In computing, the file system is used for management. Without it, the information placed in the storage area will be one large amount of data with no way to indicate where one piece of information stops and the next begins. Dividing information into separate parts and giving each part a name allows it to be easily hosted, transported and identified. The structure and logical conditions used to manage groups of information and their names is called a "file system". Today files are available to users: F2FS, EXT4, VFAT, Fat32, Exhibit, EXT3, EXT2, NTFS.
File system variations
EXT2 Files - This was the first commercial Linux system that did not support journaling. Suitable for SD cards and USB sticks as it has high performance and low write volume. USB and SD storage are limited to write cycles,so this format is best suited for them. Limits:
- Custom file size from 16 GB to 2 TB.
- System size 2TB to 32TB.
- Limits are calculated based on the block size used.
- The block size varies from 1 KB to 8 KB. For example, if a block size of 1 KB is used, the maximum file size can go up to 16 GB, and for 8 KB, 2 TB.
- The average range size is 2KB and 4KB, which has a file size of 256GB and 2TB.
The EXT3 file system is designed to overcome the limitations of EXT2 with journaling support. It tracks changes to files, which aids in fast recovery and reduces the chance of data loss in the event of a system crash.
Limits:
- Custom file size from 16 GB to 2 TB.
- Size 4TB to 32TB.
- Upgrade FS from EXT2 to EXT3.
- EXT4 is the fourth advanced system designed to overcome the limitations of EXT3, introduced in 2008 by the development team. The latest in the ext family with journaling support and many new features.
- Backwards compatible.
- Permanent pre-allocation to select file system.
- Delayed selection.
- Unlimited number of subdirectories.
- Log checksum.
- Quick check FS.
- Transparent encryption.
- Limits: Individual file size from 16 GB to 16 TB. Size up to 1EB.
- FS update not required. From-For backward compatibility EXT2, EXT3 can be directly mounted as EXT4.
Linux FS: EXT2, EXT3, EXT4 file system.
| Parameter | EXT2 | EXT3 | EXT4 |
| Year of introduction |
1993 |
2001 | 2008 |
| Designed by | Remy Card | Stephen Tweedy | Development Team |
| Journaling | Unavailable | Affordable | Affordable |
| Individual file size | 16 GB to 2 TB | 16 GB to 2 TB | 16 GB to 16 TB |
| File system size | 2TB to 32TB | 4TB to 32TB | up to 1 EB |
| Refresh | Can be done online via EXT3. Can be mounted as EXT4. No update required | Can be mounted as EXT4. No update required | Not available |
Features of EXT3 files
EXT3 expands on the popular EXT2 with the introduction of a magazine. This is essentially the "intention to commit" data. The amount of information logged is configurable and varies to log what is known as "metadata". After updatelog, the system records the actual data in the relevant areas and marks the log entry to fix it.
After a crash, the system can be brought back online very quickly using the log, which reduces the number of minutes using fsck, with the added benefit of significantly less chance of data loss or corruption. When a file is attached to a file, the last snapshot of that file is read from disk into memory. At certain points, the EXT3 file system will update file data on disk from pending log entries and truncate those entries from the log.
Copying operations and synchronizing them in the journal with its associated system is called a checkpoint. It is usually changed by formatting the storage in a different format and using a PC, or by custom recovery. A recovery like TWRP does not allow you to change them by default, whereas a CWM recovery allows the user to select a system with no extra effort. Available systems are determined by the kernel developer.
Formation process
A file system is a method of organizing information on a computer. In Linux and other Unix-like systems, such as the Android file system, the basis is a directory hierarchy that starts at the root directory and is denoted by a slash and contains a series of subdirectories, each of which, in turn, can contain additional ones. EXT2 is the simplest and most portable native Linux system because it is the easiest to transfer data. She wasdeveloped as an improved version of the extended system and was incorporated into the OS kernel and is still widely used.
The log form maintains a special file called the log that is used to recover any inconsistencies resulting from an improper shutdown of the computer and thus always maintains internal consistency. These shutdowns are usually due to a power interruption or software failure that cannot be resolved without a reboot.
EXT3 file system adds to its predecessor:
- Magazine.
- H-tree directory indexes (hashed tree).
- Types of files in directory.
Without them, any EXT3 file system is effectively an EXT2 file system. This allowed the use of proven and mature filesystem maintenance utilities (eg fsck) to maintain and repair EXT2 filesystems that can be used in EXT3 without major modifications.
Logging options
An EXT3 journal must not reside on the same physical device as the file system it registers. On RedHat Linux, the journal device can be specified using the journal_device=option, with the -journal-options command line argument of the tune2fs utility.
EXT3 file system provides three options:
- Writeback - great speed at the price of limited data integrity. Allows you to display old data in files after a crash and rely onstandard kernel backups for flushing buffers.
- Ordered data is compatible with the system - new files that do not have garbage after a crash.
- Logs are data that require more space and slower performance. The most secure data retention policy.
Problem using the system
If a user creates a Linux EXT3 system on an entire disk that is not initialized, there is a risk of failure because it is not created on a partition but on a second SCSI disk. Before fixing a file system error, perform operations:
- Enter: fdisk -l /dev/sdb.
- Creates an ext3 system with volume label "/newfs" on a hard drive with no partition: mkfs -t ext3 -L / newfs -v /dev/sdb.
- Mounting a new ext3 system: mount -t ext3 / dev / sdb / newfs.
- Run umount /newfs: mount -t ext3 LABEL=/ newfs / newfs.
- It's better to create an EXT3 system on a partition rather than a hard drive directly if the second SCSI hard drive was initialized with one primary Linux partition before running the mkfs command.
- Run: fdisk /dev/sdb, mark 'n' to add new partition 'p' for main partition, '1'.
- For partition number 1, before fixing the file system error, press ENTER twice to accept the default value and effectively allocate the entire hard disk for the main partition, "w" and create a partition table.
- Run mkfs -t ext3 -L /newfs -v /dev/sdb1 to create an EXT3 system on the primary partition (/dev/sdb1).
- Now one of these two mount commands will work without errors: mount -t ext3 / dev / sdb1 / newfs mount -t ext3 LABEL=/ newfs / newfs, after adding this line to / etc / fstab: LABEL=/ newfs / newfs ext3 by default.
- Linux will then automatically mount this new system on every reboot, or you can run it via mount /newfs on the root command line.
You can use File Scavenger TM to recover data from an external volume when it becomes corrupted or is accidentally deleted. In these situations, the file system metadata remains intact and recovery is possible. Raw recovery is possible for an ext4 volume when deleting a file or reformatting the volume.
Another great data recovery software is Quick Recovery for Linux. It is a handy tool for users who are facing data loss in Linux operating system. The software works in fully automatic mode and provides fast recovery for files lost due to accidental deletion, physical damage, OS crash, logical errors, improper shutdown and more. It sincerely recovers all deleted, corrupted, formatted or lost data from any of the data loss events
Fix latency issues
EXT3, being the standard for almost all installed Linux systems, including the Android file system, is well tuned forperformance. However, there are some performance issues with EXT3, especially where the fsync() system call is used. The problem is that EXT3 when run in data mode when some processes call fsync() to clear the data on disk. This problem is best known, for example, in the form of Firefox system lag.
The first fix is to mark I/O requests generated by fsync() with the WRITE_SYNC op bit, marking them as synchronous requests. The CFQ I/O scheduler runs synchronous queries. Generally, reads are considered synchronous, while writes are not. Once synchronized fsync() requests are synchronized, they can proceed to normal I/O.
This makes fsync() much faster by slowing down tasks that require I/O on the system. In addition, the CFQ scheduler uses "forward" logic with synchronous requests. After executing one such request, it will stop the queue to see if an adjacent request appears. The idea is that the disk head will be ideally positioned to satisfy this request.
Ext2Fsd File Loader
You can install Ext2Fsd on a Windows machine and it will provide access to these systems. This simple tool supports the following features:
- Write access for reading ext2 / ext3.
- Replay ext3 log on mounting.
- Mount point settings.
- Inode size: 128, 256.
- File sizeover 4G.
- Sharing CIFS over the network.
- Indexing htree directories.
Works with Windows 2000/ XP/ 7.
Program installation:
- Download the installer package. If a compressed version of the file was downloaded, decompress it.
- Double click on Ext2Fsd-XXX.exe (XXX is the release number).
- Perform the first steps of the installation wizard.
- When the "Select Additional Tasks" screen is reached, check all three windows and click the "Next" button.
- Finish the installation wizard (other steps are standard).
Enable file installation in Windows
After the ext2 / 3 disk is connected, the PC will not see anything. The user needs to tell the application how to handle the drive manually by assigning the drive. This can be done in one of three ways:
- Insert a disc using a special adapter that allows you to connect the drive to the USB port on the machine. It does not matter how it will be done if the machine recognizes the physical disk. Launch the application.
- Go to the beginning of All Programs, then | ext2fsd | Ext2 Volume Manager to start.
- When the main application window opens, find the newly connected disk, it will have the file system EXT2, EXT3.
- Press the OK button.
- Press the Done button.
If the user right-clicks the same drive and selects the "Manage Ext2" option, you canconfigure this drive at a narrower level. The following options are available:
- Volume in read-only mode.
- Installing a read-only disk Codepage.
- Change the disk code page, such as iso8859-1, utf8, acsii, etc.
- Install drive and letter: select a drive to mount automatically and drive name.
Direct use of Win7/8/10 documents
If using a PC with both Windows and GNU installed. Linux OS stores many documents, music files and movies on ext3 / ext4, the user can read and use them directly from Windows. Below are a few programs that allow you to mount an EXT3 file system on Windows (free):
- Ext2Explore (also known as Ext2Read) is probably the best historically known Windows driver that makes Linux ext FS read Explore2FS - a tool for GUI analysis and access to ext2 and ext3. It works under all versions of Windows and can read almost any system.
- Disk Internals Linux reader is a free tool to read and extract files from EXT2 / EXT3 / EXT4, HFS, UFS2, Reiser4 and ReiserFS partitions on Windows.
- ParagonExtFS is a proprietary software that has a version for Win OS and Mac (also supports installing Linux blocks for Mac). Read copy files from Mac OS HFS+ system to Windows. Apple has a Boot Camp driver package that allows Mac OS HFS+ to be visible from Windows.
For peoplewho do not intend to constantly read HFS + data, it is better not to download Boot Camp, but to use HFSExplorer and the target file system of the flash drive.
Boot Camp and HFSExplorer allows you to read data from a Mac OS read-only system. If you want to write to an HFS + system from Windows, you will need: Own Paragon HFS + (or) MacDrive from Mediafour
Troubleshooting Acronis file crash
Acronis Disk Director can split a disk into as many parts as needed without losing any data. The program allows you to easily convert, merge, divide and resize volumes. It also makes it easy to copy files and volumes to where they are needed. The user interface makes it easy to complete tasks through an intuitive design. It can format the drive with any of the following systems: FAT32, EXT2, EXT3.
However, there are times when the EXT3 file system crashed after Acronis. One of the causes of Acronis EXT2, EXT3 partition backup error, when some partitions contain errors and can only be displayed by sector, may be system corruption. Fixing this kind of crash can be done by backing up Ext2, Ext3 Linux partitions. Need to check partition for bad blocks: -vs /dev/sda 99.
The next failure is the "source disk cannot be empty" error. Problem: One disk from a RAID array dies using an Acronis boot disk that tries to create a backupa copy of the RAID and gives a "source drive cannot be empty" error. To repair file system corruption, if the system does not boot, try autoloading, then perform a backup under Windows, and if this does not help, then use the sector-by-sector backup approach.
As you can see, the control system is used by the user in the form of a nominal information base, which is easily placed, transferred and identified. The newly created journaling form, which is indispensable in repairing any inconsistencies in the operation of the computer, ensures internal consistency - this is the essence of the EXT3 file system.
