On 15/10/14 14:12, Peter Wu wrote: > [ blkdiscard vs hdparm --security-erase] How does this compare. The goal is to erase the contents of an previously used SSD to improve performance. > When you use blkdiscard, the SSD (assuming a SATA SSD) will receive an ATA TRIM command, whereas hdparm --security-erase will issue an ATA SECURITY ERASE UNIT command. What the drive then actually does is dependant on the implementation details of that particular SSD's firmware. In general, I would expect the performance gain from TRIMing the entire drive to be either the same-as, or possibly less-than the gain from SECURITY ERASE. For a sane firmware implementation I'd expect them to have the same effect on performance. Firmware implementations are not always sane. Personally, unless I want to keep some of the data on the drive, I use hdparm --security-erase, as I feel that this is most likely to reset the drive to its as-new state (or at least close to it), but the real answer is that it depends on the drive, so if you really want to know, you'll have to do some performance tests on your drive(s). Tim. -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
