On 11/22/14 01:25, Ed wrote:
avoid dd with SSD drives as the wear leveling will only see the one big block, which defeats the function of wear leveling. You want to use something like scp so the drives wear leveling will work on the many individual files - ie for SSD drives, many small is better than singular big for leveling.
It is not an issue with "one big block". It is that the dd command will write to every block on the device, which has the effect of marking every block as allocated and not available as a target for moving blocks around for wear leveling.
There is a pool of unused/hidden blocks that are used for wear leveling and bad block relocation. Basically the firmware reports the SSD to be smaller than it really is. So, dd is not completely bad. This false size reporting also gives the SSD room to work in, when it really is full.
When you write to the SSD through the filesystem driver, the filesystem keeps track of truly unused blocks and is able to send the TRIM command to the drive to tell the firmware that the block is available for its own internal use.
In Linux it is the "discard" filesystem mount option. -- Mr. Flibble King of the Potato People http://www.linkedin.com/in/RobertLanning _______________________________________________ Discuss mailing list [email protected] https://lists.lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
