Am 25.10.23 um 17:42 schrieb Simon Becherer:
Am 25.10.23 um 16:42 schrieb Aaron Digulla:
Am 25.10.23 um 15:36 schrieb Simon Heimbach:
Hi everybody,
does anyone know how to securely format a btrfs-partition[1]? I have an unused SSD with a former root partition that I have to return and I want to make sure that all data is erased before giving it back.
The SSD controller will map arbitrary regions to arbitrary blocks of the disk, so just overwriting every block isn't working as you'd expect - usually, the controller will send writes to new, unused blocks and leave the old data alone to spread wear evenly.
Only for my understanding: (i have no deeper idear how ssd's work) i know that ssd's have !some! size more to map bad parts. but: did a ssd have several times the size that is printed on the cover (and shown if i use partimage/gparted?)
this would be the only reason why overwriting all with random data would not work. - or if the ssd is intelligent and see that this is random data, and if i read it it will generate !!the same!! random data. if writing direct with cut or dd to the blocks, also writing to a huge file is (with my at the moment knowledge) a option top overwrite all.
i am interested because i do not understand your explanation why this did not work (ok, maybe some small parts of the reserve parts of the ssd will with this not be overwritten) but doing the overwriting step more than one time should also in theory delete this by "spread wear evenly"
simoN
well i do still not understand it. have read a lot inside the net, here is another nice explanation (in german): https://wiki.ubuntuusers.de/SSD/Secure-Erase/ simoN
-- www.becherer.de