Is it possible to put a regular hard drive on the Server?

Question

System administration

Good day to all ... Descriptions: there is a server on which Centos 6.8 with WHM & CPanel is installed, it will get off on RAID 1 (dm-*) 1 TB. Is it possible to put a regular HDD 2.5 for backup? Mount to the root directory
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fdisk -l

Disk /dev/sda: 1000.2 GB, 1000171331584 bytes
255 heads, 63 sectors/track, 121597 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: 0x0004faa0

   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      121598   976216064   8e  Linux LVM

Disk /dev/mapper/vg_srv20-lv_root: 53.7 GB, 53687091200 bytes
255 heads, 63 sectors/track, 6527 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: 0x00000000


Disk /dev/mapper/vg_srv20-lv_swap: 25.4 GB, 25375539200 bytes
255 heads, 63 sectors/track, 3085 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: 0x00000000


Disk /dev/mapper/vg_srv20-lv_home: 920.6 GB, 920578424832 bytes
255 heads, 63 sectors/track, 111920 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: 0x00000000

Answer 1

Yes, you can install a non-server disk.
Moreover, this is often practiced even in very serious offices and specifically for backups
https://habrahabr.ru/post/237887/
The biggest difference between server and desktop disks is ERC / TLER.
This means that the server disk reports errors as early as possible,
while the desktop one tries and tries to recover on its own.
For backups, this is not an essential moment.
On the second question: ask different questions - separately. Don't mix everything up.

Answer 2

yes, any disk can be installed, if not some kind of enterprise raid that does not accept left disks,
home does not need to be reduced
, you just need to transfer part of the data to home and make symlinks, it's simple, fast and safe