Writes to files done first in memory
AIX memory maps files in current use. Any writes to files are done first in memory and,
at a later stage, are written out to disk when the sync system call runs (every minute).
The jfslog
The jfslog for each volume group (such as the rootvg /dev/hd8) is a circular log. A
jfslog is created the size of one physical partition, one per each volume group. The
jfslog ensures file system integrity by writing all metadata information to the jfslog
immediately. It does this in the form of transactions, as illustrated in the diagram. File
system metadata consists of changes to the file system structure itself, such as
changes to the inodes and the free list.