On a Linux server, there seems to be loss of data at users homes. Where can we find information about the possible loss of data? How to proceed to change the defective Disk (supposing that the filesystem containing the homes is on an independent disk system)?
You have two possible culprits: a user or hardware failure.
Auditing should give you an idea if it's user error or misdeed, though it won't help if you didn't already have any enabled.
SMART status, system logs, and other logging facilities that may be available for your controller should tell you if it's hardware failure. Chances are, though, that you'd have known it by now if the drive was going south.