On Fri, Feb 01, 2019 at 05:03:40PM +0100, Heinz Mauelshagen wrote: > On 2/1/19 3:09 PM, John Dorminy wrote: > > I didn't know such a thing existed... does it work on any block > > device? Where do I read more about this? > > > Use sg_write_same(8) from package sg3_utils. > > For instance 'sg_write_same --in=foobarfile --lba=0 --num=20000 > --xferlen=512 /dev/sdwhatever' > > will read the pattern to write same from file 'foobarfile' with length > explicitely set to 512 bytes > (rather than derived from foobarfile's size) and write it 20000 times > starting at LBA 0 to /dev/sdwhatever. Yeah. Note that this will only work on SCSI disks (and maybe ATA for a very specific corner case). But for actual devices and not remappers the same is true of REQ_OP_WRITE_SAME. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
