[DRBD-user] "Concurrent local write detected!"

Chris Worley worleys at gmail.com
Thu Dec 30 00:13:56 CET 2010


On Wed, Dec 29, 2010 at 3:28 PM, Dan Barker <dbarker at visioncomm.net> wrote:
>> From: drbd-user-bounces at lists.linbit.
>> Sent: Wednesday, December 29, 2010 4:49 PM
>>
>> I really think drbd is being brain-dead here.  Concurrent writes to
>> the same LBA aren't an issue... just do it!  Note the below is using a
>> primary/secondary setup on two raw drbd devices; no GFS anywhere.
>
> <snip>
>
> But the result is undefined! What should DRBD write to the other member? The
> result of the first or the second write?
>
> You are using a tool that permits the execution of stupid I/O streams. Good
> for stress testing, but not good for data integrity. If you want undefined
> data on a DRBD pair, then disconnect before the I/O, do the undefined thing,
> and upon reconnect DRBD will faithfully replicate the garbage. It will still
> be  undefined stuff, but it will be identical undefined stuff.
>
Are you seriously thinking that Unix doesn't allow two writes to the
same LBA simultaneously?

This is part of Unix file system semantics.

A dead system is not the proper outcome.

Chris



More information about the drbd-user mailing list