We recently found the disk io on LVM partition is very slow on KNL 7250 with CentOS7.3. The disk is 800G SSD with SATA6, xxpsl is installed and MCDRAM is set to cache mode. Any thing wrong?
/dev/sda1: <= non LVM
Timing buffered disk reads: 980 MB in 3.00 seconds = 326.28 MB/sec
/dev/sda2: <= LVM
Timing buffered disk reads: 490 MB in 3.00 seconds = 163.21 MB/sec
and disk layout
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Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 1562822655 780361728 8e Linux LVM
Disk /dev/mapper/cl-root: 53.7 GB, 53687091200 bytes, 104857600 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/mapper/cl-swap: 4294 MB, 4294967296 bytes, 8388608 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/mapper/cl-home: 741.1 GB, 741104156672 bytes, 1447469056 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
