Difference Between JFS and JFS2 in AIX

In this post you will know differences between JFS(Journal FileSystem) and JFS2 (Enhanced Journal FileSystem) . Before going to create JFS or Enhanced JFS filesystem you want to create JFS or Enhanced JFS logical volumn.TO avoid the JFS/JFS2 logical volumn creation seperatly you can create JFS or Enhanced JFS filesystem on the top of volumn group(rootvg,datavg) it automatically create JFS/JFS2 logical volumn and LOG logical volumn. Advantage of of JFS/JFS2 log LV is, it track and store the information of JFS/JFS2 filesystem. Incase filesystem crashed or corrupted you can recover by using log devices(log LV).

Your volumn group having JFS and Enhanced JFS2 filesystems, two individual LOG LV's were created to store transactions.Here are the differences between JFS and Enhanced JFS.

JFS (Journal File System) :

1.  Kernel size is 32 bit

2.  Maximum file size is 64 gigabytes(GB)

3.  Maximum file system size is 32 terabytes(TB)

4.  Number of I-Nodes are fixed

5.  Need to enable large file

6.  Supports online defragmentation

7.  Supports compression

8.  Only increase the filesystem, it not supported to decrease filesystem

9.  Supports quotas

10. Supports direct I/O operations

JFS2 (Enhanced Journal File System) :

1.  Kernel size is 64 bit

2.  Maximum file size is 4 petabytes(PB), currently it supporting up to 16terabytes(TB)

3.  Maximum file system size is 4 petabytes(PB)

4.  Dynamically increase I-Node size, based on disk space

5.  By default large file

6.  Supports online defragmentation

7.  Not supports compression

8.  Supports increase and decrease the file systems

9.  Supports quotas

10. Supports direct I/O operations

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