How to use and request AFS playpen space
Reviewed by John Sopko 6/17/2014
Please read the following notes on how to use the public UNC Comp Sci AFS playpen space before you start inserting data there. If you are not familiar with the AFS filesystem please see the AFS introduction.
In general, anything on UNIX systems located in a playen directory is NOT backed up to tape. There is a 24 hour online snapshot of all files in AFS playpen space; if you delete files and they were there during the last online backup you can restore the files as described below. The afs snapshot takes place at 2am and usually finishes by 2:20am.
To use the AFS playpen space, you first need to email email@example.com and request that a directory be set up for you under /afs/cs.unc.edu/playpen. An AFS volume will be created for you and a directory mount point will be placed in /afs/unc/playpen/loginwhere “login” is your login name. For example, /afs/cs.unc.edu/playpen/aardvark would be the playpen space for user aardvark.
You will be given full AFS permissions on your directory, which will have an initail 8 GB quota. If you need more you can request an additional 8GB added to your quota. Computer services will periodically contact users to clean up space if the space gets filled up, but please keep track of your own space and clear out data you don’t need. There are currently 260 GB available in playpen space, and a lot of folks use this space. Also, note that /afs/unc is a link to /afs/cs.unc.edu, so you can access the above playpen directory as /afs/unc/playpen/aardvark.
You can make a Linux softlink in your AFS home directory to your AFS playpen space if you wish. For example to make a linkecalled “playpen” in your home directory to link to your AFS playpen space:
cd (change to your home directory)
ln -s /afs/cs.unc.edu/playpen/login playpen
So accessing /afs/cs.unc.edu/home/login/playpen will land in your AFS playpen space. If you want to make space that is accessible under your home web page:
ln -s /afs/cs.unc.edu/playpen/login/files files
This will make a link from your public_login/files to your AFS playpen login/files directory. You can access this space via the web server https://cs.unc.edu/wp-login.php
How to get back a file you deleted
A snapshot of the directories/volumes located in /afs/cs.unc.edu/playpen is taken nightly starting at 2:00 am. If your files were present at that time, they will be available as read only files until the next 2am snapshot is taken. That is, a copy of your read/write files is placed in the read only backup volume at the time of each snapshot. The read only copy of these files is located at: /afs/unc/playpen/last_backup/login. Simply go to the directory where your files are located and copy them to the read/write directory. Remember, a snapshot is taken every night and your files will be lost if you do not get them back before the next snapshot. For instance, say you create a file Monday morning and work on it all day. Tuesday at 2:00am a backup volume is created that contains all the data at the time of the backup. You then accidently delete the file Tuesday at 3:00pm. Simply go to the last_backup/* location to get a copy of your file.