On Thursday 29 August 2002 15:35, Joe Thornber wrote: > I think there's some confusion about what vgscan will be doing and > where the filters fit in. Certainly I just had to look at the code to > remind myself: > > vgscan will stat *every* device under the /dev tree (or elsewhere if > you've specified a different dev dir). > > If the device is a block device it will then pass it through the > predicate functions/filters in the following order: > > i. Regex - is the device accepted by the regexs specified in lvm.conf? > > ii. LVM check - is this device a 'recognised' device type. eg, IDE, > md, loop etc. > > iii. Is it a valid partition number. > > iv. Can I successfully open the device > *** This is the expensive operation for non existent devs *** > > Personally I see no need for checks ii. and iii. they will probably > disappear. > > So with your filter which accepts every device containing 'sda' you > will find that /dev/ide0 is 'stat'd but no more than this. However > with /dev/sda8 (non existent) you will get as far as the open test > before being rejected. > > Once vgscan has been run the tools will not even stat failed devices. > > NOTE: You don't always need to run vgscan on startup with LVM2, > only if you know some devices have moved - I just run 'vgchange -ay' in > my init script. > > - Joe Thanks for the explanation, it's clear now what's happening. Wim Bakker _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html
