Is postgresql the only thing using the disk space/partition? Have you considered running a cron job to parse df output to "trigger" a delete when disk usage gets to a set threshold? and thus also account for any unexpected non-postgresql disk usage. I would also think you would want to consider the size of the old stored data when deciding how many records to delete.
To give you an idea of the figures we are talking about: Say we have a 250 GB disk. Normally we would use about 4-8 GB of database.
Given that you normally have 4-8GB of data and you have trouble when a fault/error causes an excess of 200GB I would also think about triggering a stop recording under those conditions. If it takes 200GB of data to automate a data purging then the purging of *all* old records is going to give you a short time of extra space unless you start purging the beginning of the current erroneous recording. I am thinking that a cron job that will email/page/sms you when it hits 50% disk usage would be a better solution that would simply give you a heads up to find and fix the fault causing the excess usage. -- Shane Ambler pgSQL (at) Sheeky (dot) Biz Get Sheeky @ http://Sheeky.Biz ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
