[DRBD-user] Clarification on How-To

Alan Robertson alanr at unix.sh
Fri Sep 17 04:30:45 CEST 2004

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

Nuno Tavares wrote:
> Alan and John,
> This is *NOT* true, at least for 0.6.x, I still hadn't the time to 
> switch to 0.7.x though.

Exactly *what* is not true?  DRBD will never use out-of-date data unless a
human tells them otherwise?  If it does, then that's a major bug, which
would require immediate attention.  That's pretty much all I said.

> DRBD (used to have?) has a legacy mode, which will always keep DRBD as 
> secondary onboot, so that a cluster manager (as Heartbeat) can 
> coordinate the transitions. I ask Lars to confirm this behaviour on 0.7.x.

It doesn't matter which side is brought up as writable, and which as
non-writable.  That's not terribly important, since it's easily changed.
What's really important is which copy of the data is treated as good.  In
the older versions, this was tied tightly to which side was "master".  In
recent versions, that's not true any more.

Perhaps you missed that the discussion was about getting started the first
time.  This is a bit of a special case, since neither side has known good
data yet.

> If confirmed, I recomend you read section 4.1.2 of this HOWTO[1], where 
> this configuration has been working for several weeks.

Perhaps you read the article I published on DRBD and heartbeat in Linux
Magazine in November 2003[1]?  Or the one that l.g.e. wrote in the same
issue of the same magazine at my request[2]?  Or maybe read the archives
from a few years ago where I started the discussions about the "old data"
issues, data integrity, and so on with Phillip?   I'm sure you're aware
that what he implemented was based on my recommendation.[3]

Thanks to the pointer to your article. I added a pointer to your web site
to the old and new versions of the Linux-HA web site[4,5].

[1]	http://www.linux-mag.com/2003-11/availability_01.html
[2]	http://www.linux-mag.com/2003-11/drbd_01.html
[3]	http://www.drbd.org/fileadmin/drbd/publications/drbd_lk9.pdf
[4]	http://linux-ha.org/
[5]	http://linux-ha.trick.ca/PressRoom

     Alan Robertson <alanr at unix.sh>

"Openness is the foundation and preservative of friendship...  Let me claim
from you at all times your undisguised opinions." - William Wilberforce

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