[smartmontools-support] TBW for SATA disks

[Dan MacDonald]

I have a couple of Samsung SATA3 SSDs in a server that I discovered
weren't working at full performance any more by running `hdparm -t` on
them. Running both short and long smartctl tests on them said they
were OK tho.

I had a bit of a search online and I found these scripts which use
smartctl to calculate a TBW percentage for each disk:

https://askubuntu.com/questions/865792/how-can-i-monitor-the-tbw-on-my-samsung-ssd

It would seem that if you get a TBW under 90% your disk probably needs
to be replaced, at least thats turned out to be the case with my
Samsung SSDs in a RAIDZ2 pool. Instead of having to use one of these
scripts or commands it would be better to have this feature integrated
into smartctl.

Is TBW calculation/output already present but I've not found the right
option or is there a better way to check the health of SATA SSDs than
using one of these TBW scripts?