Migrate backing up Plone docs

docs/backend/upgrading/preparations.md

@@ -4,15 +4,15 @@ myst:
     "description": "Plone upgrade preparations"
     "property=og:description": "Plone upgrade preparations"
     "property=og:title": "Plone upgrade preparations"
-    "keywords": "Plone, upgrade, preparations"
+    "keywords": "Plone, upgrade, preparations, ZODB, collective.recipe.backup, buildout, backup, restore"
 ---
 
 
 (upgrade-preparations-label)=
 
 # Preparations
 
-This chapter lists things to do before you migrate Plone.
+This chapter describes things to do before you migrate Plone.
 
 
 (upgrade-gather-informationlabel)=
@@ -56,18 +56,83 @@ If Plone is being upgraded at the same time as a Zope version, Plone will usuall
 Always back up your Plone site before upgrading.
 ```
 
-```{seealso}
-See Plone 5.2 documentation, [Backing up your Plone deployment](https://5.docs.plone.org/manage/deploying/backup.html).
-```
+This back up guide assumes the following.
 
-```{todo}
-Migrate the Plone 5.2 docs for Backing up your Plone deployment into Plone 6 docs.
-```
+-   You back up your Plone site.
+-   You back up your buildout and its caches.
+-   You back up your persistent data storage using a strategy that maintains data integrity without taking down your Plone site, that is performed periodically with adequate frequency, and that stores sufficient versions of your data.
+-   You've tested the restore process.
+
+
+### Where's my data?
+
+Your Plone instance installation contains a directory {file}`./var`.
+This directory is located in the same directory as the file {file}`buildout.cfg`.
+It holds the frequently changing data files for the instance.
+{file}`./var` contains the instance's log, process ID, and socket files.
+
+The following directories contain your instance's content.
+
+
+#### {file}`./var/filestorage`
+
+The Zope Object Database ({term}`ZODB`) file storage is maintained in the directory {file}`./var/filestorage`.
+The default file name is {file}`Data.fs`, although you could have multiple files or renamed it.
+It's typically a large file which contains everything except {term}`blob`s.
+
+The other files in this directory with the file extensions of `.index`, `.lock`, `.old`, or `.tmp` are ephemeral, and will be recreated by Zope if they're absent.
+
+
+#### {file}`./var/blobstorage`
+
+The directory {file}`./var/blobstorage` contains a deeply nested directory hierarchy that contains the blobs of your database.
+These files may include PDFs, images, videos, office automation files, and other binary objects.
+
+`filestorage` and `blobstorage` are maintained synchronously.
+`filestorage` has references to blobs in `blobstorage`.
+If the two storages are not synchronized, you'll get errors whenever their data is accessed.
+
+
+### `collective.recipe.backup`
+
+[`collective.recipe.backup`](https://pypi.org/project/collective.recipe.backup/) is a well-maintained buildout recipe that maintains data integrity for a live Plone database.
+
+See its `README.md`'s section [Introduction](https://github.com/collective/collective.recipe.backup?tab=readme-ov-file#introduction) for its buildout recipe configuration.
+
+The recipe supports several options, all of which are documented its `README.md`'s section [Supported options](https://github.com/collective/collective.recipe.backup/blob/master/README.rst#supported-options).
+
+Perhaps the most useful option is `location`, which sets the destination for backup files.
+Its default value is `var/backups`, inside the buildout directory.
+The backup destination, may be any attached location, including another partition, drive, or network storage.
+
+
+#### Operation
+
+After running buildout to configure `collective.recipe.backup`, you'll find {file}`bin/backup` and {file}`bin/restore` scripts in your buildout directory.
+Since all options are set via buildout, there are few command-line options, and operation is generally through bare commands.
+
+{file}`bin/restore` will accept a date-time argument, if you keep multiple backups.
+For restore operations, stop Plone before starting your restore, and restart after the restore is complete.
+
+{file}`bin/backup` is commonly included in a cron table for regular operation.
+You can run backup operations without stopping Plone.
+Make sure you test your backup and restore process before you need it.
+
+
+### Incremental backups
+
+`collective.recipe.backup` offers both incremental and full backups, and will maintain multiple versions of backups.
+Tune these to meet your needs.
+
+When you enable incremental backups, the database packing operation will automatically cause the next backup to be a full backup.
+
+If your backup continuity need is critical, then your incremental backup schedule may need to be frequent.
+Some Plone sites require incremental backups every few minutes.
 
 
 (upgrade-setup-a-test-environment-to-rehearse-the-upgrade-label)=
 
-## Setup a test environment to rehearse the upgrade
+## Set up a test environment to rehearse the upgrade
 
 ```{danger}
 Never work directly on your live site until you know that the upgrade was successful.

docs/glossary.md

@@ -919,4 +919,8 @@ TDD
     -   Write the functional code until the test passes.
     -   Refactor both new and old code to make it well structured.
 
+BLOB
+Binary Large Object
+    A blob is a mass of data in binary form that does not necessarily conform to any file format.
+
 ```