On 5/18/23 12:21, Bill Ricker wrote:
Indeed.P.S. At least /dev/urandom, at least on my current machine, is a lot faster than it used to be. Faster random may be less random ?
I do not think the quality of Linux's /dev/urandom has gone down; it got a major rewrite that I think was motivated to make the code better and cleaner, and the fact that it is also faster was a secondary bit. (Pretty sure /dev/random and /dev/urandom are now exactly the same.)
Whether crypto-secure random is required for cloaking the data later written on the disk depends upon from whom you're hiding!
It could *maybe* be useful from some traffic analysis type snooping. Which is why I quit doing it on new disks.
And it's still better than having 0000 or DEADBEEF blocks as unused space.)
I am a big fan of using decent random data for things like this because I don't trust storage systems to not be clever on me. Maybe I say to write a bunch of 0s and maybe it makes a note "a bunch of zeros here" and very quickly says yes. When I ask for that data it checks its notes and very quickly says 0s. Maybe it says "let me compress this data" in a more general-purpose way, which means I don't even want to write the same quality random data repeatedly.
As I think I have mentioned before, after I unmount one of these disks, if I leave it plugged in I can feel disk activity going on, for quite a while. I assume it is checking and remapping and who knows what. It might be doing maintaining access statistics and doing some caching something something tricks. It might be compressing. Using non-terrible random data is a way to make sure keep some of this from tricking me.
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