Tejas Sumant wrote: > 3) Why the metadata inside MDA wraps around, instead of the offset > pointing to the start of metadata? Metadata updates run in two steps: - write() saves the new metadata to new place (circular buffer) but still keeping previous version active. (Also operation can be safely reverted here, because there are still old version of metadata prepared.) - commit() switch the pointer to new offset and activate new metadata. This operation is atomic (one synchronous sector write) so it cannot corrupt active metadata copy. (If the write fails, old metadata are still valid.) (Imagine for example power failure during metadata write operation.) There is serial number in metadata, lvm will update mda content to newest metadata if any copies are older. Milan -- mbroz@redhat.com _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
