On lvm2 2.02.183, man lvcreate includes: -Z|--zero y|n Controls zeroing of the first 4KiB of data in the new LV. Default is y. Snapshot COW volumes are always zeroed. LV is not zeroed if the read only flag is set. Warning: trying to mount an unzeroed LV can cause the system to hang. This says only the "first 4KiB" is zeroed. Yet, when running "lvcreate --chunksize <something large>", it says: WARNING: Pool zeroing and ###.00 MiB large chunk size slows down thin provisioning. WARNING: Consider disabling zeroing (-Zn) or using smaller chunk size (<512.00 KiB). Which seems to indicate it's going to zero the entire newly allocated chunk size, rather than only the first 4KiB. The lvcreate warning goes more along with the purpose of zeroing, to prevent reading data one shouldn't have access to. _______________________________________________ linux-lvm mailing list linux-lvm@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
