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Database Patterns

In the Database pattern the drive is processing a stream of requests to read and write 8KB random-address data blocks. The ratio of read to write requests is changing from 0% to 100% with a step of 10% throughout the test while the request queue depth varies from 1 to 256.

You can click these links to view the tabled results:

We will build diagrams for request queue depths of 1, 16 and 256.

We’ve got rather odd results at the shortest queue depth. It differs much from the typical picture like “the HDDs are ranked up according to their caching efficiency yet are overall very similar”. Particularly, the Seagate 7200.11 proves to be better than its successor 7200.12 at any percentage of writes. The new Samsung F3 is good, too, but its performance is not good enough at high percentages of writes to make it a leader. The Samsung F2 is much worse, having very passive firmware algorithms.

The WD drives inexplicably split up in pairs. The single-platter Blue M9 and V1 boast active deferred writing whereas the Black and the Blue A7 draw very similar graphs and deliver higher performance at high percentages of reads. The dual-platter Green model with 16MB cache is faster than its single-platter cousin with twice the amount of cache memory.

Seagate and WD clash when the request queue gets longer, the 7200RPM models from WD still performing in pairs. It is hard to name the winner: WD’s Black and Blue A7 are splendid at reading and their single-platter cousins, at writing. Seagate’s older 7200.11 is still ahead of the 7200.12. The Seagate 7200.11 seems the overall winner to us, but by a very small margin.

As for the rest of the tested products, the Samsung F3 is good at reading but has too unaggressive deferred writing. Its power-efficient cousin behaves in a similar way but slower. The Hitachi 7K1000.C, on the contrary, is no good at reordering read requests. The Seagate LP is excellent at pure reading but very poor under mixed loads.

There are no changes in the WD camp at the longest queue depth: the same pairs are doing their synchronous performances. The Seagate 7200.12 is competing with them now while the 7200.11 falls behind. The Seagate LP looks good, outpacing both the Hitachi 7K1000.C and the Samsung F3. The latter two are downright poor in this test. The Samsung F2 is not any good, either. Its firmware is not meant for server loads.

 
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