File size > 2Gig 1

[Tison]

I would like to write files greater than 2 gig in size but cannot (using AIX 4.3).<br>I have set all ulimits to -1 but still cannot make a file greater than 2Gig.<br><br>Any ideas ?

 

[baderoor]

well all i can think of is to increase the block size or bytes per inode but you will have to create a seperate filesystem .you must be carefull ,if your files are too small it slow your machine down because of fragmentation.<br>so what you saying is you want to write files in a&nbsp;&nbsp;specific filesystem &gt; 2gig?if so,you wont be able to because the current filesystem hasnt been structured to take large files.for that as i said you will have to create a new filesystem.what would the average file size of each file be?<br>what we did was we allocated a 30gig fs on our server and this is what we did.this is the path im showing.<br><br>smitty &gt;&gt; ssm&gt;file system &gt;&gt; add/change &gt;&gt; jfs &gt; add a jfs to a previously defined LV &gt;&gt; add a Large File Enabled JFS<br><br>fill in the details and when you come to number of bytes and allocation group size you will have to know how big you want it.in our case we set it to the foll:&nbsp;&nbsp;<br>Number of bytes per inode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;131072<br>Allocation Group Size (MBytes)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;64<br><br>just remember this was set to take 30gb so yours will be smaller go through the options. where you see all the + signs means you can view the settings.<br><br>i hope this helps you if you have any problems just reply.<br><br>

 

[ElgisRamon]

Exactly as baderoor says: You need to have a <i>Large File Enabled file system</i> to have what you want... and think: In a normal fs aix allocate space in 4Kb fragments, but in a LFE fs it allocates in 128Kb chunks...<br><br>I hope it works...

 

[ChristopherD]

Tison,<br><br>Even if you have a large enabled file system you may still have a problem creating a file over 2 gig.&nbsp;&nbsp;We were trying to create a large file ( 10 gig) with a COBOL program and were unable to because the COBOL set for AIX compiler does not allow it.&nbsp;&nbsp;We had to write a C program to handle to i/o from the COBOL program.<br><br>If you are using C, you have to specify large file enablement in the compiler options -<br>cc -co $2.o -D_LARGE_FILES -qlist $2.c<br><br>Good Luck!<br> <p>Christopher Devenny<br><a href=mailto:c_devenny@yahoo.com>c_devenny@yahoo.com</a><br><a href= > </a><br>

 

[shiraz]

hi tison<br>I think you have logout and login from session in which you changed ulimits value..<br>....in order to change to be effective.And use lsfs -q against the filesystem in which you want to create large file to see whether the filesystem is a large-filesize enabled<br>fielsystem or not.If not then you have to create one as indicated by baderoor.<br><br>regds<br>shiraz

 

[stu21]

Tison,

I know this issue was a long time ago, but I have done everything mentioned in the text above and canot create files greater than 1Gb.

How did you get around it?

Was it one of the methods above?

stu21

 

[aixqueen]

You probably don't need another opinion, but here is my opinion...
=====================

Be Careful with Large File Enabled


So what is the scoop on the Large File Enabled... Are there any warnings,
gotchas, problems?

The maximum file size in AIX 4.2 is 64 GB, the default max size is still around
1 Gb. This is great that I can now create files bigger than 2 Gb, but there are
some warnings.

Your application must be able to handle files bigger than 2GB. Many
cannot
Don't do large file enabled file systems if you aren't planning on having
files bigger than 2GB, because the overhead for inodes will be larger.
tar and cpio do not currently support files larger than 2GB. Only
backup/restore programs seem to at this point.
Large File System enabled is NOT compatible with AIX 3.2 systems.
Watch your ulimit. This is defined in /etc/security/limits. This will allow
users to create files above the set limit.
Applications must be recompiled using the &quot;-D_LARGE_FILES flag
and must be compiled on a AIX 4.2.x or higher.
See Info-explorer under &quot;large files&quot; for more information.
Some users report that .....Write performance using Large-Files
enabled filesystems appear to be slower. than regular JFS
filesystems...Read performance was not usually affected.
There does not appear to be a way to change or modify existing File
systems to make them Large File System enabled. You must recreate
them with the -bf=true option or in smit.

How do you set up Large Filesystem Enabled filesystems?

1) Make sure you check your ulimit (in .profile or /etc/security/limits) and set
to unlimited -1

2) Create a new filesystem with Large File System Enabled....either from the
command line with the -a bf=true or through smit.. Smit, System Storage
Mgt, File Systems, Add/change/show/delete a File System, Journal File
System, Add a Journal File System, Add a large File enable Journal File
System.

3) Recompile any applications that can handle Large file with the
-D_LARGE_FILES flag in C or get the patches for your Database to handle
the option.....

General Info Large file:

http://www.rs6000.ibm.com/doc_link/en_US/a_doc_lib/aixbman/admnconc/lg_files_under.htm

Overview of Large file

http://www.rs6000.ibm.com/doc_link/en_US/a_doc_lib/aixprggd/genprogc/lrg_prg_support.htm

Command Not supported in Large File enable

http://www.rs6000.ibm.com/doc_link/en_US/a_doc_lib/cmds/aixcmds6/AppendixA.htm

#-)