This is to report whole 6.7RC got slow disk performance, I have setup as below   - 3 disk connect to LSI HBA - 1 SSD connect to onboard SATA - each disks have only one 24GB file for testing - same issue reproduce on 3 different PC platform   Test by cat /mnt/disk(x)/xxxx > /dev/null   In 6.6.7, even 3 disk read at same time, throughput was normal      But after 6.7RC, even onlyone disk access, throughput already drop.