Importance of Routine File System Backups To prevent loss data due to: Accidental deletion of files Hardware failures Problems with re-installation or system upgrades System crashes System break-ins by unauthorized users, compromising data integrity Natural disasters

Tape Media Types

Tape Drive Naming “/dev/rmt/#hn” “#” - Logical tape number “h” - Tape density “l” - Low “m” - medium “h” - high “c” - compressed “u” - ultra compressed “n” - No rewind

Tape Drive Control Using the “mt” command “mt status” - Displays the status information about the tape drive “mt rewind” - Rewinds the tape “mt offline” - Rewinds the tape and, if appropriate, takes the drive unit offline and if the hardware supports it, unloads “mt fsf count” - Moves the tape forward count records Usage “# mt -f /dev/rmt/0n fsf 2”

Strategies for Scheduled Backups To set up a backup schedule, determine: The file systems to backup A backup device The number of tapes to use for the backup The type of backup The procedures for marking and storing tapes The time it takes to perform a backup

Determining the Number of Tapes To determine the size f the file system, use the “ufsdump” command with “S” option: “#ufsdump 0S /export/home” - Displays the size of the Full backup for the “/export/home” filesystem “#ufsdump 3S /export/home” - Displays the size of the Incremental backup (level 3)

The “/etc/dumpdates” File Records backups if the “-u” option is used with the “ufsdump” command. Each line in the file shows the file system that was backed up and the level of the last backup. It also shows the day, the date, and the time of the backup. When incremental backup is performed, the “ufsdump” command consults this file, it looks for the date of the next lower-level backup.

The “ufsdump” command Command format: “ufsdump options argument(s) filesystem_name” Remote Backup “ufsdump options remotehost:tapedevice filesystem”

Options for the “ufsdump” command “0-9” - Back up level. Level 0 is full backup of the file system, Level 1 through 9 are incremental backups of files that have changed since the last lower-level backup. “v” - Verify. After each tape is written, the system verifies the contents of the media against the source file system. “S” - Size estimate “l” - Autoload

“o” - Offline. When the backup is complete, the system takes the drive offline, rewinds the tape. “u” - Update the /etc/dumpdates file. “n” - Notify. Send messages to the terminals of all logged-in users who are members of the “sys” group. “f device” - Specify the device name of the filesystem backup (default will be “/dev/rmt/0”)

Usage “#ufsdump 0uf /dev/rmt/0 /export/home” “#ufsdump 0uf host2:/dev/rmt/0 /export/home”

Guidelines Bring the system to single-user mode Unmount the file system Check the file system using “fsck” Then perform a full backup of the file system