[Linux-ha-dev] New master/slave resource agent for DB2 databases in HADR (High Availability Disaster Recovery) mode
dejanmm at fastmail.fm
Wed Feb 9 09:05:08 MST 2011
On Wed, Feb 09, 2011 at 02:19:02PM +0100, Lars Marowsky-Bree wrote:
> On 2011-02-09T11:56:53, Dejan Muhamedagic <dejanmm at fastmail.fm> wrote:
> > Great! Unfortunately, we can't replace the old db2 now, the
> > number of changes is very large:
> That, by itself, doesn't strike me as a reasonable argument for
> duplicating the RA.
Look, if I could tell that changes were safe, then I certainly
wouldn't moan about it. If you can, please go ahead.
> It may seem a reasonable idea to protect existing
> setups, but consider that it leads to user confusion (which should they
> use?), requirements to change setups if they drift apart, and not to
> mention code duplication, which is a maintenance nightmare.
> We've done it once (with IPaddr2 and IPaddr), and personally, that has
> convinced me that it is a bad idea ;-)
And it definitely is a bad idea. But this case is different from
IPaddr*. IPaddr* are two RAs covering the same functionality
but using different tools. db2* use the same tools.
> So, working from the assumption that the new 'db2' RA is supposed to be
> backwards-compatible with the existing one, except that it adds new
> A reasonable approach - in my opinion - would be to add a few test cases
> (starting with ocf-tester, and perhaps testing one or two failure
> scenarios), that work with the old code, and which would help prove the
> new RA is compatible and doesn't introduce regressions. Of course, tests
> that also exercise the new functionality are welcome.
> If they pass, we can be sure that the new RA is, indeed, a drop-in
> replacement like it should be, and we can avoid shipping both.
> I know it's somewhat heavy to put the burden of tests on to the new
> contributor (it'd be better if we already had some to verify what we
> already ship), but we desperately need test coverage for our RAs, since
> they provide crucial and essential integration code.
> To make up for that, I'll personally invite everyone who contributes a
> reasonably comprehensive, non-trivial test suite for an RA to lunch.
> (Just sayin', so that not everyone tries to get a free lunch out of
> testing the Dummy RA ;-)
OK. You've been a PM for a while, perhaps you could estimate the
effort needed to setup and run a regression test for db2? Or SAP?
> Architect Storage/HA, OPS Engineering, Novell, Inc.
> SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg)
> "Experience is the name everyone gives to their mistakes." -- Oscar Wilde
> Linux-HA-Dev: Linux-HA-Dev at lists.linux-ha.org
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