Calendar Events¶
Introduction and Format¶
Certain tasks, for example pruning and garbage collection, need to be performed on a regular basis. Proxmox Backup Server uses a format inspired by the systemd Time and Date Specification (see systemd.time manpage) called calendar events for its schedules.
Calendar events are expressions to specify one or more points in time. They are mostly compatible with systemd's calendar events.
The general format is as follows:
[WEEKDAY] [[YEARS-]MONTHS-DAYS] [HOURS:MINUTES[:SECONDS]]
Note that there either has to be at least a weekday, date or time part. If the weekday or date part is omitted, all (week)days are included. If the time part is omitted, the time 00:00:00 is implied. (e.g. '2020-01-01' refers to '2020-01-01 00:00:00')
Weekdays are specified with the abbreviated English version: mon, tue, wed, thu, fri, sat, sun.
Each field can contain multiple values in the following formats:
comma-separated: e.g., 01,02,03
as a range: e.g., 01..10
as a repetition: e.g, 05/10 (means starting at 5 every 10)
and a combination of the above: e.g., 01,05..10,12/02
or a * for every possible value: e.g., *:00
There are some special values that have a specific meaning:
Value |
Syntax |
|---|---|
minutely |
*-*-* *:*:00 |
hourly |
*-*-* *:00:00 |
daily |
*-*-* 00:00:00 |
weekly |
mon *-*-* 00:00:00 |
monthly |
*-*-01 00:00:00 |
yearly or annually |
*-01-01 00:00:00 |
quarterly |
*-01,04,07,10-01 00:00:00 |
semiannually or semi-annually |
*-01,07-01 00:00:00 |
Here is a table with some useful examples:
Example |
Alternative |
Explanation |
|---|---|---|
mon,tue,wed,thu,fri |
mon..fri |
Every working day at 00:00 |
sat,sun |
sat..sun |
Only on weekends at 00:00 |
mon,wed,fri |
-- |
Monday, Wednesday, Friday at 00:00 |
12:05 |
-- |
Every day at 12:05 PM |
*:00/5 |
0/1:0/5 |
Every five minutes |
mon..wed *:30/10 |
mon,tue,wed *:30/10 |
Monday, Tuesday, Wednesday 30, 40 and 50 minutes after every full hour |
mon..fri 8..17,22:0/15 |
-- |
Every working day every 15 minutes between 8 AM and 6 PM and between 10 PM and 11 PM |
fri 12..13:5/20 |
fri 12,13:5/20 |
Friday at 12:05, 12:25, 12:45, 13:05, 13:25 and 13:45 |
12,14,16,18,20,22:5 |
12/2:5 |
Every day starting at 12:05 until 22:05, every 2 hours |
*:* |
0/1:0/1 |
Every minute (minimum interval) |
*-05 |
-- |
On the 5th day of every Month |
Sat *-1..7 15:00 |
-- |
First Saturday each Month at 15:00 |
2015-10-21 |
-- |
21st October 2015 at 00:00 |
Differences to systemd¶
Not all features of systemd calendar events are implemented:
no Unix timestamps (e.g. @12345): instead use date and time to specify a specific point in time
no timezone: all schedules use the timezone of the server
no sub-second resolution
no reverse day syntax (e.g. 2020-03~01)
no repetition of ranges (e.g. 1..10/2)
Notes on Scheduling¶
In Proxmox Backup, scheduling for most tasks is done in the proxmox-backup-proxy. This daemon checks all job schedules every minute, to see if any are due. This means that even though calendar events can contain seconds, it will only be checked once per minute.
Also, all schedules will be checked against the timezone set in the Proxmox Backup server.