blocksize when using dd to copy disks? bigger = better?

Joachim Rosenfeld joerosenfeld at
Tue Sep 23 15:32:43 UTC 2008

When mirroring a disk with dd, I notice that a blocksize of 512 runs
awfully slow, but with bs=1MB (2^10bytes), it runs fairly quickly.

Can someone explain the implications of this? Did all the data not
copy properly with the larger blocksize?


More information about the freebsd-questions mailing list