Linux ext2/ext3 file system nodes use the index to record documents, like the windows of the File Allocation Table. Index node is a structure that contains the length of a document, create and modify the time, competence, their relations, the position of the disk, and other information. A document indexing system maintenance of a node array, each file or directory index nodes with an array of only one element counterparts. Indexing system to each node allocated a number, which is the node in the array index, known as the nodes of the index. linux file system to document and index nodes, while preserving the file name in the directory. Therefore, the directory will be only the name and its index nodes, combined with a table, each directory on the file name and index nodes known as a link. For a document, there are only the nodes of the corresponding index, an index of nodes, it can have multiple file names corresponding. Therefore, on the disk with a file can be different paths to access it.

Linux use the default file system for Ext2, ext2 file system is highly efficient and stable. However, with Linux systems in the application of business-critical, Linux file system has gradually exposed weaknesses: the use of the system’s default ext2 file system of non-log file system. This key industry in the application is a fatal weakness. In this paper, to introduce the use of Linux ext3 log file system applications.

Ext3 file system directly from the Ext2 file system developed from the current ext3 file system has been very stable and reliable. It is fully compatible with ext2 file system. Users can smooth transition to a log function of a sound system to the paper. This is actually a log file system is ext3 initial design of the original intention.

Ext3 log file system features:

1, high availability

System uses ext3 file system, even in non-normal shutdown, the system does not need to check file system. After the downtime, recovery time ext3 file system as long as tens of seconds.

2, the integrity of the data:

ext3 file system can greatly improve the integrity of file system to avoid accidents on the file system downtime damage. To ensure data integrity, ext3 file system are two kinds of patterns to choose from. One of them is “while maintaining the file system and the consistency of the data” mode. This way, you will never see because of non-normal shutdown and storage on disk of waste paper.

3, the speed of file system:

Although the use of ext3 file system, sometimes in the data storage may have to write data on many occasions, but, generally seems, ext3 than ext2 some even better performance. This is because ext3 journaling on the disk drive read-write head has been optimized. Therefore, the file system to read and write performance than Ext2 file system and, performance, and no lower.

4, data conversion

By the ext2 file system into ext3 file system very easy, as long as the two simply type the command to complete the conversion process, users do not have to spend time backup, recovery, such as formatting Division. With a ext3 file system provided by the gadget tune2fs, it ext2 file system can be easily converted to ext3 log file system. In addition, ext3 file system can not by any changes, and loaded directly into ext2 file system.

5, multi-mode log

Ext3 a number of log model, a model is the work of all the data and document metadata (definition of file system data in the data, data data) log records (data = journal mode) and another one of the working model is Only the metadata record of the log, rather than the data logging, the so-called data = ordered or data = writeback mode. System management system based on the actual work requirements, the system’s speed and work documents the consistency of the data to choose between.

Actual use Ext3 file system

Create a new ext3 file system, for example, to hda8 district on the disk format ext3 file system, and logging in / dev/hda1 district, then operations are as follows:

[root @ stationxx root] # mke2fs-j / dev/hda8
mke2fs 1.24a (02-Sep-2001)
Filesystem label =
OS type: Linux
Block size = 1024 (log = 0)
.. .. ..
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 30 mounts or
180 days, whichever comes first. Use tune2fs-c or-i to override.

In creating a new file system, you can see, ext3 file system automatically detects the implementation of the time for 180 days or every 31 was the first mount, in fact this parameter can freely adjust as needed.

Following the new file system mount to the main district / data directory:

[root @ stionxx root] # mount-t ext3 / dev/hda8 / data

Note: The above will be formatted for the ext3 file system / dev/hda8 district to load / data directory.

ext3 code based on ext2, it ext2 disk format and the same, it means that a clean uninstall the ext3 file system can be re-pegged ext2 file system installed. Ext3 file system still could be loaded into ext2 file system to use, you can put a file system in the ext3 and ext2 free switch.

At this time in the ext2 file system on the ext3 log files still exist, just log ext2 not recognize it.

Ext2 file system will be converted to ext3 file system

Linux system will be the ext2 file system from go to ext3, following several advantages: first enhance system availability, data integration, the second increase, the speed of the start of the third, fourth and ext3 file system ext2 between Conversion easy.

To convert file system as an example, the ext2 file system will be converted to ext3 file system, orders are as follows:

[root @ stationxx root] # tune2fs-j / dev/hda9
tune2fs 1.24a (02-Sep-2001)
Creating journal inode: done
This filesystem will be automatically checked every 31 mounts or
180 days, whichever comes first. Use tune2fs-c or-i to override.

In this way, the original ext2 file system on the conversion into ext3 file system. Note ext2 file system will be converted to ext3 file system, the district will be unnecessary Xie set down conversion.

Conversion is completed, do not forget to / etc / fstab file corresponding to the district from the ext2 file system changes to ext3.

ext3 log storage areas

Log can be placed in another storage device, such as storage to the district / dev/hda8. For example, to / dev/hda8 on the creation of a ext3 file system and logs stored in an external device / dev/hda2, is running the following order:

[root @ stationxx root] # mke2fs-J device = / dev/hda8 / dev/hda2

ext3 file system repair

New e2fsprogs in e2fsck support ext3 file system. When a ext3 file system was destroyed, the first unloading the equipment, then e2fsck repair:

[root @ stationxx root] # umount / dev/hda8

[root @ stationxx root] # e2fsck-fy / dev/hda8

All in all, ext3 log file system is the linux system from ext2 file system over to the log file system is a simple choice, and also the most concise way. Because it is directly from the ext2 file system developed from the system by the ext2 file system transition to ext3 log file system upgrade process smooth, offers the assurance data security systems. Linux to use the current system log file system, the way most insurance is to choose ext3 file system.