Staying within Your Disk Quota

• Introduction
• Deleting files
• Archiving files
  • to removable media
  • to disk
  • to the Hierarchical Storage Manager
• Compressing files
• Leasing disk space

Introduction

Disk space quotas provide a means of monitoring a vital computing resource. There are limits on the amount of storage space. ITC's systems have quotas which are enforced. The amount of disk space depends on your affiliation with the University when the account was created. Information on quotas, how much space you have, monitoring your disk quota, reaching the limits of your quota and getting more space can be found in the following document:

http://www.itc.virginia.edu/desktop/homedir/quotas.html

Deleting files

Deleting files is certainly the easiest way to reduce your disk usage. A long listing of files can be viewed with the Unix command ls -l, and used to identify the largest, unneeded, and possibly obsolete files from this list. For example, the following list contains all three categories:

31480 -rw-r--r--   1 mst3k    usr    32232736 Oct 14 1999  1910cens.dta
   4 drwxr-xr-x   4 mst3k    usr        512 Nov  6 18:42 Mail/
   4 drwxr-xr-x   9 mst3k    usr        512 Jan 20 2000  OldFiles/
   4 drwxr-xr-x   3 mst3k    usr        512 Jan 20 2000  Umenu/
5100 -rw-r--r--   1 mst3k    usr    5218978 Dec  1 2000  alpha1.TIF
5096 -rw-r--r--   1 mst3k    usr    5218072 Nov 13 2000  alpha5.TIF
  16 -rw-r--r--   1 mst3k    usr      15671 Aug 10 1999  compare
   4 -rw-------   1 mst3k    usr  
   4 drwxr-xr-x   2 mst3k    usr       1536 Jul  7 10:23 bin/
   4 -rw-------   1 mst3k    usr        768 Aug 15 12:31 dead.letter
   4 -rw-r--r--   1 mst3k    usr        349 Aug 12 1997  distfile
   4 -rw-r--r--   1 mst3k    usr        421 Dec 29 1997  distfile.tin
   4 -rw-r--r--   1 mst3k    usr        196 Aug 18 1998  distfile1
   4 -rw-r--r--   1 mst3k    usr         84 Mar 28 1996  firms
   4 -rw-------   1 mst3k    usr        361 Jun 16 1995  form.out
   4 -rwxr-xr-x   1 mst3k    usr       1137 Sep 19 1997  forward.hy*
 356 -rw-r--r--   1 mst3k    usr     362111 Jun  6 1995  fund.gz
6292 -rwxr-xr-x   1 mst3k    usr    6446099 Oct 21 1998  pine.4.05* 

Archiving files

• To Removable Media
  Possible media are floppy disks, Zip disks, tape cartridges, and writable CD's. Their major advantage is that they are portable. The choice depends on the size of the data, whether the data must be easy to retrieve, how permanent the copy needs to be, and how portable it must be.
  The census data is very important and you will read it often, but it is not data that you write to. It does not hold data that needs to be quickly available. A writable CD would be ideal. The tradeoff is that you must have access to a CD burner.
  The two .TIF files are images that are works-in-progress and need to be readily available on a medium that can easily be rewritten and is portable. If a Zip drive is available, these could be stored, read, revised, rewritten, and carried from site to site ad infinitum.
  The files from 1995 and the copy of pine could be written to a tape cartridge and stored in the Machine Room. Additional information on making tape cartridges and requesting them for use is given in the following document:

http://www.itc.virginia.edu/desktop/unix/oldtapes.html

• To Disk
  What if you do not have access to the removable media mentioned above? Some space reduction is possible if you archive a large file or disk directory to a disk file, then remove the original directory. On the UNIX system you can use the tape archive command tar to create the archives on the disk instead of on tape. Tar commands with options that perform the more common functions are given below. The v flag asks for verbose display of names of files added to the archive, and the f flag names the archive with the characters immediately following. It may be advantageous to have the complete directory archived into a single file.

  Command Format	Effect of Command
  tar -cvf bigdir.tar bigdir	archive directory bigdir into file bigdir.tar
  tar -tvf bigdir.tar	list table of contents of archive file bigdir.tar
  tar -xvf bigdir.tar bigdir	extract (into original format) contents of bigdir.tar
  tar -xvf bigdir.tar bigdir/file1	extract file named file1 within directory bigdir

  
  
  

• To the Hierarchical Storage Manager
  Large directories or data files can be archived to the mass store archive and then removed from the home account disk. The Hierarchical Storage Management (HSM) system consists of a tape robot and Data Storage Manager. It is an archive system that uses magnetic tape to store data on and should not be used to store files that are regularly used or are small in size (generally less than 50KB). The HSM is dedicated to providing users with a place to store large, infrequently used data files. Details about temporary and permanent file storage options, from /tmp, /bigtmp, and /longtmp to writable CDs, are outlined in the document Data Access and Archiving Overview. A thorough treatment of the HSM is available at

http://www.itc.virginia.edu/research/hsm.html

Compressing Files

Files can be reduced in size using one of the compresssion utilities. PC and Macintosh users at the University may get the WinZip and ZipIt programs, respectively, from ITC Software Central. Unix users may use the gzip, compress, and pack commands.

Leasing Disk Space

Additional space is available in "wedges" of disk that can be leased in increments of 250 MB by individuals and/or by departments. Please see the following document for specific information:

http://www.itc.virginia.edu/unixsys/storage.html