A problem over the last weekend when the clocks went forward, showed there was a need\u00a0to do resolve to how the GMT cron jobs should work on a few servers working together (when timing is important).<\/p>\n
For a couple of years I simply changed the hour in the The first step was to put the cron table into GMT hours (i.e. ensure all jobs would run as GMT as normal). The next step was to introduce for the “morning run” of work, a check to sleep for an hour if the server is in British Summer Time (BST). We can find this out by using:<\/p>\n Which can give an output like this:<\/p>\n All we want is the local time zone daylight savings flag and then do something if that is BST. We can get just this flag if we use the %Z parameter to the Here’s a little bit of code to wait if we’ve run in GMT but need to wait an hour due to BST:<\/p>\n This is then done for the afternoon run and the same again for the evening run.<\/p>\n Note this may cause a problem if multiple scripts check this as they may get serial delays. This works best if you have one main job, and the check is done once.<\/p>\n So now the script will check if it is GMT or BST and wait an hour if BST. <\/p>\n","protected":false},"excerpt":{"rendered":" A problem over the last weekend when the clocks went forward, showed there was a need\u00a0to do resolve to how the GMT cron jobs should work on a few servers working together (when timing is important). For a couple of … Continue reading crontab <\/code>on each server and left it at that, but alas this is open to error across multiple severs, so I decided to do something about it.<\/p>\ndate<\/pre>\n
Mon Apr 1 12:17:55 BST 2013<\/pre>\n
date<\/code> command.<\/p>\n# --- GMT checking - we assume run in GMT timeframe\r\nSLEEPPERIOD=3600\r\nGMTBST=`date '+%Z'`\r\nif [ $GMTBST == BST ]\r\nthen\r\n # must be in summertime, so wait an hour\r\n echo \"Found the date has $GMTBST. Sleeping for $SLEEPPERIOD seconds ...\"\r\n sleep $SLEEPPERIOD\r\nelse\r\n echo \"Not BST, carrying on\"\r\nfi<\/pre>\n