[DRBD-user] Drbd 0.7.12 - Buffer I/O error on device drbd0

Lars Ellenberg Lars.Ellenberg at linbit.com
Fri Aug 26 17:53:43 CEST 2005

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

/ 2005-08-26 11:39:26 -0400
\ Poyner, Brandon:
> > well, if someone tries to write to the secondary,
> > he gets an io error, and the message is "no io allowed".
> > if someone tries to read from the secondary, 
> > he gets an io error, and the message is "no io allowed".
> > where is the problem?
> The problem is the assumption that I know what was going on.  It's one
> thing if I were trying to mount the device, I could directly see the
> relation between my commands and the error.  It's another matter when
> that error shows up over night for no obvious reason.  Normally I'd be
> left wondering 1) what tried to access the device 2) was the IO request
> read or write 3) and is this a serious error?  I don't think the drbd
> module would have direct access to #1 (yes/no?).  It should know the
> answer to #2, and #3 depends on #1 and #2.  If I only had access to #2 I
> could make a more informed decision.

#1: we could log the current comm and pid, if that helps.
#2: see below.

> > I can make the message read
> > "neither read nor write requests allowed while in secondary mode"
> > 
> > if you are worried about failing writes,
> > watch out for kernel messages like
> > "lost page write due to I/O error on <devicename>"
> > and similar...
> Ok, that's helpful, but I stand by my assertion that clarifying the IO
> type would help me figure out the gravity of the situation.

as a secondary cannot be opened with write intent,
write requests cannot be submitted.

: Lars Ellenberg                                  Tel +43-1-8178292-0  :
: LINBIT Information Technologies GmbH            Fax +43-1-8178292-82 :
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