Hello, I have one problem when a massive random write operation is launched and virtual drive has write-back enabled. Reads are slow while flushing cache. I was able to reproduce it when I launch two sqlio in parallel: -one sqlio process writing random (-b8 -o1)
-one sqlio process read random (-b8 -o1)
Drive group: 8xR1 1TB 7.2k, direct io, disk cache disabled. LSI model: 9280 4i4e firmware 12.15.0-0189
Virtual drive with write-back is enabled: reads iops/sec: 20, Avg_Latency(ms): 48, Max_Latency(ms): 716 writes iops/sec: 1346, Avg_Latency(ms): 0, Max_Latency(ms): 0 Virtual drive with write-Throught is enabled: reads iops/sec: 142, Avg_Latency(ms): 6, Max_Latency(ms): 26 writes iops/sec: 106, Avg_Latency(ms): 8, Max_Latency(ms): 35 Is posible slowdown writes having write-back enabled? Writes are fast (wb), but read latency is really high. I tested flush interval (1sg - 60sg) but with no sucess.