reformat#

data be gone#

it goes without saying that all formatting actions are pretty destructive for the data on the disk. the format commands will wipe a drive completely with no hope of recovering the data.

but still, don’t use this if sanitize disks.

this needs a hba, a raid card will eat whatever instructions you send and spits them back out in his image, this is what arrives at the disk

raid card modes like jbod or passthrough often say then won’t intercept commands, tried it with the cards i have but i could not get it to work. some raid cards can be flashed to use a hba firmware and enable passthrough, but that’s a story for another time and place.

determining the current sector size#

by using sg_format.exe#

in this syntax sg_format.exe is safe to use. it will not destroy data

sg_format.exe PD3
    NETAPP    X371_S164A960ATE  NA54   peripheral_type: disk [0x0]
      Unit serial number: S5JENE0R504188
      LU name: 5002538b0156bb30
Mode Sense (block descriptor) data, prior to changes:
  Number of blocks=1875385008 [0x6fc81ab0]
  Block size=520 [0x208]
Read Capacity (10) results:
   Number of logical blocks=1875385008
   Logical block size=520 bytes
No changes made. To format use '--format'. To resize use '--resize'

current blocksize:

Logical block size=520 bytes

by using smartmontools#

for usage of smartmontools see here

you’ll need to use either smartctl.exe -a or smartctl.exe -x to enable this output.

you’re looking for the lines starting with:

Logical block size:
- size presented to the operating system
Physical block size:
- native size the disk uses

if the logical and physical sizes match only physical will be shown.

512byte logical, 4k physical:

Logical block size:   512 bytes
Physical block size:  4096 bytes

4k logical, 4k physical:
- ```
Physical block size:  4096 bytes
```

520byte logical, 4160byte physical:

Logical block size:   520 bytes
Physical block size:  4160 bytes

4160byte is seldom mentioned but straightforward: just like 4k native drives can use 512byte, the same goes for 520byte: here to native size equivalent is 4160byte.

you can reformat to this as well, which is mostly useless in the context here.

by using storcli#

storcli hangs easily, this includes when 520byte disks are attached. i recommond the 2 previous options.

calling storcli what he argument /c0 show will have the sector size under the heading SeSz.

-------------------------------------------------------------------------
EID:Slt DID State DG       Size Intf Med SED PI SeSz Model            Sp
-------------------------------------------------------------------------
0:12      1 JBOD  -   13.972 TB SAS  SSD -   -  512B X670_S164315TATE -
3:1       4 JBOD  -  894.253 GB SAS  SSD -   -  4 KB X371_S164A960ATE -
-------------------------------------------------------------------------

reformatting to a different blocksize#

we have the option to reformat to 512byte or 4k. you can either check the datasheet of the drive or trust what smartmontools says.

4k (preferred)
- the modern standard
- you can theorycraft how this is faster, in reality this you won’t notice even in benchmarks
512byte (fallback)
- when your controller or expander does not support 4k
- for legacy boot options

changing to 4k#

this uses switch --size=4096

>sg_format.exe  --format --size=4096 PD3
    NETAPP    X371_S164A960ATE  NA54   peripheral_type: disk [0x0]
      Unit serial number: S5JENE0R504188
      LU name: 5002538b0156bb30
Mode Sense (block descriptor) data, prior to changes:
  Number of blocks=1875385008 [0x6fc81ab0]
  Block size=520 [0x208]

A FORMAT UNIT command will commence in 15 seconds
    ALL data on PD3 will be DESTROYED
        Press control-C to abort

A FORMAT UNIT command will commence in 10 seconds
    ALL data on PD3 will be DESTROYED
        Press control-C to abort

A FORMAT UNIT command will commence in 5 seconds
    ALL data on PD3 will be DESTROYED
        Press control-C to abort

Format unit has started
Format unit in progress, 6.86% done
Format unit in progress, 13.85% done
Format unit in progress, 20.84% done
Format unit in progress, 27.84% done
Format unit in progress, 34.83% done
Format unit in progress, 41.82% done
Format unit in progress, 48.81% done
Format unit in progress, 55.81% done
Format unit in progress, 62.80% done
Format unit in progress, 69.79% done
Format unit in progress, 76.78% done
Format unit in progress, 83.78% done
Format unit in progress, 90.77% done
Format unit in progress, 97.76% done
FORMAT UNIT Complete

changing to 512 byte#

this uses switch --size=512

>sg_format.exe  --format --size=512 PD6
NETAPP    X371_S164A960ATE  NA54   peripheral_type: disk [0x0]
Unit serial number: S5JENE0R502224
LU name: 5002538b01564070
Mode Sense (block descriptor) data, prior to changes:
Number of blocks=1875385008 [0x6fc81ab0]
Block size=520 [0x208]

A FORMAT UNIT command will commence in 15 seconds
ALL data on PD6 will be DESTROYED
Press control-C to abort

A FORMAT UNIT command will commence in 10 seconds
ALL data on PD6 will be DESTROYED
Press control-C to abort

A FORMAT UNIT command will commence in 5 seconds
ALL data on PD6 will be DESTROYED
Press control-C to abort

Format unit has started
Format unit in progress, 6.93% done
Format unit in progress, 14.00% done
Format unit in progress, 21.07% done
Format unit in progress, 28.13% done
Format unit in progress, 35.19% done
Format unit in progress, 42.26% done
Format unit in progress, 49.32% done
Format unit in progress, 56.38% done
Format unit in progress, 63.45% done
Format unit in progress, 70.50% done
Format unit in progress, 77.56% done
Format unit in progress, 84.62% done
Format unit in progress, 91.69% done
Format unit in progress, 98.75% done
FORMAT UNIT Complete

back to 520 or 4160#

dumb idea unless you have a very specific reason. windows will not be able to write data t these disks.

you can use --size=520 and --size=4160 should you need have a need to. i haven’t tested if the system the drive originally came will accept them again. i’d say chances are slim.