Preparing for the First Test

Before we start the test, it is essential to put the disk into a clean, factory-fresh state so that its performance and behaviour is not impacted by any previous history.  To achieve this, we will secure-erase it: this wipes any data and resets the flash all at once.  On our Linux system the commands are:

# hdparm --user-master u --security-set-pass abcd /dev/sdb
# hdparm --user-master u --security-erase abcd /dev/sdb

This takes around 20 seconds and puts everything back to new.  We will then label and partition the disk.  For this first stage of testing, we will leave approximately 9% of the SSD unallocated, which will enable the controller to use it for over-provisioning.  This is towards the upper end of the recommended 7-10% range, and will assist with house-keeping functions such as wear-levelling, as well as providing spare capacity for when blocks eventually start to fail.  So the output from 'parted' is:

# parted /dev/sdb
(parted) p
Model: ATA Samsung SSD 850 (scsi)
Disk /dev/sdb: 1024GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Number  Start   End    Size   File system  Name  Flags
 1      1049kB  934GB  934GB  xfs          data

Finally, we will format the partition with XFS and mount it to '/data’:

# mkfs -t xfs -l size=96m -i maxpct=1 -f /dev/sdb1

We're all set to start!