Linux下如何使用磁带机

1 INDETIFY YOUR TAPE BACKUP UNIT RedHat Linux supports many different kinds of tape devices Typically SCSI tape devices will be named dev st0 dev st1 etc IDE tape devices will be named dev ht0 dev ht1 etc If the device name has an n in front of it like dev nst0 for example then it is a No rew ind device The device will not rewind automatically after a utility like dump or tar is finish ed writing to it Identify the TBU in your system with the following command cat proc scsi scsi Notice the information that this file contains Vendor Model Firmware revision and access type 2 CONTROLLING THE TAPE DEVICE The mt utility can be used to control the tape device Mt is installed with package mt st 0 5b 10 src spm mt usage mt v h f device command count You can use the f switch to specify a tape device For example to eject a scsi tape from your tape backup u nit type the following command mt f dev st0 offline The mt command will default to dev tape if no f switch is used Create a symbolic link between dev st0 and dev tape for ease of mainte nance ln s dev st0 dev tape mt offline Erase a tape with the following command mt erase The mt status command is similar to the command tape status in SCO OpenServer mt status Rewind a no rewind tape device with the following command mt rewind Mt commands are often used in backup scripts Some versions of Linux also include a remo te version of mt called rmt The use of rmt is not recommended in secure environments 3 BACKUP TO TAPE USING TAR The tar archive program is frequently used to backup data to a TBU Tar is a popular backu p solution because it compresses data Tar can be installed with package tar 1 13 17 8 src rpm Perform a backup of the home directory using the tar command tar cvf dev st0 home Verify the contents of the tape using tar tar tvf dev st0 Restore the contents of the tape using the tar command tar xvf dev st0 Notice that the contents of the tape restore to your current working directory The restored data can be compared with the original data before it is overwritten Tar archives can be further compressed with gzip tar zcf dev st0 home Extract the zipped archive with the following command tar zxf dev st0 4 BACKUP USING CPIO Cpio is another popular backup solution Cpio can be used to copy files into or out of an exi sting tar or cpio archive Cpio can backup or restore data incrementally This utility can als o be used to sort archived data by file name owner timestamp and access permissions Cpio can be installed with package cpio 2 4 2 20 src rpm Cpio operates in 3 modes copy out mode copy in mode and copy pass mode Use copy out mode to write a file to t he tape drive Copy out mode is frequently used with the find command For example find tmp cpio ocv dev st0 Verify the backup cpio tvF dev st0 Use copy in mode to restore archived data from an archive destination file The restore will not overwrite files that are more or the same age without a force switch cpio icv dev st0 Verify the contents of the tape tar tvf dev st0 Perform a restore cpio ivH tar dev st0 Notice that the cpio restore in tar format restores to the current working directory 5 BACKUP USING DUMP RESTORE Dump Restore are utilities that were developed specifically for use with the ext2 file syste m Dump can be used to perform full or incremental backups However because dump is t ypically used for full restores because it was designed to back up entire partitions The dump and restore utilities can be installed with package dump 0 4b19 4 src rpm Back up a full partition with the following command dump 0u f dev st0 example1 Since dump is designed to back up incrementally you should always start with a level 0 ba ckup The u switch updates the files etc dumpdates cat etc dumpdates Next create a new file touch example1 hello Since the directory has changed insert a new tape and perform a level 1 dump to backup everything since the last level 0 dump dump 1u f dev st0 example1 Notice that etc dumpdates has been updated to reflect the newest backup cat etc dumpdates The restore utility can be used to restore should the partition fail To perform a restore cre ate the new partition mount it and format the partition with the ext2 file system using th e mkfs command Next insert the dump le