Massive number of sessions

my personal page shows a massive numer of sessions. Apparently my connected devices don't disconnect properly. I can trash these sessions by hand - but is there also a way to disconnect them automatically / in batch mode?
Thanks in advance

How many sessions do you have per device?

hundreds of them --often many many on the same day, also. Up to 4 months back with "last activity

Is your cronjob running properly? Check on your admin page when it was run for the last time. I'm not sure if this is handled directly by owncloud or if the sessions are killed by a php clean-up routine (also cronjob). Did you check your logfiles?

That might be the reason. My personal page states that the last cron job was run 3 months ago. So there is a problem, but I cannot figure it out.

I set up the crontab-file using "sudo -u crontab -u www-data -e" www-data as

1/1 * * * * usr/bin/php -f /var/www/cloud/cron.php > /var/www/cloud/cron_log

so it should give alogfile, which - however- doesn't show up.
So it looks like cron isn't running at all.

How can I check that?

Thanks in advance

Is there a missing slash (/) in front of the usr/bin/php or is this just a copy and paste error?

Thanks. That was just a typo. Stills doesn't work.

It always worth to run the command from command line instead of adding it directly to the cron tab to make sure it is doing and working as expected.

Is this a typo, it should be:
sudo -u www-data crontab -e

Running the cronjob every minute is probably not required and you might get problems if the cron jobs runs for more than one minute. Start with the recommended value of 15 minutes and decrease slowly if required.

You log the output of the command, did you have a look into the file?

FWIW, I have the same issue (on a hosted server, no access to command line).
There are hundreds of active sessions, between 15 and 12+ months old. They might come from owncloud clients (Windows and Android), not 100% sure.

is there a way to close/disconnect them all?