Originally Posted by
johnw
26.387 TiB , 79 hours, sa177: 56/56/2174
If that 2174 is the average block erase count, and 56 is a number from 100 to 1 that normalizes the block erase count from none (100) to nominal max (1), then Samsung would appear to be specifying about 5000 block erases for their toggle flash (4960 at normalized 1, 5009 at normalized 0 ).
The problem is that if 2174 is the average number of block erases, then the WA is huge. Assuming 64GiB of flash on board, 2174 erases comes to 136TiB, which when compared to the 26.4 TiB written by Anvil's app, results in a ratio of 5.1.
If we take into account the 42GB of static data I have on the SSD, and assume Samsung does NOT do any static data wear leveling (I hope that is not true, but for the sake of argument just go with it), then there is only about 24.9 GiB free for Samsung to erase. 2174 * 24.9 GiB / 1024 = 52.8 TiB , which divided by 26.4 TiB results in a ratio of 2.0. Still seems high for WA.
I cannot make sense of the data. Anyone else have any ideas?
I suppose we will find out if Samsung has terrible write amplification in a few days or weeks -- if the Samsung 470 dies after much lower TiB written than the Intel or Crucial SSDs. Although if that happens, it will be ambiguous whether the early death was a result of high WA, or whether Samsung toggle flash has lower endurance than IMFT flash.
If only I could find a Samsung datasheet for the 470 SSD series SMART attributes. Intel and Micron both document their SMART attributes clearly in a datasheet. But if Samsung has such documentation, I cannot find it (their website is a total catastrophe -- even some of the consumer manual PDF files for the Samsung 470 SSD are broken)
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