|
Table of Contents
General information on WAM and Glue account quotas
The Office of Information Technology (OIT) Workstations at Maryland (WAM) and Glue (including GRACE) systems have a limit on the amount
of disk space, or quota, that you can use for storing files. The current
default quota on WAM and Glue is 100 megabytes (MB). If you come close to
or exceed your allotted quota, it can cause various things to happen.
How a disk quota problem can manifest itself
If you are near or over your disk quota, it can manifest itself in different
ways, depending upon how you access the system. If you only login to the
WAM
lab Windows machines, it might be as obvious as a warning message in a
pop-up window when you log on or off, it can be as subtle as appearing to be
receiving new e-mails, or not being able to delete mail items because your
Inbox is "read only." If you login to the UNIX environment via
a telnet/ssh connection, you may see a
warning message at login time (more on this later).
Some basic space usage concepts
When you login to the Windows or Macintosh workstations in the WAM labs
(or one of the public departmental workstation labs that use the WAM
software image), the files that control the behavior of your environment
are stored on your WAM UNIX account. The more (or bigger) files you store
also take up your space allotment (quota). Additionally, the files required
to save and restore your Windows or Mac desktop (called "profiles")
are also stored on your WAM account. Profiles for Windows workstations are
stored in a directory titled .2kprofile, while your Mac profile is
stored in two directories, Library and Desktop.
When you store Word documents, Excel spreadsheets, PowerPoint presentations,
etc., during your WAM Windows or Mac sessions, these also count against
your WAM disk quota. Additionally, when you browse the Internet with any
of the WAM web browsers, all the pages you visit, including text and images,
are stored in what is called the browser cache for quicker loading if
you return to the page(s). All these documents and files add up over time.
The WAM Windows workstations require that the free disk space is equal to
twice the size of your profile directory (".2kprofile")
while logging off. To successfully read e-mail, you
must have at least as much free space equal to the amount of unread mail
in
the file /mail/userid/userid.
Because most of the troubleshooting and problem resolution can be done in the
UNIX environment, much of this document will refer to that process. You will need
to login to the WAM or Glue system via a
telnet/ssh client to issue the commands listed below.
For the purposes of this document, while your Glue account is not usually
used for file storage due to Windows or Macintosh usage in public labs, the
general ideas of disk space usage, discovery, and cleanup are the same as on
the WAM system.
Determining How Much Disk Quota is Being Used and Where Space Is
Being Used
If you login to the WAM or Glue system via
a telnet/ssh client and you are within 85% of
your disk quota, you will see a warning when you login:
Warning: Disk usage at 95%; quota=100000K, used=95008K.
The most likely reasons are a buildup of browser cache files (from WAM Windows
and/or Mac workstations) or mail build up in your Inbox or other folders
(Sent, Trash, etc.).
First, make sure you know what your quota is by logging onto WAM
(via telnet/ssh); and at the system prompt
type:
quota
The quota command will show how much of the 100 megabytes
(MB) quota is being used. The output will show a numeric tally and a
percentage:
rac2> quota
Volume Name Quota Used %Used Partition
user.USERID 100000 95008 95%
The quota tool shows space in kilobytes (KB). For example,
the 100 MB quota will be shown as 100000 (KB).
Finding and Removing Browser Cache Files
In many cases, when file space is used up by Firefox or Internet
Explorer browser cache files, the locally-stored text and images of recently
visited pages can take up several megabytes of disk space. These files
are often the culprit in over- (or near-) quota situations. You have two
options on clearing these leftover cache files, you can manually
delete them while in the browser (which must be done for each browser you
use) or issue a command in the UNIX environment to delete them.
The WAM and Glue systems have a script to remove leftover browser cache files:
clearcache
This will remove the cached files and clear up some space. The
command will issue the quota command before and after attempting
to clear cache files; therefore, you can see how much space (if any) was reclaimed.
It will also list the directories in which it found browser cache files to
delete.
By modifying the preferences of the browser and setting the size limit for the browser cache to zero, you can limit the amount of disk space
taken up by browser cache files. Be aware that the lower you set
the cache size, the fewer files can be stored locally. This means that
more pages, images, etc. will have to be loaded from the remote host rather than
from your local cache, so the rendering of some web pages will be slower.
Unread E-mail
If you are not over quota but still cannot read e-mail normally, you may
have more unread e-mail than available space. If the amount of space being
used is high or there is more unread e-mail than available account quota, the
account may lock and/or refuse to show new mail. In the example above,
the account is currently using 95 MB of space of the total 100 MB maximum quota allowed.
To check whether e-mail is the source of the problem, determine how
much free space you have: subtract the amount of used space from the total
quota (from the quota command), and then compare that to the size
of your unread e-mail (in /mail/USERID/USERID). For example:
ls -l /mail/USERID/USERID
-rw------- 1 70004 users 6210458 Jul 14 9:23 /mail/USERID/USERID
The fifth column of output from the ls command is the size of
the unread e-mail (in bytes or characters). In this example,
there are 6,210,458 bytes or 6.2 MB of unread e-mail. Using the above
example quota, there is
currently only 5 MB of available space on the account; therefore, there is
not enough disk space to
read the e-mail. There is a command you can issue to move the unread e-mail
into your Inbox without using your personal disk space, after which, you should
be able to use your usual e-mail program normally. Type:
catmail
This will append your unread e-mail to your Inbox without utilizing your
own account space.
Deleting E-mail to Free Space
If you are over quota and need to delete one or more e-mail items in order to return to being
under quota, you can use the basic mail (mailx) program. There are
basic instructions on how to do this in the
Using UNIX Mail section of the
Getting Started With Your WAM, Glue, or GRACE
UNIX Account document. For more comprehensive information on the
mail command, refer to the Using
the UNIX Mail Program document.
Type the command:
Mail -f /mail/USERID/USERID
or:
Mail -f /mail/USERID/mbox
Files Removed Did Not Give Enough Space
If clearing your browser cache and reducing your e-mail volume does not
reclaim enough space, you will need to do a little sleuthing to determine
where the space is being used. First, change directory ('cd') to the top
level directory of your account (which is NOT your home
directory):
rac2> cd /users/USERID
The disk usage (du) command shows the size of each file
or directory in the current directory:
rac2> du -sk * | sort -n
The "s" option returns a summary of a directory's
contents (rather than a full listing), and the "k" option
shows the output in 1 KB increments (rather than the default 512 byte
increments). The sort command lists them in ascending size order,
with the largest directory last.
This will show which directory is using your space, "home," "pub," or
"mail." (Ignore the "backup" directory; that is for the nightly backup snapshot
and does not impact your disk usage.)
rac2> du -sk * | sort -n
6234 mail
6018 pub
82819 home
95045 backup
In this example, the home directory is where most of the space is being used:
almost 83 MB.
Directories and Files
Once you have determined which directory is using the most space, change into
that directory and run the 'du' command again, in a recursive
manner, until you determine where the space is being utilized:
rac2> cd directory
rac2> du -sk * .??* | sort -n | tail
This will list all of your files (including "dot files" like
".login", ".cshrc", etc.), again in increasing size order,
the largest being the last listed. In the example above, the output of the
du command is first sorted, then piped through the
tail filter to show only the last (largest) ten files/directories.
You can then examine this list to determine where the space is being used and
decide how to deal with different files. File sizes are listed in kilobytes
(1000 character chunks), so a file with a number of "1000" would be 1000
kilobytes, or one megabyte in size:
rac2> du -sk * .??* | sort -n | tail
1059 Trash
1126 .matlab
1353 mozilla.test.dirs.gz
1782 fy06.doc
2410 jh-doc.mail
3433 ns_imap
5213 .mozilla
8734 Library
52373 .2kprofile
Some directories you may see are ".mozilla" (/Firefox
configurations and working directory), ".2kprofile" (WAM Windows 2000
configurations and working directory) and "Library" (WAM Macintosh
configurations and working directory). In this example, the
".2kprofile" directory is taking up 52.3 MB, so that is the best
place to look for unwanted space usage. Change (cd) into this
directory and run the du command again, repeating the
process until you find the largest file(s) and/or directory(ies).
Dealing with files that are taking space
Once you determine where space is being used, you will then need to decide what
to do to free some space. Your main choices are to delete the file(s),
move them off the account to alternate storage, or compress the contents
to take less space.
To delete (remove) a file you no longer need, use the 'rm'
command:
rac2> rm filename
You can use a Secure File Transfer
Program (sftp, scp) to copy the file elsewhere once you are sure you
have a good copy on the remote host and then remove the local copy.
You can also burn the large file(s) to a CD on the Workstation at Maryland (WAM) Personal Computers (PCs) and Macintosh (Macs). Once
you verify that you can retrieve the file from the CD, you can then delete it
from your WAM account.
You can use the GNU file compression utility 'gzip' to pack
the file into a smaller space:
rac2> gzip filename
This will create filename.gz that can be up to 1/10th the size
of the original. You can also examine the contents of this file with the
'zcat' command, as long as it is a text (not binary) file:
zcat filename
You can uncompress the file back to its original state by typing:
rac2> gunzip filename
Hopefully, the above steps will clear enough disk space to get things working
smoothly again.
For assistance, please contact the OIT
Help Desk.
|
