/etc/lvmrc questions

[Brent Hardesty]

Trying to understand lvmrc better. We have AUTO_VG_ACTIVATE = 0 as we have MCSG on this system. We have other vg's that we wanted activated at boot time. Why in the custom_vg_activation vgchange use the flag -s (disabling vgsync) and then go and call parallel_vg_sync where it then syncs the vg with its mirror? Why doesnt it just vgchange -a y and let the activation automatically sync the vg withits mirror? Our lvmrc file currently looks like this:
/sbin/vgchange -a y /dev/vg00
parallel_vg_sync "dev/vg00" which to me seems like it would be syncing the vg twice. Am I correct? Everything is working fine, but I just want to try to understand this better. Couldnt I just have /sbin/vgchange -a y /dev/vg00 under the custom_vg_activation routine and have vg00 both activated and synched and not call the parallel_vg_sync routine?

Thanks,
Brent

[Lou Zirko_1]

If you are only doing vg00 then there is not a need to call the parallel_vg_sync function. It's there only to help with syncing multiple vg's in "parallel".

Lou Zirko

[Brent Hardesty]

Lou: So the 'parallel' is there just for performance (speed) of synching (two at a time vs. one at a time with the vgchange)? What if I did have, lets say 10 other vg's? I could just use the vgchange -a y vgname and ignore the parallel sync correct? Understanding that it would take longer to complete the synching process.

Thx,
brent

[Christopher McCray_1]

Another thing, you don't need vg00 in lvmrc because it is the only one that is automatically activated at boot time, unless you specify in parallel.

Chris

[Lou Zirko_1]

To answer your last question, you do not need to use the parallel option at all.

Lou Zirko

[Roger Baptiste]

Brent,

I have cluster systems which
do not use the paralle_vg_sync
option at all.

-raj