Configuring fsize for Large File Support

Contents

This document addresses the file size limitations and configuration changes that are necessary for writing, uncompressing or creating a file over 2 gigabytes (GB).

The information in this document applies to AIX versions 4.2.1 through 4.3.3.

To view soft limits, enter:

		ulimit -a

Information similar to the following should be displayed.

		time(seconds)        unlimited
		file(blocks)         2097151
		data(kbytes)         131072
		stack(kbytes)        32768

Two requirements exist for creating a file over 2GB.

1. The file system must be large file enabled.
   1. Enter smit fs.
   2. Select Add/Change/Show/Delete File Systems.
   3. Choose Journaled File Systems.
   4. Select Change/Show Characteristics of a Journaled File System.
   5. Choose the file system that you are using.
   6. Scroll down until you get to Large File Enabled.

   NOTE: If the file system is large file enabled, you may use it as it is. If it is not large file enabled, you cannot use this file system. Choose one of the options below to correct the problem.

   • Use a file system that is large file enabled or create one that is large file enabled.
     Or
   • Back up, remove and recreate large file enabled and then restore from backup the filesystem that you intend to use.

2. The fsize for root and the user must be -1.
   1. Using your favorite editor, open the following file:

      /etc/security/limits
      

   2. Scroll down and view the fsize under defaults.

Commonly the fsize will be 2097151 in 512k bytes, just over 1GB. If you have a file system that is not large file enabled, then the largest recognized fsize value is 4194302 (or 2GB). After 2GB, the fsize is not scalable and must be set to -1, which equals unlimited. -1 actually allows for the creation of a 64GB file.

Once both the above criteria are met, the user or root user should be able to create a file above 2GB in the specified file system.

Enter the following commands to list the creation of 1, 2 and 3 GB files.

1. Create a 1GB file:
   /usr/sbin/lmktemp filename1 10737418424

   Create a second 1GB file:

   cp filename1 filename2

   To create a 2GB file, append the first file to the second file:

   cat filename1 >> filename2

   To create a 3GB file, append the first file to the second file again:

   cat filename1 >> filename2