somethingIf you need cron jobs/sheduledtasks function than it is important to understand few things,very often just because cron job is not created properly(expecually when multiple crons are added)
it will happen that your hosting account will constantly use all CPU/RAM/IO alocated to your account and this will lead to very slow response of anything hosted on your account..
In case you have multiple crons running at low frequency(5-10 minutes),in beginning you will not experience any changes but after some time your account will load all resources
allocated to your account and became slow. So,to prevent this(because we saw this is very often case)we decide to explain few things and provide tips how you can use cron jobs without
killing perfomance. First,there is no need to execute crons at frequency lower than 5 or even 10 minutes,most hosting provider doesn't allow lower cron job frequency than 15 minutes
and in case when user add cron job and set it to run at any frequency lower than 15 minutes,they automatically execute these crons at 15 minutes. WE DON'T DO THIS..if you set 5 minutes cron than it will run every 5 minutes...Why you don't have to use low frequency crons? Because if in 5 minutes 10 users subscribe at your website,if you set cron executed every 1 minute or cron executed every 5 minutes you will get same results ,at the end after five minutes you will have 10 queries processed...but when you multiple websites on same account and multiple crons,if you set 5 cron executed every minute...in practice it means crons on your account never stop..because after few hours it will result that new cron is starting while 1 or 2 are still working...and if you didn't add
>/dev/null 2>&1 at the end of your cron command your crons will generate huge number of e-mails whic will put even more load on your account. So ,except in special case,you don't have to use lower frequency crons than 5 or 10 minutes and this will not change results,in practice cron executed in 10 minutes will still process all queries added in 10 minutes. Also,if you don't need e-mail notification than add
>/dev/null 2>&1 at the end of every command,this will disable email notification....fro example it would look like
Also,setting external crons(i.e web crons)will lead to same result,it doesn't metter from where cron is trigered,it is still loaded and executed on your account,we do scan all activity ,includeing cron jobs and when noticed we will send you notification and instruction how to fix that without affecting end results but our scripts can only detect abnormal behave or syntax error not semantics or logic behind,so it is up to you to make sure you use resources at best way.At the end,you can't(in most cases) affect other users and server in global,because resources are allocated to every individual account but it is in our interst that every user get most from their accounts and with little tweaking you can avoid upgrade or get better perfomanse...