-devel] Client side afr, locking, race condition, simultanous writes, out of sync

[Martin Fick]

--- gordan at bobich.net wrote:
> On Fri, 9 May 2008, Anand Babu Periasamy wrote:
> > You are always expected to hold locks and issue
> > writes in a multi user mode.

In the real world people will use scripts without 
locks and will risk corruption.  This corruption 
should only affect the application.  Here we are
talking about backup utilities and other 
applications that will potentially be affected. 
Imagine a file that is inconsistent and untouched 
for years after that, it could return alternating
results every night on a backup making backups
excessive.  It could trigger an rsynced volume to
constantly resync.  These are not issues that a
filesytem should introduce.


> ... but what happens when both sides are 
> appending to the file? Logs being an obvious 
> example - they are not always locked.

For the record, I tested this yesterday and 
if you modify the stress script to append to 
each file; you will see similar inconsistent 
split brain activity.

-Martin



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