======Backup======

User Data on VSC is not backuped.

**Backup is solely the responsibility of each user.**

RAID-5 or RAID-6 is used on NFS and BeeGFS servers and Disk Pools on the GPFS servers to protect against single disk failure.
Up to one (RAID-5) or two (RAID-6) or more (Disk Pool) disks failing concurrently can be sustained.

Other failure modes like disk controller failure or filesystem software faults are very seldom but might lead to loss of data.


======Continous Backup of user Data to remote Machines=====

A continuous backup from VSC has to circumvent the entering of the OTP numbers. If it its possible to keep a ssh session alive for a longer time, it can be used to create a tunnel for connecting to a rsync daemon. **Each time this tunnel has been disconnected (e.g. reboot of your machine or a VSC login node) you have to re-login with a OTP to reestablish the ssh tunnel**

Do the following steps:
  - on the remote machine, download a script an execute it. It will setup the configuration for a rsync daemon: <code>
wget https://wiki.vsc.ac.at/lib/exe/fetch.php?media=doku:rsync:rsyncd_setup_remote.sh -O rsyncd_setup_remote.sh
bash rsyncd_setup_remote.sh
</code>
  - On the local machine, also download a script, it will compile the commands for creating the ssh tunnel and using the rsync:<code>
wget https://wiki.vsc.ac.at/lib/exe/fetch.php?media=doku:rsync:rsyncd_setup_local.sh -O rsyncd_setup_local.sh
bash rsyncd_setup_local.sh
</code>
  - start the rsync daemon with the 'start_rsync' command specified in the 'alias' on the remote machine (**!!! remember on which login node you started the daemon, you have to connect to it later**). The command looks like:<code>
rsync --daemon --config=/home/ ..../ rsyncd.conf
</code>
  - open the ssh tunnel 'tunnel_vsc_rsync' on the local machine this will tunnel map a local port to the remote port of the listening rsync daemon. This example maps the local port 5100 to port 8077 on the login node l32: <code> ssh -L 5100:l32.cm.cluster:8077 <user>@l32.vsc.ac.at </code> **(the login node "l32" conntected to  must be the same as in step 3)**
  - do the 'backup_vsc' on the local machine. This command connects via the local port of the ssh-tunnel from step 4 to the remote rsync daemon: <code>rsync --password-file=/home/.../rsyncd.secrets -av --port 5100 rsync://<user>@localhost/myfiles /tmp/ </code>