[CentOS] Any downside to mount -o noatime?

Fri Feb 11 04:08:02 UTC 2022
Jon LaBadie <jcu at labadie.us>

On Thu, Feb 10, 2022 at 06:22:55PM -0800, Kenneth Porter wrote:
>--On Thursday, February 10, 2022 8:49 PM -0500 Jon LaBadie <jcu at labadie.us>
>> atime updates that occur when {m,c}time are updated add
>> no additional burden.
>Understood. If that's the only time it happened, I would be happy with that.
>> So you are concerned about a single "possible" inode update
>> once a day?
>I'm using BackupPC to do rsync-based backups of all my systems. The
>"incremental" backups look only at size and timestamp changes. The
>less-frequent "full" backups checksum all my files. That means an extra
>write for every file that gets checked.
>I'd love to have a version of relatime that only did the first kind of
>update, when ctime or mtime changed but not when 24 hours had passed.

 From an earlier post:

   "According to the man page for mount, relatime updates atime
    whenever mtime or ctime are updated, or if neither has been
    updated in the last 24 hours."

Are you reading that as "atime gets updated every 24 hrs"?  If so you
are missing "if needed".  I.e. if the file's data blocks have been read.

Checking time-stamps and sizes are not operations that cause atime
updates.  Those are inode operations, not data reads.

Jon H. LaBadie                  jcu at labadie.us