[ClusterLabs] Antw: Re: Question on sharing data with DRDB

[Ulrich Windl]

>>> Valentin Vidic <Valentin.Vidic at CARNet.hr> schrieb am 20.03.2019 um 19:00
in
Nachricht <20190320180007.GX9348 at gavran.carpriv.carnet.hr>:
> On Wed, Mar 20, 2019 at 01:47:56PM ‑0400, Digimer wrote:
>> Not when DRBD is configured correctly. You sent 'fencing
>> resource‑and‑stonith;' and set the appropriate fence handler. This tells
>> DRBD to not proceed with a write while a node is in an unknown state
>> (which happens when the node stops responding and is cleared on
>> successful fence).
> 
> The situation I had in mind is this: node1 is Primary and sends a write to
> local disk and over the DRBD link. The network fails so the write is
> successfull only on the local disk. node1 is than fenced and node2 takes
> over but the disk have now diverged.

Actually it makes no difference to a non-clustered local disk: If the buffers
are not flushed, data can get lost if there is a power failure. If you use sync
writes, the data should be on disk, and I guess with DRBD the data should be on
the remote site also.

> 
> ‑‑ 
> Valentin
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