Hi Hertha/Gerrard/anyone, SAN disk partitions device files changes with each reboot

[Gerrard Geldenhuis]

> -----Original Message-----
> From: redhat-list-bounces at redhat.com [mailto:redhat-list-
> bounces at redhat.com] On Behalf Of Gerrard Geldenhuis
> Sent: 27 May 2008 10:52
> To: General Red Hat Linux discussion list
> Subject: RE: Hi Hertha/Gerrard/anyone,SAN disk partitions device files
> changes with each reboot
> 
> 
> Please, please read the document... its not that long and would be an
> hour well spend. It discusses things like adding exception lists in
lvm
> which prevents lvm scanning inactive backup luns, which could
> subsequently cause them to become active, possibly creating lots of
> uneccesary swapping between paths.
> 
> Regards
> 

I was busy doing some documentation and read through my notes on san
configuration. I thought I might post it here because it slightly
clarifies my previous post. Please bear in mind that this is specific to
us and it is still adviced to read the multipath documentation.

Update the line in /etc/lvm/lvm.conf that starts with [filter] giving it
the following value:
filter = [ "r/disk/", "r/sd.*/", "a/.*/" ]

This line prevents lvm from scanning /dev/sda and other devices for LVM
data. As LVM is already accesing the SAN volumes via the devices created
by multipath we don't want it to also access the devices using /dev/sda
or /dev/sdb. Furthermore doing this will cause the SAN to failover
because it would be detecting a read request on a passive path and then
fail over to the passive path.

Regards