updated readme

README.md

@@ -1,3 +1,23 @@
 # zfs-snapshot-backup
 
-Automatically backup incremental snapshots to a file server.
+**Automatically create (incremental) backups of zfs snapshots on a file server.**
+
+
+This is currently tailored only to our setup of a FreeNAS in combination with
+our virtual server and storage provided by the Rechenzentrum.
+
+The script will create backups of ZFS snapshots for elab journals. The name of
+the ZFS dataset (from wich the snapshots are created) must start with `elabfs-`
+followed by the elab member name, e.g. `LukasMetzler`
+
+The snapshots should be made with the `periodic snapshot task` provided by the
+FreeNAS system. Snapshots should be kept on the NAS for a couple of days
+(currently one week) to allow transfer errors not to interfere with the backup
+process.
+
+The backup process should be run after a snapshot is taken. Proposed is to take
+a daily snapshot at night (currently between 2am and 3am) and start the backup
+process later via cron (currently set to 4am).
+
+The documentation in our wiki can be found at:
+[https://wiki.cpi.imtek.uni-freiburg.de/CPIvServerDocumentation/ElabOnZfs]()