thanks, I understand that meta data blocks needs to be update, that I can understand. how about the other questions? like : data write will happen towards which device? cow device or after the copying has been completed to the origin disk? Skickat från min iPhone > 4 nov. 2019 kl. 16:04 skrev Zdenek Kabelac <zkabelac@xxxxxxxxxx>: > > Dne 04. 11. 19 v 15:40 Tomas Dalebjörk napsal(a): >> Thanks for feedback. >> > >> Scenario 2: A write comes want to write block LP 100, but lvconvert has not yet copied that LP block (yes, I do understand that origin is hidden now) >> Will lvconvery prioritize to copy data from /dev/vg00/lv00-snap to /dev/vg00/lv00 for that block, and let the requestor write the changes directly on the origin after the copying has been performed? >> Or will the write be blocked until lvconvert has finished the copying of the requested block, and than a write can be accepted to the origin? >> Or where will the changes be written? > > Since the COW device contains not only 'data' but also 'metadata' blocks > and during the 'merge' it's being updated so it 'knows' which data has > been already merged back to origin (in other words during the merge the usage of COW is being reduced towards 0) - I assume your 'plan' stops right here > and there is not much point to explore how much sub-optimal the rest of merging process is (and as said - primary aspect was robustness - so if there is crash in any moment in time - data remain correct) > > Regards > > Zdenek > _______________________________________________ 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/
