Slow Copy(CP) performance Post: 302359552

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Special Forums Hardware Filesystems, Disks and Memory Slow Copy(CP) performance Post 302359552 by zxmaus on Wednesday 7th of October 2009 12:56:18 AM

10-07-2009

Moderator

Since you don't tell us anything about your OS, your disklayout or anything else, we obviously have to guess, but in any case a copy from A to B that is slow is rather an IO issue than a cpu problem.
My best guess is, that both filesystems are maybe on the same disk and have maybe even different blocksizes. Since your filesystem was almost full, your fragmentation is very likely very high, since the OS had to put additional data where space were left, so typically the data was spread across the remaining diskspace and not nicely lined up like it would have been the case with lots of free space in the volumegroup. And I assume you haven't done a defragfs after cleaning up your diskspace.
When you now copy data from A to B and both locations are on the same disk, your system will take a lot more time to 1. find the data in the 'correct' order in filesystem A and read it - because its spread across the physical volume and 2. it will take a lot of time put the data back to disk in filesystem 'B' in the correct and suitable order - since the system has to find again free blocks big enough for your data chunks - and these chunks are likely as well spread across the entire disk.
Try to defrag your diskspace a few times, maybe that improves performance. If not, backup your data, drop the filesystems, defrag, recreate them and restore the content from backups.

Kind regards
zxmaus

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LEARN ABOUT REDHAT

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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