[LinuxFailSafe] drbd resource script patch

[Lars Marowsky-Bree]

On 2002-05-08T16:55:52,
   Martin Bene <martin.bene@icomedias.com> said:

Hi Martin,

thanks for the patch! I have folded it into CVS; as I couldn't test drbd
locally, I will trust your code.

I have thought about how to handle drbd resources cleanly with FailSafe; the
scheme is actually pretty similiar for any active/replicated resource, like
databases etc. If you are using drbd, you might find this helpful - I haven't
tried it, but I think it makes sense; input and patches appreciated ;-)

- FailSafe should not only control the primary, but also the secondary via a
  resource.

  (ie, the secondary is "online pending" until it is fully sync'ed etc)
  
- The primary resource _knows_ about this and can control the secondary
  resource.

- A special failover policy script will automatically pick the right node for
  the primary.
  
> drbd is a nasty resource to handle while resync is in progress: it can not
> be stopped, and for successfull startup, it MUST be started on the node
> where it's already primary. The patch tries to accomodate this by moving
> some of the startup checks from exclusive to start: for exclusive check, the
> node where the resource will be started is still unknown, so it's not
> possible to handle drbds requirements. Correct check can only be made at
> start time. Fortunately, failsafe is persistent enough to get the drbd
> resource correctly online for all reasonable device states. 

The failover script could take this into account.

A very minor nit pick - could you try to set your line-length in e-mail to 78
characters or so?


Sincerely,
    Lars Marowsky-Brée <lmb@suse.de>

-- 
Immortality is an adequate definition of high availability for me.
	--- Gregory F. Pfister