How to erase a SSD to restore factory performance from Linux
Following findings that one of our Samsung 840 Pro SSDs is the most likely cause for extremely poor performance of an mdraid-1 array I'd like to erase the respective SSD. Maybe this will restore a reasonable level of performance.
So I'd like to mdadm --manage --fail and --remove on each of the partitions on the respective SSD and then erase it and re-add it into the array.
What would be an advisable way to erase the SSD from Linux to restore factory performance?
By the way, hdparm indicates that both drives are frozen:
Master password revision code = 65534
not expired: security count
supported: enhanced erase
2min for SECURITY ERASE UNIT. 2min for ENHANCED SECURITY ERASE UNIT.
Maybe this is because they are now part of an md array.
The only problem was that my SSDs were frozen. To unfreeze, I had to remove the md partitions of the drive in question from the md devices (mdadm --manage /dev/mdx --fail /dev/sdy), hot remove them (--manage...--remove) and remove the cage from the bay. The requirement is a physical hot swap setup.
Off topic but interesting: the secure erase of the Samsung SSD has helped tremendously. The read speed increased rougly 2.5 times and the write speed across the array...well...from a pitiful 5-13MB to about 130-140MB/s (the baseboard is a sata2 so the max theoretical speed is about 240MB/s).