checking old ssd health and formatting on linux

u know that old ssd sitting around? wanna know if its healthy before using it?

today were gonna do the full check-up and then the full reset on it using the fedora terminal!

checking health with smartmontools

first, lets see if the ssd is healthy or dying...

we use a program called smartmontools:

sudo dnf install smartmontools

now u need to know the "name" of ur disk. run lsblk to see. mine was /dev/sda.

with the name, run the health test:

sudo smartctl -a /dev/sda

what to look for in the result? the most important line is this one:

SMART overall-health self-assessment test result: PASSED

its also good to check Reallocated_Sector_Ct (ID 5). if the RAW_VALUE is 0 (zero), its perfect!

cleaning the ssd with blkdiscard

ok, my ssd was PASSED. but it was an extra disk (my fedora was on another one) and i wanted to erase everything and leave it clean.

sudo blkdiscard /dev/sda

if it works, it says something like:

/dev/sda: Discarded 512110190592 bytes from the offset 0

all clean.

"but did it really erase? can it be recovered?"

and the answer is: no, it cant be recovered.

blkdiscard uses trim. its different from formatting an old hdd.

• it doesnt write zeros over the data, like secure formatting an hdd does.
• it talks directly to the controller (the ssd boss): "hey, u can throw away the 'map' that leads to this data. i dont need it anymore."

the physical data (the electrons) might stay in the chip for a bit, but the controller wont let anyone read it! if any program tries to read, the controller just returns zero.

so for us, the data disappeared 100% the second blkdiscard ran.

formatting

now the ssd is clean, but it has no "drawers" (partitions) to store stuff.

creating the partition (fdisk)

to create the partition, we use fdisk:

sudo fdisk /dev/sda

inside fdisk, u just need to press keys and hit enter (in order):

• g (to make a new gpt table)
• n (for a new partition)
• enter (to accept the partition number)
• enter (to accept the first sector)
• enter (to accept the last sector, using the whole disk)
• w (to save and exit)

formatting the partition (mkfs.ext4)

lets use ext4 which is perfect for linux, its the standard and super stable.

sudo mkfs.ext4 /dev/sda1

done!

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