10-08-2009
Rule of thumb:
Seriously consider never letting a given filesystem get above 80-85% full.
Filesystems under heavy I/O loads suffer from various kinds of latency issues
when free space becomes tight, file allocation times increase as well.
The other caveat:
Assuming loads of available free inodes, huge directory files (the directory file itself, not what is in the directory) are the result of adding lots of files to a single directory. As the directory file itself grows, system performance against it - ls, find, stat, etc. - becomes very poor.
This is because any operation that does a readdir, which is sequential, is really slow if it has to read thru 2 million entries to find one filename.
When files are deleted from the bloated directory, it does not shrink. You have to park the remaining files somewhere, delete the directory, recreate the directory, then move the files back into it. And you have a new, smaller size directory file. Having broader directory trees solves this problem in the first place.
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LEARN ABOUT OSF1
rmtrashcan
mktrashcan(1) General Commands Manual mktrashcan(1)
NAME
mktrashcan, rmtrashcan, shtrashcan - Attaches, detaches, or shows a trashcan directory
SYNOPSIS
/usr/sbin/mktrashcan trashcan directory...
/usr/sbin/rmtrashcan directory...
/usr/sbin/shtrashcan directory...
OPERANDS
Specifies the directory that contains files that were deleted from attached directories. Whenever you delete a file in the specified
directory, the file system automatically moves the file to the trashcan directory. Specifies the directory that you attach to a trashcan
directory.
DESCRIPTION
The trashcan utilities (mktrashcan and rmtrashcan) enable you to attach or detach an existing directory, which you specify as a trashcan
directory, to any number of directories within the same fileset.
A trashcan directory stores the files that are deleted with the unlink system call. For instance, you can use the mktrashcan utility to
attach a trashcan directory called /usr/trashcan to one or more directories; thereafter, when you delete a file from one of the attached
directories, the file system moves the file to the /usr/trashcan directory. Note that when more than one directory shares attachment to a
trashcan directory, files with the same file name can overwrite each other in the trashcan directory.
If you mistakenly delete a file, use the mv command to return the file from the /usr/trashcan directory to its original directory.
When you enter shtrashcan at the system prompt, the system shows the trashcan directory, if one exists, for the directory you specified.
It is important that trashcan directories have correct access permissions. If the permissions are too restrictive, then it may be impossi-
ble to remove files from the directories that are attached to the trashcan directory. In general, all users and groups that expect to use
the trashcan directory need write permission to the directory. If unexpected "permission denied" errors occur when deleting files that are
in a directory attached to a trashcan directory, use the chmod command to change the permissions on the trashcan directory.
RESTRICTIONS
The directory and trashcan directories must be in the same fileset; however, you can attach the trashcan directory to any directory within
the fileset.
EXAMPLES
The following example creates and attaches a trashcan directory, /usr/trashcan, to two directories, /usr/ray and /usr/projects/sql/test,
which are in the same fileset. The chmod command adds write permission for all users and groups on the new trashcan directory. % mkdir
/usr/trashcan % chmod a+w /usr/trashcan % mktrashcan /usr/trashcan /usr/ray /usr/projects/sql/test To attach the trashcan directory,
/usr/trashcan, to all subdirectories in the /usr directory, enter: % mktrashcan /usr/trashcan /usr/*
New subdirectories that you add beneath the /usr directory are not attached to the trashcan directory until you attach them. Also,
the mktrashcan utility distinguishes between directories and files, attaching only directories to the trashcan directory.
Note that an attached directory produces an EDUPLICATE_DIRS (-1165) error when /usr/trashcan is itself in the directory path you
attach to (as in the previous example). You can ignore this error message.
SEE ALSO
advfs(4), mkfset(8), showfsets(8)
mktrashcan(1)