Margaret, were you using EBS Provisioned IOPS SSD or EBS General Purpose SSD for your second test when you striped 3 x 12.5TB volumes?   My results for i3.8xlarge using 2 of the 4 available Ephemeral NVME drives I striped and tested with rhel_iotest.sh.   RESULTS ------- INVOCATION:  rhel_iotest -t /saswork   TARGET DETAILS directory:    /saswork df -k:        /dev/md0       3708852856 134243856 3574609000   4% /saswork mount point:  /dev/md0 on /saswork type xfs (rw,noatime,nodiratime,seclabel,attr2,nobarrier,inode64,logbufs=8,sunit=1024,swidth=2048,noquota) filesize:     182.95 gigabytes   STATISTICS read throughput rate:   243.40 megabytes/second per physical core write throughput rate:  95.27 megabytes/second per physical core     ********* ALL ERRORS & WARNINGS ********* <<WARNING>>  insufficient free space in [/saswork] for FULL test. <<WARNING>>       - smaller stack size and # of blocks will be used. ***************************************** ... View more