HPA Size Table

SSD vendor size (GB)	Desired capacity (GB)	Overprovisioned %	HPA Sectors
256/240	220	14/8	429687500
512/480	460	10/4	898437500
1024/960	920	10/4	1796875000
2048/?	1900	7/?	3710937500

In theory, the number of sectors to set up can be calculated as

x = s*10^9/512

where s is the desired size in GB (base 1000).

Automatically Resize SSD with Script

There is a script on exampleclu which automatically erases and resizes an SSD. This script works for Kingston and Samsung SSDs only, at the moment. For Intel SSDs, use the manual method.

bash /usr/local/scripts/setup_new_ssd.sh --device /dev/sdX --size auto --yes

The size parameter sets the new size in GBs. If you use auto, the SSD will be resized according to the table above (recommended). The device must be physically removed and inserted (power-cycled) to the PC afterwards.

Steps to Set up HPA Manually

Kingston and Samsung SSDs

We will assume that the device to modify is available at /dev/sde.

1. make sure the device does not contain any data!
2. secure erase the drive

   hdparm --user-master u --security-set-pass foo /dev/sde
   hdparm --user-master u --security-erase foo /dev/sde

3. set up HPA according to the table above, HPA size is set up in sectors

   hdparm -Np<sectors> --yes-i-know-what-i-am-doing /dev/sde

4. check the result

   hdparm -N /dev/sde

5. delete and re-scan the device

   echo 1 > /sys/block/sde/device/delete
   # use lsscsi or dmesg to find proper scsi host number
   echo "- - -" > /sys/class/scsi_host/host<X>/scan

6. check out the resized disk

   fdisk - l /dev/sde

Intel SSDs

Intel SSDs are different in that you cannot use hdparm to set up HPA. Instead, Intel has a special management tool called isdct which is only available on exampleclu right now. To set up HPA, follow these steps:

1. First, you must identify the proper Intel SSD, the tool uses different identifiers than /dev/sdX. Call

   isdct show -intelssd

   and look for Index: <number> under the disk with the right S/N.
2. Call

   isdct set -intelssd <index> MaximumLBA=$(( <HPA sectors from table above> - 1 ))

3. Call

   echo 1 > /sys/block/sdX/device/delete

4. Power-cycle the device.