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itec 400 Backups

itec 400 Backups. George Vaughan Franklin University. Topics. Determining Backup Needs Backup Strategies Data Verification Storage Backup Media. Determining Backup Needs. Your Valuables (Data) research data billing, tax records customer data Your Insurance (Backups/Archives)

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itec 400 Backups

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  1. itec 400Backups George Vaughan Franklin University

  2. Topics • Determining Backup Needs • Backup Strategies • Data Verification • Storage • Backup Media

  3. Determining Backup Needs • Your Valuables (Data) • research data • billing, tax records • customer data • Your Insurance (Backups/Archives) • cost (money, interference with operations) • quality of insurance policy (backup process) • speed of recovery • type of disasters covered

  4. Determining Backup Needs • Can you tolerate the loss of everything? • Can you tolerate the loss of some filesystems or files? which ones? • How often is this critical data changing? • How long can you wait before it is restored?

  5. Determining Backup Needs • How old can the restored version be (hours, days, weeks)? • How much can you afford to spend on a backup strategy? • Does your system need to be available 24x7?

  6. Backup Strategies • Different Strategies may be applied to different filesystems. • 2 Types of backups • Full Backup • Incremental Backup

  7. Backup Strategies • Full Backup • Backup everything • Can take a long time • Can consume a lot of backup media • Simplest to restore from

  8. Backup Strategies • Incremental: • only backup files that changed since some point in time. • Faster Backups • Less consumption of backup media • More complicated restore process • Still need to do full backup every once in a while

  9. Multi-level backup • A popular strategy: multi-level backup • Level 0: Full Backup. • Level 1: Incremental backup since last level 0 backup. • Level 2: Incremental backup since last level 1 backup.

  10. Multi-level backup • Level 0: First Sunday of Month • Level 1: Every Monday • Level 2: Every Tuesday through Friday • If I accidentally deleted my directory on the 25th, which backups do I need?

  11. Data Verification • You never know how good your backups are until you need to restore. • You can’t wait till disaster hits only to find that your tape units were never working. • Need to periodically check/verify backups • against original files • on alternative machines • for backup media degradation

  12. Storage • Where should you store your backups? • Maybe store level 1 and level 2 in an alternate location? • What about archived data?

  13. Organization of Backups • Labels • Color Coded • Printed • Dedicated Shelf Location • By Day of Week? • By Week of Month? • 3rd Party Software • Stored separately?

  14. Backup Media

  15. Backup Tools • Tools/Commands to facilitate backups: • tar • cpio • dump/restore • amanda

  16. tar • tar - tape archive utility • a tar file is a file that contains other files and directories, plus information about them, such as their file name, owner, timestamps, and access permissions. • The archive can be another file on the disk, a magnetic tape, or a pipe. used to store and extract files from ‘tarfile’ • commonly used to for creating a tarfile on disk

  17. Example: Creating a tar File • Solaris example: create a compressed tarfile containing the directory ‘myDir’: • First, create the tar file from the directory “myDir”: tar cf myDir.tar myDir -Next, compress the tar file, for easier distribution and/or storage gzip myDir.tar -Finally we end up with a compressed tar file named, “myDir.tar.gz”

  18. Example: Unpacking a tar File • Solaris example: create a directory from a compressed tarfile named ‘myDir.tar.gz’: • First, uncompress the the tar file: gunzip myDir.tar.gz -Next, untar the file. This will result in a directory named myDir tar xf myDir.tar

  19. cpio • cpio - copy in and out of archive • copies files into or out of a cpio or tar archive • cpio has three operating modes: • copy-out - copies files out to archive • copy-in - copies files in from archive • copy-pass - copies files from one directory tree to another without creating intermediate archive

  20. Example: Creating a cpio File • Solaris example: create a compressed cpio file containing the directory ‘myDir’: • First, create the cpio file from the directory “myDir”: find myDir | cpio -o > myDir.cpio -Next, compress the cpio file, for easier distribution and/or storage gzip myDir.cpio -Finally we end up with a compressed cpio file named, “myDir.cpio.gz”

  21. Example: Unpacking a cpio File • Solaris example: create a directory from a compressed cpio file named ‘myDir.cpio.gz’: • First, uncompress the cpio file: gunzip myDir.cpio.gz -Next, unpack the cpio file. This will result in a directory named myDir cpio -imd ‘myDir’ < myDir.cpio

  22. dump/restore • The dump and restore commands are used collectively • More sophisticated than tar, cpio • Supports multi-level backups • Records backup history in /etc/dumpdates • restore supports interactive mode

  23. 0009: dump -0 -u -f /backup/home_0 /home 0010: DUMP: Date of this level 0 dump: Mon Mar 10 23:08:54 2003 0011: DUMP: Dumping /dev/hdb2 (/home) to /backup/home_0 0025: DUMP: finished in 39 seconds, throughput 6498 kBytes/sec 0026: DUMP: Date of this level 0 dump: Mon Mar 10 23:08:54 2003 0027: DUMP: Date this dump completed: Mon Mar 10 23:10:48 2003 0028: DUMP: Average transfer rate: 2283 kB/s 0029: DUMP: DUMP IS DONE Line 9: perform level 0 (full) backup of /home filesystem and store in file /backup/home_0 Lines 10-29: output of dump Example of dump/restore

  24. 0031: # cat /etc/dumpdates 0032: /dev/hdb2 0 Mon Mar 10 23:08:54 2003 0034: # dump -1 -u -f /backup/home_1 /home 0035: DUMP: Date of this level 1 dump: Mon Mar 10 23:14:32 2003 0060: rm -rf dummy Lines 31-32: Look at contents of dumpdates Lines 34-35: Perform level 1 (incremental) backup Line 60: The act of much regret… Example of dump/restore

  25. 0062: # cd /home 0063: 0064: # restore -i -f /backup/home_0 0065: restore > ls 0066: .: 0067: dummy/ dummy1/ gvaughan/ johnsonm/ lost+found/ 0068: 0069: restore > add dummy 0070: restore > extract 0071: You have not read any tapes yet. 0072: Unless you know which volume your file(s) are on you should start 0073: with the last volume and work towards the first. 0074: Specify next volume #: 1 0075: set owner/mode for '.'? [yn] n 0076: restore > quit Line 62: cd to filesystem Line 64: restore for level 0 backup Example of dump/restore

  26. 0082: # restore -i -f /backup/home_1 0102: # cat /etc/dumpdates 0103: /dev/hdb2 0 Mon Mar 10 23:08:54 2003 0104: /dev/hdb2 1 Mon Mar 10 23:14:32 2003 Line 82: Complete restore from level_1 backup. Lines 102-104: Look at contents of /etc/dumpdates Example of backup/restore

  27. Amanda • amanda - Advanced Maryland Automatic Network Disk Archiver • Developed at University of Maryland • Client/Server model • Multiple clients can be backed up onto a single backup server. • Uses a combination of full and incremental backups.

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