The ext3 or third extended filesystem is a journaled file system that is commonly used by the Linux kernel and is the default file system in many of the linux kernels. Its main advantage over ext2 is journaling due to which , it is more reliable and the need for checking the file system after an unclean shutdown is eliminated.
Advantages
JFS, ReiserFS and XFS are the other file systems available with linux. its performance (speed) is less attractive than the above. in-place upgrades from the ext2 file system withotu upgrading the data are permitted by this . It is also safer than safer than the other Linux file systems. The advanced features available with ext-3 filesystem are:
- A Journaling file system
- Online file system growth
- Htree indexing for larger directories.
Disadvantages
many of the on-disk structures are similar to those of ext2 as it is reverse compatible with ext2. extents, dynamic allocation of inodes, and block suballocation are nat available in this filesystem.
Defragmentation
no online ext3 defragmentation tool working on the fiesystem level ia available. ext3 is more resistant to file fragmentation by storing the data in free block that is nearest to other blocks in a file. online filesystem defragmentation utility i splanned to be included in ext4 filesystem.
Recovery
deleted file recovery is not provided in the filesystem. file inodes are wiped out during deletion.
Compression
transparent compression is not available , but it has been made available as an as an unofficial patch for ext3.
for full details, visit:
http://en.wikipediawiki/Ext3
http://batleth.sapienti-satprojects/FAQs/ext3-faq.html
ppt:
http://nrg.cs.ucl.ac.uk/mjh/3005/15-file...mples2.pdf