Linux LVM partition to view dm Devices

Linux LVM partition view dm device in linux iostat-d view disk status, there are some entries for the following dm-0, dm-1. device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn sda 0.19 0.57 2.92 341228 1753052 0.27 dm-0 0.56 2.88 334673 dm-1 1729848 0.00 0.00 0.00 0 if LVM is used during partitioning, generally, the dm-N logical volume (LogicVolume) is generated ). it is similar to a common partition, such as sda0. however, it uses the Mapper Device mechanism to virtualize the partition information on PysicalVolume. find the mount point 1.sar-d 1 02:53:06 pm dev tps rd_sec/s wr_sec/s avgrq-sz avgqu-sz await svctm % util 02:53:07 dev8-0 8.00 0.00 72.00 9.00 0.06 7.00 7.00 5.60 02:53:07 PM dev252-0 9.00 0.00 72.00 8.00 0.06 6.22 6.22 02:53:07 PM dev252-1 5.60 0.00 0.00 0.00 0.00 0.00 0.00 display dev252-0, dev252-1, that is, the main device number is dev252 (sda device number is dev8, which is the internal device number generated by linux for the device), the secondary device number is 2.cd/dev/mapper; ll lrwxrwxrwx 1 root 7 Apr 3 yinbeiweb1-root-> .. /dm-0 lrwxrwxrwx 1 root 7 Apr 3 yinbeiweb1-swap_1-> .. /dm-1 to see the soft chain to/dev/dm-N. 3.ll/dev/dm-* brw-rw ---- 1 root disk 252, 0 Apr 3 .. /dm-0 brw-rw ---- 1 root disk 252, 1 Apr 3 .. /dm-1 to see both the master device number is 252