Linux LVM partition view DM device

Linux LVM partition view DM device

When iostat-d view disk status in Linux, some of the dm-0,dm-1 entries are as follows.

Device:tps kb_read/s kb_wrtn/s Kb_read Kb_wrtn

SDA 0.19 0.57 2.92 341228 1753052

dm-0 0.27 0.56 2.88 334673 1729848

Dm-1 0.00 0.00 0.00 876 0

Dm-n logical volumes (Logicvolume) are typically generated if LVM is used in the partitioning. It is similar to a partition of a normal partition such as a sda0. It is only using the Mapper device mechanism to virtual the partition information on the Pysicalvolume.

Find the mount point for Dm-n

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 PM 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 5.60

02:53:07 PM dev252-1 0.00 0.00 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 that Linux generates for the device), the secondary device number is 0,1

2.cd/dev/mapper; ll

lrwxrwxrwx 1 root root 7 Apr 3 16:12 yinbeiweb1-root. /dm-0

lrwxrwxrwx 1 root root 7 Apr 3 16:12 yinbeiweb1-swap_1. /dm-1

You can see the soft chain on the/dev/dm-n.

3.ll/dev/dm-*

BRW-RW----1 root disk 252, 0 APR 3 16:12. /dm-0

BRW-RW----1 root disk 252, 1 APR 3 16:12. /dm-1

You can see both the main device number is 252

• This article is from: Linux Learning Tutorial Network

Linux LVM partition view DM device