From 291b786076fda3c288c812ab31c32eae2dffab7c Mon Sep 17 00:00:00 2001 From: Thomas Lamprecht Date: Wed, 11 Nov 2020 10:06:36 +0100 Subject: [PATCH] docs: fix prune retention example Signed-off-by: Thomas Lamprecht --- docs/maintenance.rst | 37 +++++++++++++++++++++++++++++++++++-- 1 file changed, 35 insertions(+), 2 deletions(-) diff --git a/docs/maintenance.rst b/docs/maintenance.rst index 8fadd19f..561b4fe4 100644 --- a/docs/maintenance.rst +++ b/docs/maintenance.rst @@ -76,8 +76,41 @@ edit the interval at which pruning takes place. :align: right :alt: Prune and garbage collection options -Prune Keep Example -^^^^^^^^^^^^^^^^^^ + +Retention Settings Example +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The backup frequency and retention of old backups may depend on how often data +changes, and how important an older state may be, in a specific work load. +When backups act as a company's document archive, there may also be legal +requirements for how long backup snapshots must be kept. + +For this example, we assume that you are doing daily backups, have a retention +period of 10 years, and the period between backups stored gradually grows. + +- **keep-last:** ``3`` - even if only daily backups, an admin may want to create + an extra one just before or after a big upgrade. Setting keep-last ensures + this. + +- **keep-hourly:** not set - for daily backups this is not relevant. You cover + extra manual backups already, with keep-last. + +- **keep-daily:** ``13`` - together with keep-last, which covers at least one + day, this ensures that you have at least two weeks of backups. + +- **keep-weekly:** ``8`` - ensures that you have at least two full months of + weekly backups. + +- **keep-monthly:** ``11`` - together with the previous keep settings, this + ensures that you have at least a year of monthly backups. + +- **keep-yearly:** ``9`` - this is for the long term archive. As you covered the + current year with the previous options, you would set this to nine for the + remaining ones, giving you a total of at least 10 years of coverage. + +We recommend that you use a higher retention period than is minimally required +by your environment; you can always reduce it if you find it is unnecessarily +high, but you cannot recreate backup snapshots from the past. .. _maintenance_gc: