A directory is quite similar to a file and the bigger a file gets the longer it takes the system to read it, which is to be expected. Run a "grep" against a file of 10GB and it will take longer than against a file of 1k size.
Let us consider the case where you issue a command
What happens? Before "grep" can start its work the operating system has to find out which file to open. So it looks in the directory "/path/to/some" and searches there for the inode of "file". A "directory" now is nothing else than a (quite unsorted) list of file names and inode-numbers. The longer this list is the longer it will take the take the OS to search it and find the inode it is interested in.
Usually you won't notice even this difference because the OS uses otherwise unused parts of the memory to buffer such information. This is part of the "file system cache": the system won't read the directory information from disk, but use the copy it has already stored in memory. As memory is much faster than disk this will speed up things considerably. But as the directory gets bigger and bigger and memory is a limited resource at some point the list might not fit in memory any more additionally hurting the speed with which this list is searched.
Bottom line: even if there are no theoretical limits there is some practical limit to directory sizes. This practical limit is pushed as hardware gets faster and memory keeps getting bigger, disks getting faster, etc.., but it still remains.
To split a large directory there is no "standard tool" like there is "split" for files. Just create new directories and use "mv" to move files from one to the other. A command like
will physically move a file only of the directories "/path/to" and "/other/path" are not part of the same filesystem. If they are it is simply a matter of removing the directory information from the one list and putting it into the other. It will take the same time regardless of file size, because the file itself is not touched, just "file metadata" - information about files instead of files themselves.
I hope this clears things up.
bakunin
These 2 Users Gave Thanks to bakunin For This Post:
Hi ,
i'm trying to use "find "command with "-size "option but i encounter 2gb file limitation.
Can you confirm this limitation ?
Is there a simple way to do the same thing ?
My command is :
<clazz01g-notes01>/base/base01 # find /base/base01 -name '*.nsf' -size +5242880000c -exec ls... (2 Replies)
Hi All,
Can anyone please clarify me the following questions:
1. Is there any file size limitation in HP-UX 11i, that I can able to create upto certain size of file (say 2 GB) and not more then that????
2. At max. how many files we can able to keep inside a folder????
3. How many... (2 Replies)
Hi,
Iam using an alias to get the file count from one directory using normal ls command like ls file*|wc -l.If my file increases more than 35,000 ,my alias is not working.It shows that arg list too long.
is that can be limitation of ls or problem in alias?
I would appreciate if anyone can... (2 Replies)
Hi,
I'm having a problem with a while loop syntax that doesn't seem to loop correctly.
TODAY=`date +%d%m%Y`
while read hostname
#for hostname in $(cat $CONFIG)
do
OUTFILE=/tmp/health_check.$hostname.$TODAY
if
then
touch $OUTFILE
func_header
else
rm $OUTFILE
... (2 Replies)
Hi,
I search the way to limit, for a group on a AIX 5.3, one telnet session by user (Simultaneous).
I search a lot in /etc/security but the only way found is with the pam authentication that i not use.
No solution found also in smit menu...
Thanks for your help. (2 Replies)
Hello,
I have a problem running a script created in ksh for Linux (Tested on Debian 5.0, Ubuntu Server 10.04 and RHEL 5.1), it works properly. :b:
I trying to pass it to a AIX 5.3. :wall:
The problem is the character limit of 256 on a command system and SED.
I need to cut the contents of... (8 Replies)
Hello.
I am using AIX 6 and If wish to receive more than 500 files via SFTP, I get some time out errors. Could you please advise where is the limit for number of concurrent transfers setup in AIX Box or what is the limit and can that be changed?
Many Thanks (3 Replies)
Hi all,
does any one know ,if there is any limitation on rm command
limitation referes here as a size .
Ex:when my script try to rum rm command which have size of nearly 20-22 GB ..CPU load gets high ?
if anyone know the relation of CPU load and limitation of rm command . (8 Replies)
whats wrong with this addition?
Whats the maximum number of digits can be handled?
pandeeswaran@ubuntu:~/Downloads$ const=201234454654768979799999
pandeeswaran@ubuntu:~/Downloads$ let new+=const
pandeeswaran@ubuntu:~/Downloads$ echo $new
-2152890657037557890
pandeeswaran@ubuntu:~/Downloads$ (4 Replies)
Hi Guys,
I have fresh new installed VIO 2.2.3.70 on a p710, 3 physical SAS disks, rootvg on hdisk0
and 3 VIO clients through vscsi, AIX7.1tl4 AIX6.1tl9 RHEL6.5ppc, each lpar has its rootvg installed on a LV on datavg (hdisk2) mapped to vhost0,1,2
There is no vg on hdisk1, I use it for my... (1 Reply)
Discussion started by: frenchy59
1 Replies
LEARN ABOUT X11R4
perlos400
PERLOS400(1) Perl Programmers Reference Guide PERLOS400(1)NAME
README.os400 - Perl version 5 on OS/400
DESCRIPTION
This document describes various features of IBM's OS/400 operating system that will affect how Perl version 5 (hereafter just Perl) is com-
piled and/or runs.
By far the easiest way to build Perl for OS/400 is to use the PASE (Portable Application Solutions Environment), for more information see
http://www.iseries.ibm.com/developer/factory/pase/index.html This environment allows one to use AIX APIs while programming, and it provides
a runtime that allows AIX binaries to execute directly on the PowerPC iSeries.
Compiling Perl for OS/400 PASE
The recommended way to build Perl for the OS/400 PASE is to build the Perl 5 source code (release 5.8.1 or later) under AIX.
The trick is to give a special parameter to the Configure shell script when running it on AIX:
sh Configure -DPASE ...
The default installation directory of Perl under PASE is /QOpenSys/perl. This can be modified if needed with Configure parameter -Dpre-
fix=/some/dir.
Starting from OS/400 V5R2 the IBM Visual Age compiler is supported on OS/400 PASE, so it is possible to build Perl natively on OS/400. The
easier way, however, is to compile in AIX, as just described.
If you don't want to install the compiled Perl in AIX into /QOpenSys (for packaging it before copying it to PASE), you can use a Configure
parameter: -Dinstallprefix=/tmp/QOpenSys/perl. This will cause the "make install" to install everything into that directory, while the
installed files still think they are (will be) in /QOpenSys/perl.
If building natively on PASE, please do the build under the /QOpenSys directory, since Perl is happier when built on a case sensitive
filesystem.
Installing Perl in OS/400 PASE
If you are compiling on AIX, simply do a "make install" on the AIX box. Once the install finishes, tar up the /QOpenSys/perl directory.
Transfer the tarball to the OS/400 using FTP with the following commands:
> binary
> site namefmt 1
> put perl.tar /QOpenSys
Once you have it on, simply bring up a PASE shell and extract the tarball.
If you are compiling in PASE, then "make install" is the only thing you will need to do.
The default path for perl binary is /QOpenSys/perl/bin/perl. You'll want to symlink /QOpenSys/usr/bin/perl to this file so you don't have
to modify your path.
Using Perl in OS/400 PASE
Perl in PASE may be used in the same manner as you would use Perl on AIX.
Scripts starting with #!/usr/bin/perl should work if you have /QOpenSys/usr/bin/perl symlinked to your perl binary. This will not work if
you've done a setuid/setgid or have environment variable PASE_EXEC_QOPENSYS="N". If you have V5R1, you'll need to get the latest PTFs to
have this feature. Scripts starting with #!/QOpenSys/perl/bin/perl should always work.
Known Problems
When compiling in PASE, there is no "oslevel" command. Therefore, you may want to create a script called "oslevel" that echoes the level
of AIX that your version of PASE runtime supports. If you're unsure, consult your documentation or use "4.3.3.0".
If you have test cases that fail, check for the existence of spool files. The test case may be trying to use a syscall that is not imple-
mented in PASE. To avoid the SIGILL, try setting the PASE_SYSCALL_NOSIGILL environment variable or have a handler for the SIGILL. If you
can compile programs for PASE, run the config script and edit config.sh when it gives you the option. If you want to remove fchdir(),
which isn't implement in V5R1, simply change the line that says:
d_fchdir='define'
to
d_fchdir='undef'
and then compile Perl. The places where fchdir() is used have alternatives for systems that do not have fchdir() available.
Perl on ILE
There exists a port of Perl to the ILE environment. This port, however, is based quite an old release of Perl, Perl 5.00502 (August 1998).
(As of July 2002 the latest release of Perl is 5.8.0, and even 5.6.1 has been out since April 2001.) If you need to run Perl on ILE,
though, you may need this older port: http://www.cpan.org/ports/#os400 Note that any Perl release later than 5.00502 has not been ported to
ILE.
If you need to use Perl in the ILE environment, you may want to consider using Qp2RunPase() to call the PASE version of Perl.
AUTHORS
Jarkko Hietaniemi <jhi@iki.fi> Bryan Logan <bryanlog@us.ibm.com> David Larson <larson1@us.ibm.com>
perl v5.8.9 2007-11-17 PERLOS400(1)