LVM and VxVM

How to set strict allocation policy

 
Ihab Zaki
Advisor

How to set strict allocation policy

Hello all,

How can I create an lv with PVG-strict allocation policy?

Regards,
Bob
6 REPLIES 6
Michael Schulte zur Sur
Honored Contributor

Re: How to set strict allocation policy

Hi Bob,

have a look here, whether it is enough information.

greetings,

Michael
Michael Schulte zur Sur
Honored Contributor
Patrick Wallek
Honored Contributor

Re: How to set strict allocation policy

YOu need to have a look at the lvcreate man page. The option to lvcreate that you want is '-s g'.
Zeev Schultz
Honored Contributor

Re: How to set strict allocation policy

Hi

The question what do you need it for. The ones in vg00 (system) that use strict allocation are / (lvol3 typically) , /stand (lvol1) and swaps. It surely limits if you decide to extend the logical volume later someday.

Zeev
So computers don't think yet. At least not chess computers. - Seymour Cray
Mark Grant
Honored Contributor

Re: How to set strict allocation policy

Zeev,

Are you perhaps confusing strict/contiguous with PVG-strict today?
Never preceed any demonstration with anything more predictive than "watch this"
Alan Turner
Regular Advisor

Re: How to set strict allocation policy

If the logical volme already exists, you can change it to use strict allocation using the vgchange command. This lets you set up strict allocation on volumes created during system installation. FYI, here's a script I use when setting up mirroring on our system. The bit about rebooting to LV maintenance mode is to do with defining the mirror modes, because the default mirror mode (Mirror Write Cache) is best for sequentially written volumes, but not for randomly-written volumes, and swap/dump should not have any recovery method at all, so I issue the following commands in LV maintenance mode then reboot:

vgchange -a y vg00
lvchange -M n -c n /deb/vg00/lvol2
lvchange -M n -c y /dev/vg00/lvol4
lvchange -M n -c y /dev/vg00/lvol5
lvchange -M n -c y /dev/vg00/lvol6
lvchange -M n -c y /dev/vg00/lvol8