Can enabling a RAID controller's writeback cache harm overall performance?
- by Nathan O'Sullivan
I have an 8 drive RAID 10 setup connected to an Adaptec 5805Z, running Centos 5.5 and deadline scheduler.
A basic dd read test shows 400mb/sec, and a basic dd write test shows about the same.
When I run the two simultaneously, I see the read speed drop to ~5mb/sec while the write speed stays at more or less the same 400mb/sec. The output of…