How-to "under-provision" your SSD?

[voodooFX]

I have a 480GB SSD which I would like to under provision to 32GB but I can not find any reference on how to do this, I'm googling since 1 hour and at this point I think there is something wrong, maybe I'm searching with the wrong terminology?

Anyway, does anyone know how to do that (in freeBSD?)
I thought this would be very common since it's suggested in every single SLOG reference guide, but apparently it's not...

 

[nthu9280]

Disclaimer - i've not done it.

Check the docs/man for sg_format --resize

 

[voodooFX]

wait, is it just a matter of creating a 32GB partition?

 

[voodooFX]

Thanks nthu9280, we answered together

Looks like 'sg_format --resize' is doing what I was thinking is needed, but I also found this: how to partition zil ssd drive to underprovision ?

this guy is simply adding a smaller partition and giving the partition as slog, uhm...

 

[voodooFX]

OK yes, you can simply give him a partition...

Adding SLOG to a zpool – Dan Langille's Other Diary

I always found answers when I open a new thread

 

[gea]

If you want to overprovision so that the SSD reports 32 GB (without partitioning)

- use a new SSD or do a secure erase
- use Hdat2 HDAT2/CBL Hard Disk Repair Utility to create a HPA/ host protected area

But
even an Intel DC 3700 (quite the fastest Sata SSD) is much slower than an Intel Optane 800P/900P NVMe
even with overprovisioning of the bigger and faster 3700 models

see my benchmarks at https://napp-it.org/doc/downloads/optane_slog_pool_performane.pdf

 

[msg7086]

Using a partition is the same as leaving the rest as reserved space.

 

[mstone]

Using a partition is the same as leaving the rest as reserved space.

...assuming the rest of the drive wasn't used previously or has been trim'd or erased

 

[msg7086]

...assuming the rest of the drive wasn't used previously or has been trim'd or erased

Ah yea, good point. Assuming the drive was fully emptied by firmware before use.