Places that you can put stuff
There are 4 different kinds of places where you can store your stuff:
- Your Home Directory (a.k.a ~) is where you land when you login. The path to this location is
- /data/commons/username (a.k.a. commons) is where you might place archive material. For most purposes, behaves just like your home directory, but is not at the moment subject to quota.
- /90days/userid (a.k.a ~/90days) is for stuff that's easily reproduced.
- /data/some-project is specially allocated space for special projects.
Home directories are for storing high value difficult to reproduce files that will be of interest to your biographer.
Stuff in your home directory is backed up frequently (See Backups for details). Your home directory includes several special subdirectories such as ~/Desktop -- which holds the files that are shown on your desktop; ~/Documents which is where many applications write by default; ~/Downloads which is where all sorts of useless stuff that you download from the internet winds up -- unless you take action.
/90days/username is a huge partition that is not backed up.
It's good for stuff that is easy to reproduce. As the name implies, things that are not used, disappear from /90days after not being read or changed in 365 days. You'll get a series of annoying warnings before anything is actually deleted so you're not really playing without net. This is great place for intermediate datasets and downloads that you really don't need to keep. The more you can use /90days, the better for the Universe. Consider configuring your browser to download to ~/90days.
Note that ~/90days is a symbolic link to /90days/username the ~ is important. You never want to hurl stuff into plain old /90days you always want to put your stuff in /90days/username (or equivalently ~/90days).
Specially allocated space.
If you working on a project that will take a long time to finish and involves world famous collaborators, we will be happy to allocate a special location for your files.
The Quota Police
Home Directories have impersonally enforced quotas or limits on how much stuff you can put there. Presently the quota is 25GB but you should start to get email from the Demogrpahy Quota Police when you hit about 20GB. The messages are full great information on what to do -- but the main thing is to do something. When you hit 25GB, very unusual but generally unpleasant things start to happen. Unpleasant things are much more unpleasant when (1) they happen during finals week and (2) you know you could have prevented them by being more virtuous. NOTE that it is regrettably possible to suddenly exceed one's quota by unexpectedly writing several gigabyts of giberish. In that situation you might not get a warning before bad stuff happens. Sorry.
As noted above, you will also get email regarding files that have been laying around in in /90days untouched for 360 days. Five days later these files will be gently and respectfully deleted. The warning emails include some very simple steps you can take to restart the 365 day clock. So again -- don't be afraid to use ~/90days. You'll feel better about yourself if you do.
Don't bother to compress files
In the old days, it was useful to compress files using tools like zip or gzip. Now days, the filesystem compress and uncompress automatically because CPUs are faster than disk drives. That means that reads and writes are acutally faster this way AND the files take up less space.
Finding and deleting useless stuff
Cromagnon file managment : throwing the bones to the back of the cave until the cave fills up; then getting a new cave. Was once an efficient way of running one's scientific life, because storage space is cheap relative to the effort involved in getting your bad self to do something. That argument is harder to make as the speed at which the bone cave fills rises and the quality of the stuff in it falls. At some point you spend a lot of time making sure that this isn't the most recent version of the file you're looking for. Just like your mom -- I'm arguing for tidiness.
If your mom and I were both unsuccessful, a good tool for finding files and directories that have outlived their usefulness is findtrash. Just cd to the top of a directory that you want to inspect and type findtrash to see a list of very old and very large files.
Heads UP: moving stuff to Trash does not change your quota situation until you empty the trash.