Experimental Physics and
Industrial Control System

Rebecca Harding (she/her)

Controls Software Engineer

Central Laser Facility

Science and Technology Facilities Council

rebecca.harding at stfc.ac.uk

01235 445129

Hi Rebecca,

You could do this by configuring the storage URLs for a PV via policies.py, with the last entry as "blackhole://localhost"; then the ETL will delete the data under the specified conditions.

Some of the docs for putting together the URLs are here https://slacmshankar.github.io/epicsarchiver_docs/api/edu/stanford/slac/archiverappliance/PlainPB/PlainPBStoragePlugin.html

Here's a bit of policies.py where for certain PVs we delete the data after 6 months.

        if userPolicyOverride == 'some-example-policy':

            keep_months = 6

        [...]

        # hold - gather is the minimum number of files that will be retained

        # Empirically it seems to hold one less than requested, so we add two.

        hold = keep_months + 2

        gather = 1

        sts_url = 'pb://localhost?name=STS&rootFolder=${ARCHAPPL_SHORT_TERM_FOLDER}&partitionGranularity=PARTITION_15MIN&consolidateOnShutdown=true'

        mts_url = 'pb://localhost?name=MTS&rootFolder=${ARCHAPPL_MEDIUM_TERM_FOLDER}&partitionGranularity=PARTITION_DAY&hold=2&gather=1'

        lts_url = 'pb://localhost?name=LTS&rootFolder=${ARCHAPPL_LONG_TERM_FOLDER}&partitionGranularity=PARTITION_MONTH&hold=%d&gather=%d' % (hold, gather)

        blackhole_url = 'blackhole://localhost'

        data_stores = [sts_url, mts_url, lts_url, blackhole_url]

Kind regards,

Andy

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Rebecca Harding - STFC UKRI via Tech-talk <tech-talk at aps.anl.gov>
Sent: Monday, August 1, 2022 10:25
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: EPICS Archiver Appliance - Auto-delete Old Data

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