Exadata: how to backup system before upgrade rpm packages? My PCI scanned found some vulnerabilities on my Exadata. I must upgrade glibc package. 

Before that I want to backup the system not to ruin something. By which tool can I backup OS?

I used acronis, clonezilla but maybe I have old version , because they are not able to backup the system.

Please, give me any advice.
Answer is the following:
Create LVM Snapshot-Based Backup for your OS.
Refer below link in steps to perform the same. 
https://docs.oracle.com/cd/E50790_01/doc/doc.121/e51951/db_server.htm#DBMMN22020 
2 Maintaining Database Servers of Oracle Exadata Database Machine 
Section: 
Creating a Snapshot-Based Backup of Oracle Linux Database Server