Wednesday, December 21, 2011

lvm stuff

note to self

Encountered "Found duplicate PV" warning again, i keep forgetting the solution for some reason. Good KB article is here.

Idea is to filter out everything that has multiple device files leaving only one, and making sure the one that is left is the best one to be used. For example, in a multipath environment filter out everything except the multipath'd device node created by the device-mapper or whichever multipath tool that is used. ( Eg. /dev/emcpowera etc. )

Once the changes are in place pvscan and vgscan can be issued and check the warning appears no longer.

Example filter rule from the current SLES san-boot setup this was tested is below. It filters out everything except /dev/dm-* devices which are the multipath devices created by device mapper.
filter = [ "a|/dev/dm-.*|", "r|.*|" ]
Once this is tested, mkinitrd should be done to put the changes in to the initrd image to be activated at the boot.

uefi boot stuff

note to self

Came across this strange problem with SLES 11 SP1.

When installing on a UEFI enabled hardware, the system doesn't allow to create a LVM based partitioning scheme.

According to tech-support it is due to be a bug in SP1, only to be fixed in SP2 which is due first quarter next year.

Workaround is to create a separate /boot/efi , /boot in traditional partitions and rest inside the LVM as usual. Found this out from the good folk at #lvm. Looks more like a limitation of UEFI boot, rather than a OS bug to me.