[DRBD-user] Write barriers with ext3 (-o barrier=1)

Lars Ellenberg lars.ellenberg at linbit.com
Fri Sep 12 21:53:04 CEST 2008

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


On Fri, Sep 12, 2008 at 07:15:48PM +0200, Lars Volker wrote:
> Hallo everybody,
>
> i'm currently trying to get barriers to work on ext3. So far I have been  
> successful, but when it comes to DRBD, barriers don't seem to be  
> supported. Let me describe the setup.


> The question is: Could someone please comment on the current status of  
> write barriers with drbd?

Unsupported.

Problem:
reliably figure out wether local disk _and_ peer disk support them.

we use barriers, if available, for some of our housekeeping IO.
but we currently do not support them for upper layers.

this may change if we figure out a way to do it "right".

for now we rather say "EOPNOTSUPP", than silently accept and pretend we'd
support them, and then find out later that it somehow did not work out.

-- 
: Lars Ellenberg                
: LINBIT HA-Solutions GmbH
: DRBD®/HA support and consulting    http://www.linbit.com

DRBD® and LINBIT® are registered trademarks
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