I performed test on disk with firmware DXM04B0Q. When you want to buy this disk now you probably have firmware DXM05B0Q or DXM06B0Q.
Problem is, both new firmwares has the same performance degradation issue.
Since my first blogpost we bought about 100 disks and after few months we're started observing some problems on database servers. Servers and disks was very slow, we are talking about 10 MB/s continuous write speed.
First of all, we repeat our direct disk test, then we started to test disk with different filesystems.