mini-FAQ for Hard Disk Quotas

Beginning February 14th, we're going to start using quotas for disk space for home directories here on allspice. As more and more students get accounts in the CS department, the amount of available free disk space per user decreases, and we just want to make sure that there will always be enough room for everyone to be able to compile their programs, turn in their homework, read their mail, and all the other various uses that one would normally expect.

So we sysadmins would be more than happy to answer any questions that you might have about quotas and what's going on, and we've even taken the time to answer a few of what will probably be the most frequently asked questions ahead of time! So if you're wondering something, read on, and if you still don't feel your question was answered, feel free to send an email to local-staff@cs.swarthmore.edu!

-------------Answers to your questions about quotas----------------

What's a "mini-FAQ"?

FAQ stands for "Frequently Asked Questions", and are often found on the internet, covering topics ranging from gardening to kernel configuration. They are often much larger and follow a rather bulky format, so this is just a smaller version of one, hence the 'mini'.

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Why do we need quotas?


Even though we have been buying more disk-space to try and accommodate for all the new students in our department, we're simply growing too fast as a department to realistically continue with the previous policy of disk usage. Disk space is a finite resource, and we want to make sure that it's managed fairly and efficiently as we can. Last semester, for example, there were a few occasions where one of the disks on which home directories are stored filled up, much to the chagrin of half the students of the department! So, we'd like to keep that from happening again. :)

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Okay, how much space do I get?


That depends on which courses you're taking. Some courses are much more disk-intensive than others--and it wouldn't be fair to hold everyone to the same standards if they had different needs. So, we've made a system of three tiers, separating the courses by how much disk space they typically require. To find out which quota applies to you, find the course with the highest tier that you've taken, and that's how much space you get!


Tier I 	(30MB) - Non disk-intensive courses
	CS21, 22, 23, 35, 41, 46

Tier II (60MB) - Slightly more disk-intensive courses
	CS43, 44, 45, 63, 75

Tier III (90MB) - The Biggun's
	CS81, 27, 40

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What happens if I use up more space than my quota?


Good question. These quotas are what we call "soft" quotas. That is, there won't be a big horned daemon to crawl out from the server room and devour you if you go over (we're working on that, just a few contract details, eheh...). You'll just get a little message from one of us informing you that you're over quota, and you'll be asked to clean up your directories (See "How can I lower my disk usage?"). We do, however, have a "hard" quota, which if reached will not allow you to write any more until you clear up some space. Also, if you remain above your soft quota for more than a few days, you'll be prevented from writing anymore to disk until you tidy up a bit.

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How do I know how much disk space I'm already using?


Another good question! From the command line, type:

du -sk /home/yourusernamehere

and this will tell you how many kilobytes of space you're currently using. Divide that number by 1024 (1024 kb = 1 mb), and bingo, that's your current disk usage.

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How can I lower my disk usage?


The first thing we recommend doing is looking for any core files left from a crashed program. Often, these files can be 5-10 MB just by themselves! Other things you can do to preserve space include tarring and bzipping directories and files that you're not currently using, deleting any object files (*.o or *.a) and any extra backup files that editors like emacs and jove like to leave around (ones that end in '~' or start with '#'). Also, if you're starting to fill up on space, you should consider removing any files that aren't cs related, as you most certainly have your own cpu (or an sccs account or your student folder) for that kind of stuff.

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But I HAVE to do this project and it takes up more than my quota!


Fear not. If you need temporary storage space, temporary storage space you can get! Just ssh over to any of the clients and cd into /local. You can plop whatever it is that you need to plop in there. However, we *strongly* emphasize the word "temporary" for this space, as we do not back it up and will without hesitation delete stuff cluttering it up if it starts to fill.

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My question still isn't answered!


Send us an email (local-staff@cs.swarthmore.edu)!

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