xxxxxxxxxxxxxxxxxxxxx Diff ext2 ext3 ext4 xxxxxxxxxxxxxxxxxxxxxxxxxExtended n file system
- Introduced with kernel 1.0 in 1993
- Flexible can handle upto 4TB
- Support file-name upto 1012 chars
- super block feature increase file system performance
- ext2 reserve 5% of disk space for root
- ext2 is popular on USB and other solid-state devices.
This is because it does not have a journaling function.
so it generally makes fewer reads and writes to the drive,
effectively extending the life of the device .
- NO journalalizm
- Provide all the feature of ext 2 + journaling and backward compatibility .
- can upgrade ext2 to ext3 without loss of data.
- journaling feature speed up the system to recover the state after power-failure
or improper mount unmount etc.
- Example: In ext2 in an improper unmount or in-between power-off etc.. so in time
of receiver it checks whole file system .
But in ext3 it keeps record of uncommitted file transactions and checks applied
on on them so system will come back up in faster and quicker .
- Introduced with kernel 2.6.28
- Ext4 is a deeper improvement over Ext3
- support larger filesystem, faster checking, nanosecond timestamps,
and verification of the journal through checksums.
- It’s backward and forward compatible with versions 2 and 3, so we can
mount a ext2 or ext3 filesystem as ext4 .
- The main benefits that ext4 has over ext3 are:
- faster time-stamping
- faster file system checking
- journaling check-sums
- extents (basically automatic space allocation to avoid fragmentation)
What is Journalism in linxu file syatem ?
A journaling file system is a file system that keeps track of the changes that will be made in
a journal (usually a circular log in a dedicated area of the file system) before committing them to
the main file system. In the event of a system crash or power failure, such file systems are quicker
to bring back online and less likely to become corrupted.