In this section the HDDs are tested under loads typical of the disk subsystem of a server.
As opposed to many other reviewers, we use the Database pattern to measure the performance of the HDD not at a fixed ratio of reads to writes (67% reads to 33% writes) but at 11 points, the percentage of writes changing from 0% to 100% stepping 10%.
As a result, you can choose the HDD that suits the specific ratio of reads to writes of your particular database.
I will discuss three operation modes for three request queue depths. First, the queue is 1 request deep.
The Hitachi HDDs are in the lead at low percentages of writes but the Seagate Barracuda 7200.11 overtakes them as soon as 40% writes. Interestingly, the server-oriented Barracuda ES.2 behaves more conservatively: it is somewhat slow at low percentages of writes but then improves and shows a good performance gain at high percentages of writes. It doesn’t reach the speed of the Barracuda 7200.11, though.
It is just the opposite with the Hitachi HDDs: the server version (Ultrastar) is faster than the desktop version in the Random Write mode (0% read requests).
The HDD from Western Digital is the slowest drive in this test just as you could expect.
Now the requests queue gets longer.
We’ve already seen above that the Seagate drives are good at reordering read requests. This helps them now at low percentages of writes. Take note that the Barracuda 7200.11 is ahead of the Barracuda ES.2 whereas the Hitachi drives are only competitive against the Barracuda 7200.11 in the near-30%-writes zone.
And now the queue depth is the longest.
Every HDD accelerates towards the left part of the diagram, but the Seagate HDDs are still unrivalled. The HDD from Western Digital should be noted for its being almost as fast as the Samsung, which has a higher spindle rotation speed, in nearly every mode.
So, if you are looking for a high-capacity HDD for your database, you can consider the HDDs from Seagate. They feature a good implementation of NCQ which gives them an edge against their opponents. It’s not quite clear why the desktop HDD from Seagate is faster than the server version, but that’s not my problem. :)
The results of this test suggest that Seagate’s drives are going to be superior in every other server test, but we’d better check this out in practice starting with the File-Server pattern.