[DRBD-user] /proc/drbd, 5th flag, "d"

Lars Ellenberg lars.ellenberg at linbit.com
Tue Feb 5 09:53:57 CET 2013

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


On Mon, Feb 04, 2013 at 05:44:48PM -0500, Marcelo Pereira wrote:
> Hello Everyone,
> 
> I just noticed a flag on one of the DRBD resources, as shown below:
> 
> > [ /]# cat /proc/drbd
> > version: 8.3.13 (api:88/proto:86-96)
> > GIT-hash: 83ca112086600faacab2f157bc5a9324f7bd7f77 build by dag at Build64R6,
> > 2012-05-07 11:52:13
> >  0: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate C r-----
> >     ns:2081916088 nr:520248 dw:2082436336 dr:1001913178 al:1585314 bm:132 lo:0
> > pe:0 ua:0 ap:0 ep:1 wo:b oos:0
> >  1: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate C r---d-
> >     ns:1035652 nr:0 dw:1035652 dr:7682 al:270 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1
> > wo:b oos:0
> 
> The DRBD manual says about the "d" on the 5th flag:
> 
> > Locally blocked I/O. Normally. May be one of the following flags:
> > 
> >     d: I/O blocked for a reason internal to DRBD, such as a transient disk
> > state.

Is IO in fact blocked?
Or are you just worrying about that flag in /proc/drbd ?

We cache the result of our drbd_congested() hook whenever it is called
by the VM subsystem or generic writeout path, or the like.
We used to not reset that information actively.
So it reset only when "someone" called into that hook again later.

This means that flag may display stale information /proc/drbd.
Fixed in 8.3.14 and above.

	Lars

> I have checked the logs (/var/log/messages), and there is nothing there from
> DRBD.
> 
> There server is running on:
> * CentOS 6.3
> * Kernel 2.6.32-220
> Any suggestion on how to find out what is causing that flag to be up?
> 
> Thanks,


-- 
: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.
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