On 2018-12-06 23:09, Andrei Borzenkov wrote:
06.12.2018 16:04, Austin S. Hemmelgarn пишет:
* On SCSI devices, a discard operation translates to a SCSI UNMAP
command. As pointed out by Ronnie Sahlberg in his reply, this command
is purely advisory, may not result in any actual state change on
06.12.2018 16:04, Austin S. Hemmelgarn пишет:
>
> * On SCSI devices, a discard operation translates to a SCSI UNMAP
> command. As pointed out by Ronnie Sahlberg in his reply, this command
> is purely advisory, may not result in any actual state change on the
> target device, and is not
On 2018-12-06 01:11, Robert White wrote:
(1) Automatic and selective wiping of unused and previously used disk
blocks is a good security measure, particularly when there is an
encryption layer beneath the file system.
(2) USB attached devices _never_ support TRIM and they are the most
likely
Hi,
I am more of a SCSI guy than ATA so forgive where I am ignorant.
The SCSI equivalent to TRIM is called UNMAP.
UNMAP is unfortunately only a "hint" to the device so if the device
for any reason
is busy, it can just do a NO-OP, leave the data as is and still
return status SUCCESS.
That is
On Thu, 6 Dec 2018 06:11:46 +
Robert White wrote:
> So it would be dog-slow, but it would be neat if BTRFS had a mount
> option to convert any TRIM command from above into the write of a zero,
> 0xFF, or trash block to the device below if that device doesn't support
> TRIM. Real TRIM
(1) Automatic and selective wiping of unused and previously used disk
blocks is a good security measure, particularly when there is an
encryption layer beneath the file system.
(2) USB attached devices _never_ support TRIM and they are the most
likely to fall into strangers hands.
(3) I
