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Full Discussion: Slow Copy(CP) performance
Special Forums Hardware Filesystems, Disks and Memory Slow Copy(CP) performance Post 302360369 by jim mcnamara on Thursday 8th of October 2009 05:29:58 PM
Old 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 HPUX

rmf

RMF(1)                                                               [nmh-1.5]                                                              RMF(1)

NAME

       rmf - remove an nmh folder

SYNOPSIS

       rmf [+folder] [-interactive | -nointeractive] [-version] [-help]

DESCRIPTION

       Rmf removes all of the messages (files) within the specified (or default) folder, and then removes the folder (directory) itself.

       If  there  are  any  files  within the folder which are not a part of nmh, they will not be removed, and an error will be produced.  If the
       folder is given explicitly or the -nointeractive option is given, then the folder will be removed  without  confirmation.   Otherwise,  the
       user  will be asked for confirmation.  If rmf can't find the current folder, for some reason, the folder to be removed defaults to `+inbox'
       (unless overridden by user's profile entry "Inbox") with confirmation.

       If the folder being removed is a subfolder, the parent folder will become the new current folder, and rmf will produce  a  message  telling
       the user this has happened.  This provides an easy mechanism for selecting a set of messages, operating on the list, then removing the list
       and returning to the current folder from which the list was extracted.

       If rmf s used on a read-only folder, it will delete all the (private) sequences (i.e., "atr-seq-folder" entries) for this folder from  your
       context without affecting the folder itself.

       Rmf irreversibly deletes messages that don't have other links, so use it with caution.

FILES

       $HOME/.mh_profile          The user profile

PROFILE COMPONENTS

       Path:                To determine the user's nmh directory
       Current-Folder:      To find the default current folder
       Inbox:               To find the default inbox

SEE ALSO

       rmm(1)

DEFAULTS

       `+folder' defaults to the current folder, usually with confirmation
       `-interactive' if +folder' not given, `-nointeractive' otherwise

CONTEXT

       Rmf  will  set the current folder to the parent folder if a subfolder is removed; or if the current folder is removed, it will make "inbox"
       current.  Otherwise, it doesn't change the current folder or message.

BUGS

       Although intuitively one would suspect that rmf works recursively, it does not.  Hence if you have a sub-folder within a folder,  in  order
       to rmf the parent, you must first rmf each of the children.

MH.6.8                                                             11 June 2012                                                             RMF(1)
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