Hourly cronjob in PBS probably wakes up drives

[TheDJ]

I am running PBS as a VM on Unraid, which works perfectly so far. My main datastore is mapped according to the tutorial at https://forum.proxmox.com/threads/h...ofs-to-passthrough-shares.120271/#post-522318 via the virtiofs driver.
The mapped drives are configured to go to sleep after no activity.
The actual VM resides on an SSD ZFS pool.

In the past few days, I have noticed that they wake up consistently every hour.
In the syslog I have identified the following entries which could match this behavior:

Mar 31 08:17:01 pbs CRON[4752]: pam_unix(cron:session): session opened for user root(uid=0) by (uid=0)
Mar 31 08:17:01 pbs CRON[4753]: (root) CMD (cd / && run-parts --report /etc/cron.hourly)
Mar 31 08:17:01 pbs CRON[4752]: pam_unix(cron:session): session closed for user root

I am not entirely sure if this is the case, but in an effort to identify the issue, I would like to verify if this is the case.

To my surprise, the /etc/cron.hourly is completely empty, so I am not sure if that could be the issue.

Is it safe to deactivate the cd / && run-parts --report /etc/cron.hourly in the crontab or am I breaking something else through that?

 

[LukasInCloud]

Сron jobs can definitely cause periodic drive wake-ups. Even if /etc/cron.hourly/ is empty, the run-parts command itself may still trigger some filesystem access.Modify /etc/crontab to log output:

17 * * * * root cd / && run-parts --report /etc/cron.hourly >> /var/log/cron_hourly.log 2>&1

Then check the log after an hour. If nothing crucial runs, you can comment it out safely.