SSD 6= SSD – An Empirical Study to Identify Common Properties and Type-specific Behavior

Solid-state disks are promising high access speed at low energy consumption. While the basic technology for SSDs – flash memory – is well established, new product models are constantly emerging. With each new SSD generation, their behavior pattern changes significantly and it is therefore difficult to make out characteristics for SSDs in general. In this paper, we accomplish empirical, database-centric performance measurements for SSDs, explain the results, and try to derive common characteristics. By comparing our measurement results, we detect no ground truth valid for all solid-state disks. Furthermore, we show that a number of prevalent assumptions about SSDs, which several SSD-specific DBMS optimizations are based on, are questionable by now. As a consequence of these findings, tailor-made DBMS algorithms for specific SSD types may be unsuitable and optimal use of SSD technology in an DBMS context may require careful design and rather adaptive algorithms.