On 7/1/21 7:55 PM, David Wright wrote:
On Mon 28 Jun 2021 at 13:36:35 (-0700), David Christensen wrote:
I do not set the 'discard' (trim) option in fstab(5). If and when I
want to erase unused blocks (such as before taking an image), I use
fstrim(8).
Can you elaborate on a couple of things:
How do you "take an image". Is this equivalent to a conventional
dd if=/dev/sda …, or to some other process?
I wrote a script. To "take an image", the script invokes dd(1) and
pipes the output to gzip(1), copying raw device octets to a file. To
"restore an image", the process is reversed.
When I copy an entire conventional drive or partition, all the
free blocks/unused sectors are carefully transferred to the copy.
Same here.
What improvement does erasing unused blocks achieve?
Zero blocks are readily compressed, reducing the size of the image file.
David
