As we have seen, a potential drawback of SSDs is that the underlying flash memory can wear out. For example, for the SSD in Figure 6.14, Intel guarantees about 128 petabytes (128 × 10¹⁵ bytes) of writes before the drive wears out. Given this assumption, estimate the lifetime (in years) of this SSD for the following workloads:

A. Worst case for sequential writes: The SSD is written to continuously at a rate of 470 MB/s (the average sequential write throughput of the device).

B. Worst case for random writes: The SSD is written to continuously at a rate of 303 MB/s (the average random write throughput of the device).

C. Average case: The SSD is written to at a rate of 20 GB/day (the average daily write rate assumed by some computer manufacturers in their mobile computer workload simulations).

Figure 6.14

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Reads Sequential read throughput Random read throughput (IOPS) Random read throughput (MB/s) Avg. sequential read access time 550 MB/s 89,000 IOPS 365 MB/s 50 μs Writes Sequential write throughput Random write throughput (IOPS) Random write throughput (MB/s) Avg. sequential write access time 470 MB/s 74,000 IOPS 303 MB/s 60 μs