For the archive's sake: https://plus.google.com/+GordonMessmer/posts/H5DuyP1LHPU?sfc=false https://plus.google.com/+GordonMessmer/posts/eSe6iNmk1Fs?sfc=false During testing, I found that under CentOS 7.2, the default storage layout for software RAID5 was the worst possible configuration. 512k blocks perform noticeably worse than 64k blocks, and LVM had a tremendous impact as well. After upgrading to CentOS 7.3, which features a newer mpt3sas driver, performance improved significantly. LVM's overhead has decreased to an acceptable level (from my point of view). Because chunk size has a significant impact on performance, I'm going to file an RFE to change the default chunk size for RAID5 and RAID6 volumes.