JFS2 over JFS 1

[costiles]

What are the advantages - disadvantages?

 

[p5wizard]

JFS2 is newer, did have a few teething troubles at first, should be stable by now.

JFS is ok for small filesystems. JFS2 has lower overhead and is inherently better suited for big files (you would need to specially create a JFS with non-default allocation parameters in order to host big files).

JFS2 works better in a 64-bit AIX kernel than a 32-bit AIX kernel. JFS works ok in both size kernels.

One BIG advantage of JFS2 = (in AIX53 only I believe) you can grow/shrink a filesystem online (while it is mounted). JFS will only allow you to grow a FS while mounted. And you'd need a third party tool to shrink a JFS and then you'd still need to take the FS offline (unmount) AFAIK.

There's loads more info on JFS and JFS2 online. Google and learn.


HTH,

p5wizard

 

[khalidaaa]

I advice you to read the best document i've ever read on JFS vs JFS2

http://www-03.ibm.com/servers/aix/whitepapers/pseries_aix_perf.pdf

Regards,
Khalid

 

[costiles]

Thank you both for your input. I did read the white paper - and yes - it is the best doc I have read as well!

 

[khalidaaa]

Where is the credit for a valuable post

 

[sbix]

With JFS2 there are some interesting add on like the "concurrente I/O" mount option, which is an enhancement of "Direct I/O"
Concurrent I/O could be useful in junction with Oracle and datafiles onto filesystems