dd

Direct sync write benchmark Worst-case durable write speed (no cache, sync each block); note: not an IOPS test dd if=/dev/zero of=/data/ddtest bs=1M count=1024 oflag=direct,dsync status=progress; rm /data/ddtest #dd#disk#performance#troubleshooting Clone disk with progress Block-clone whole disk; conv=noerror,sync keeps copying past bad sectors as zeros dd if=/dev/sda of=/dev/sdb bs=64M conv=noerror,sync status=progress #dd#disk#troubleshooting#performance