Use a mirrored mirror log
Use a mirrored mirror log

By default, LVM will sync the two mirrors of a logical volume on
creation. This is I/O intensive and it takes a long time though, so we
tell it not to with --nosync. The next default behavior is to create a
mirror log which says what portions of the mirrors are in sync. But
then if a disk backing a mirror log fails, we have to deal with
resyncing the mirrors at each reboot.

This commit tells LVM to use a mirrored mirror log, which will use
approximately 4MB of extra space, but means we'll never have to
sync mirrors, ever.

Change-Id: I6586ced4e7e66ae79ae134406a4c633f8fbc8602

Accelerite/cinder,alex8866/cinder,redhat-openstack/cinder,rakeshmi/cinder,scottdangelo/RemoveVolumeMangerLocks,nikesh-mahalka/cinder,scality/cinder,scottdangelo/RemoveVolumeMangerLocks,Datera/cinder,phenoxim/cinder,hguemar/cinder,takeshineshiro/cinder,Paul-Ezell/cinder-1,nexusriot/cinder,phenoxim/cinder,github-borat/cinder,Thingee/cinder,Akrog/cinder,tlakshman26/cinder-bug-fix-volume-conversion-full,potsmaster/cinder,redhat-openstack/cinder,eharney/cinder,nikesh-mahalka/cinder,Thingee/cinder,saeki-masaki/cinder,rakeshmi/cinder,JioCloud/cinder,Nexenta/cinder,Accelerite/cinder,mahak/cinder,manojhirway/ExistingImagesOnNFS,bswartz/cinder,j-griffith/cinder,ge0rgi/cinder,abusse/cinder,cloudbase/cinder,spring-week-topos/cinder-week,Paul-Ezell/cinder-1,winndows/cinder,petrutlucian94/cinder,dims/cinder,julianwang/cinder,leilihh/cinder,NetApp/cinder,openstack/cinder,Akrog/cinder,spring-week-topos/cinder-week,NeCTAR-RC/cinder,tlakshman26/cinder-https-changes,j-griffith/cinder,hguemar/cinder,mahak/cinder,sasukeh/cinder,cloudbase/cinder,CloudServer/cinder,bswartz/cinder,scality/cinder,Nexenta/cinder,Thingee/cinder,eharney/cinder,leilihh/cinder,tlakshman26/cinder-bug-fix-volume-conversion-full,Datera/cinder,tlakshman26/cinder-new-branch,blueboxgroup/cinder,tlakshman26/cinder-new-branch,petrutlucian94/cinder,apporc/cinder,NetApp/cinder,manojhirway/ExistingImagesOnNFS,tlakshman26/cinder-https-changes,openstack/cinder,duhzecca/cinder,duhzecca/cinder,apporc/cinder,sasukeh/cinder,Hybrid-Cloud/cinder,NeCTAR-RC/cinder,Hybrid-Cloud/cinder,blueboxgroup/cinder,alex8866/cinder,julianwang/cinder,saeki-masaki/cinder,nexusriot/cinder,JioCloud/cinder,takeshineshiro/cinder,winndows/cinder,potsmaster/cinder,CloudServer/cinder,dims/cinder,github-borat/cinder,abusse/cinder