Mount and Unmount hdd with account backups

Hy guys, i got a big dilema cuz i never made this tipe of action and i dont fiind any certain answear. I got 2 disk on my Centos 6 server, on the 1000gb sda is Centos 6 / Cloudlinux, WHM, WhmSonic Websites ...etc, the secand sdb i use it to store backups made by WHM, so i made full backup of all websites/accounts on the sdb and i whant to take off from server boath hdds and add 512GB SSD, make a fresh install Centos, WHM ...etc after to add back the sdb hdd where ar all the websites/accounts backup, move them to the new ssd and restore them. I know there ar some commands mount and unmount but i whant to be sure i`m not loosing data from the sdb when i mount it, so please tell me the full command to mount the sdb hdd mount -t ex3 /dev/sdb /home2 ? Thank you, i truly apriciate if you cand help me root@d1 [~]# fdisk -l Disk /dev/sdb: 146.8 GB, 146815733760 bytes 255 heads, 63 sectors/track, 17849 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x340233b7 Device Boot Start End Blocks Id System /dev/sdb1 1 17850 143374708+ 83 Linux Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000629b0 Device Boot Start End Blocks Id System /dev/sda1 * 1 64 512000 83 Linux Partition 1 does not end on cylinder boundary. /dev/sda2 64 1109 8388608 83 Linux /dev/sda3 1109 2153 8388608 82 Linux swap / Solaris /dev/sda4 2153 121602 959472344 5 Extended /dev/sda5 2153 121602 959470592 83 Linux