On 17/03/2017 12:11, Peter Lieven wrote: >>> like VMDK or QCOW2 shouldn't we trust the information from the l2 tables in >>> the VMDK or QCOW2? >> It provides additional information, for example it works better with >> prealloc=metadata. > Okay, understood. Can you imagine of a away to conditionally avoid this > second callout? In my case we have an additional > lseek for each cluster. For a 20GB file this are approx. 327k calls to lseek. > And if the file has no preallocated metadata > it will likely not improve anything. And even if the metadata is prealloced > what is the allocation status of the clusters?
If the metadata is preallocated, cluster will (or should) show up as zero, speeding up the copy. Paolo
