I want to set an overprovisioning area for a Samsung 850 EVO 500GB that has previously been in use by Windows and now in use by Linux. The disk is not-empty. I have left the last 10% of the disk unformatted. It is not clear to me what requirements need to be met before this 10% can be used effectively by the ssd controller.Q. Can I overprovision the disk without erasing the whole drive? http://www.linux-magazine.com/Issues/2016/187/SSD-tuning seems to suggest the disk needs to be erased completely, but then I would lose al my data. It lists two methods:Method 1:set up a host-protected area (HPA) with hdparm. To create an HPA, you'll need to delete all the blocks on the SSD. (..) if the device has already been used, you need to restore this state with a secure erase or manual trim (depending on the SSD). Typing the following:hdparm -Np number_of_sectors /dev/sdbsets up the host-protected area.Method 2:With the second method, you just leave an area on the SSD unpartitioned and create partitions for, say, only 90 percent of the disk's capacity. In this case as well, you need to perform a secure erase up front if the SSD was previously in use.I was thinking about the following steps:trim / zerofill (?) the last 10% of the space via blkdiscard,hdparm -Np to first sector of those last 10%rebootThis blogpost describes the hdparm approach, but i see no mention of erasure. Is erasue actually needed?
Overprovisioning ssd that has been in use already
ssd;hdparm