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Chapter 10. Managing the File System. The File System and Disk storage . The file system is the structure and organization of data on a data storage device. The good file system support provide Linux users to access files on file system used by other operating systems.
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Chapter 10 Managing the File System
The File System and Disk storage • The file system is the structure and organization of data on a data • storage device. • The good file system support provide Linux users to access files on • file system used by other operating systems. • The Kernel document for file system is at /usr/arc/linux-2.4/ • Documentation/filesystems/. • The Starting block is special block containing boot sector. Refer to page 276-277 for file system Support and partition
The Main Categories of File System • Network File System- This file system is physically stored somewhere other than your local computer but appear as if they are mounted on your local machine. E.g NFS, Coda,InterMezzo, NCP,SMB…. • Local File System-This is found on a physical device, they are the hard drive in your • desktop or laptop computer.E.g FAT,ext2,ext3…. To check and fix a File System • fsck • fsck /dev/hdc • By default the system will run fsckafter a number of reboots. To View Your System’s File Systems Support cat /proc/filesystems All the file systems will be shows that your system support
Advantages of file system ext3 • Easy transition form ext2 to ext3 by the command • tune2fs /dev/hdxn -j. • Its possible to recover a deleted file from an ext3. • Ext3 can accommodate files larger as 2TB. • Directories are large as 2TB. • Maximum file name length of 255 characters, but can be increased. • Ext3 can allocate and use empty space in a very efficient manner. • The use of space is so efficient that ext3 does not need de-fragmenting. • When a file is deleted , its inode is erased and the data blocks associated • with it are freed. • Ext3 file systems were designed to follow UNIX design concepts. • The disk fix command fsckis not necessary in ext3.
Some other file system • (ReiserFS)- It offers similar features toext3, but there is no easy migration path from an already existing ext2 to ReiserFS. • JFS and XFS- IBM has provided its journaled file system (JFS) that is used • with its commercial UNIX named AIX. Silicon Graphics has provided its • XFS file system used by its commercial UNIX named IRIX. • DOS- window FAT and FAT32. • CD-ROM file system • iso9660 • universal Disk Format (UDF)
Creating and to view a File System • fdisk /dev/hda • It will show the file system information of hard disk naming hda • By the key ‘m’ you can see complete help how to use fdiskcommand. • By the key ‘n’ you can create new partition, and in different steps you will give relevant • input e.g the size and name of partition … • sfdisk /dev/hda • same like fdiskcommand but it offers relaxation for you , it offers a script support file in • which you can set the rules of partition and then the system will automatically do the • partition according to the rules . • prevent accidents caused by inexperienced users like me . • Some more commands are: • parted • mke2fs • dumpe2fs • to examine the structure of your ext3 file system • mkfs.ext3 • to create ext3 partition type • e2fsck • to check the bad blocks and mark them as bad
Installing a new Drive • There might comes a situation when the physical disk become full, adding • another drive and moving part of the filesystem there is not that much daunting • task. • JUMPER SETTINGS • BIOS • THE fdisk COMMAND • FORMATTING • CREATING DIRECTORIES FOR NEW HARD DISK • MOUNTING • COPYING THE DATE INTO NEW HARD DISK cp • PERMANENT MOUNTING etc/fstab
Mounting Automatically • The super user only can mount file system permanently by editing a file • /etc/fstab/ • GUI tool to mount • kwikdisk &
Mounting a Partition as Read and Write • mount -o ro, /hda2 /home (mounted as read only) • mount -o rw, /hda2 /home(mounted as read only) To set and Tune the Settings of Hard Disk • hdparm(used by super user) • hdparm command device
The /dev/null Mistery • more mybigfile > /dev/null (this big file having 5GB approx data will vanish) Redirecting standard out put The sign > is used for redirecting standard output. The sign 2> is used for redirecting standard error. standard output standard error Redirecting output on a file Redirecting error on a file