the first method:
First check the system disk partition on which to hang, and then view the time this partition created with dumpe2fs, you can find out the time server system installation. ()
# dumpe2fs /dev/sda3|grep -i created
dumpe2fs 1.42.9 (28-Dec-2013)
Filesystem created: Mon Apr 1 19:41:00 2019
The second method:
View / boot or boot time grub directory lost + found directory under the directory can be generally seen
