AIX 4.1.4, 4.1.4.1, & 4.1.5: File size Limits

TECHINFO-0021110

TOPIC

I'm interested in moving a database application from an RS-6000 to a Apple Network Server 700. One of my database files, however, is approaching (and will soon exceed) 2 GB in size.

My application support provider informs me that I will require AIX 4.2 or greater in order to handle a file of this size. Is this true or will AIX 4.1.4.X do the job? Is there a patch or do I have to wait to for AIX 4.2 release for the Apple Network Server 700?

DISCUSSION

The AIX 4.1.4, 4.1.4.1, and 4.1.5 file system data structure is based on the 32-bit addressing scheme, pointers, data blocks, and so on. Therefore 2 to the 31 power which is about 2 GB, is the maximum file size allowed.

AIX 4.2 will support 64 bit addressing, and at that time the maximum file size will greatly exceed the 2GB limit. In order to support file size over 2 GB, you need to wait for AIX 4.2.

The 'ulimit' command can be used to set or examine the resource limits including the file size. The example below, would set the maximum file size to 4,194,304 blocks (512 Bytes/block) which is 2GB, the limit:

ulimit -f 4194304

If you set ulimit -f to this value, the it will show "unlimited" which is the maximum. The default file size is set to 2,097,151 blocks (1 GB).

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