Ulrich.Windl at rz
Aug 9, 2011, 11:29 PM
Post #1 of 1
>>> "Fabio M. Di Nitto" <fdinitto [at] redhat> schrieb am 09.08.2011 um 19:36 in
Antw: Re: FYI: Added two new RAs to ocf:xola: bfa-npiv, multipath
Nachricht <4E417008.7010801 [at] redhat>:
> On 8/9/2011 4:58 PM, Ulrich Windl wrote:
> > Hi!
> > Just in case anybody is interested to review or test (please refer to
> "resource-agents-xola-0.2-0.4"): I wrote two more OCF RAs:
> > bfa-npiv that manages NPort ID Virtualization for the Brocade bfa driver
> > multipath that can add, chack and remove multipath maps
> I am not entirely sure I understand the use case for multipath RA.
> multipathd does that already and it can run on multiple nodes at the
> same time.
The thing (according to my experience) is that if you activate the disks exclusively to one node, multipath will never stop complaining if a disk that was found before vanished. The only clean solution (accoring to my experience) is to remove the multipath map before the disk does away. That's where the RA comes in.
> multipathd also monitors changes to devices and bind them to the correct
> entry /etc/multipath.conf etc. etc. etc.
Yes, multipathd adds maps as soon as disks appear, but it doesn't remove maps when disks disappear.
> On top of that, it also executes kpartx to scan for partitions on the
> devices and all done via udev/kernel sockets. So as soon as the kernerl
> discovers the device, it is managed by mpathd.
Yes, but to my experience cleanup when disks vanish isn't as nice. So you need multipath if you also use bfa-npiv IMHO.
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