NBI and Frag Size when creating a JFS 1

[tnelson1]

When creating a filesystem, what are the affects of increasing/decreasing "Fragment Size" and "Number of bytes per inode"? Also, how is the ceiling calculated? I know that if you have a frag size of 4096 and a nbi of 4096, the maximum size (in 512 byte blocks) is 134,217,728. If I increase NBI to 8K or 16K, what will my new FS max size be, and how is it calculated, etc.???

Thanks,
Tim

 

[AIXSPadmin]

nbpi Fragment size in bytes Maximum size in 512-byte blocks
512 512, 1024, 2048, 4096 16777216
1024 512, 1024, 2048, 4096 33554432
2048 512, 1024, 2048, 4096 67108864
4096 512, 1024, 2048, 4096 134217728
8192 512, 1024, 2048, 4096 268435456
16384 512 268435456
16384 1024, 2048, 4096 536870912
32768 512 268435456
32768 1024 536870912
32768 2048, 4096 1073741824
65536,131072 512 268435456
65536,131072 1024 536870912
65536,131072 2048 1073741824
65536,131072 4096 2147483648
AIX Version 4.1 is limited to NBPI values from 512 to 16384.
In AIX Version 4.3, you can have NBPI values from 512 to 128K, with corresponding maximum file system sizes.

 

[tnelson1]

AIXSPadmin,
Thanks for the reply. After doing a little research on my own, I was able to find the list you gave me in the "chfs" man page.

Thanks,
Tim