File System Types

ext2 Dont use this, use ext3. Has the concepts of blocks, inodes and directories.
ext3 Most popular, ok scalability. enhanced with journalling, supports POSIX ACL
reiserFS small files, scales bigger than ext3, made by guy who killed his wife and child
XFS extremely scalable, large files, Video, SGI irix
NTFS Microsoft journaled FS, general MS purpose
isofs Used by CDROM file system
Sysfs It is a ram-based filesystem initially based on ramfs. It is use to exporting kernel objects so that end user can use it easily.
Procfs It can be used to obtain information about the system and to change certain kernel parameters at runtime using sysctl command.

Dir Structure and Partitioning Best Practices

Following is descriptions of common unix dir’s and best practice partitioning of them

Dir Description Mount options, best practice
/ Root partition; incorporates the files under several dirs including /dev, /sbin, /tmp etc
/home Users home directory Set options local, nodev, nosuid, with quotas
/usr Stores application programs; Linux/BSD binary programs are installed here Set option nodev
/var Stores log files, mails and other; files which keep changing size (log, or caching files) Set option local, nodev, nosuid
/tmp Stores temporary files Set option nodev, nosuid, noexec option must be enabled

Following is the code in /etc/fstab

/dev/sda1  /home          ext3    defaults,nosuid,nodev 1 2

Following is the code from an example mount command. Just running mount, gives you currently mounted fs’s.

/dev/wd0a on / type ffs (local)
/dev/wd1a on /home type ffs (local, nodev, nosuid, with quotas)
/dev/wd0d on /root type ffs (local)
/dev/wd0e on /usr type ffs (local, nodev)
/dev/wd0f on /tmp type ffs (local, nodev)
/dev/wd0h on /var type ffs (local, nodev, nosuid)
/dev/wd0g on /var/log type ffs (local, nodev)

For more info please read man pages of fstab, mount, fdisk or

fstab options key

  • nosuid - Do not set SUID/SGID access on this partition
  • nodev - Do not character or special devices on this partition
  • noexec - Do not set execution of any binaries on this partition
  • ro - Mount file system as readonly
  • quota - Enable disk quota

Above options can be set only if you have separate partitions.

technology/unix/underpinnings.txt · Last modified: 03.17.2008 04:00 by
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