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Cosc 4750

Backups. Cosc 4750. Why Backup?. In case of failure In case of loss of files User and system files Because you will regret it, if you don’t. DUMB = Disasters Usually Motive Backups. How to backup. You want to pick a reasonable interval to backup Every night, once a week, once a month?

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Cosc 4750

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  1. Backups Cosc 4750

  2. Why Backup? • In case of failure • In case of loss of files • User and system files • Because you will regret it, if you don’t. • DUMB = Disasters Usually Motive Backups

  3. How to backup. • You want to pick a reasonable interval to backup • Every night, once a week, once a month? • What to backup? • user files, system configuration? • Where to store you backups? • on-site, off-site, next to the computer? • When do you backup? • During the day, night ?

  4. Always assume the worst case. • The computer caught fire and burned down the server room and the building. • What should you have backed up? Where should the backups have been stored? • In a perfect world, everyone would backup everything daily, onto a single tape (stored in the next state in a fire proof vault). • Rarely possible or even needed.

  5. What to use? • Most use a tape device • 8MM, 4MM, DLT, AIT, LTO, etc. • Floppy disks? • Zip disks? • CD, DVD ? • Removable hard drives? • RAID, with backups as well. • A lot depends on need and cost.

  6. Full and Incremental backups • Full • The entire area you want to backup. All the files are stored on “tape” • Incremental • Only those files that have changed are written off to “tape”, since the last full backup • There can be many incremental backups between full backups.

  7. Hardware backups • RAID devices. • Could choose to use RAID 1 (disk mirroring) • RAID 5, a lost disk, the "volume" can be recreated. • Lessens the change of disk failure and system lost • RAID does not prevent lost of data by users deleting files. • You would still want to perform a full backups every so often.

  8. Backup products • By default dump and restore are installed on UNIX systems. • dump will write a filesystem to a backup device • restore will restore a file/filesystem to the hard drive • You can use tar • Will “tar” files off to a backup device or to a file that can be copied somewhere else.

  9. Can use dd • Normally used to copy an entire filesystem from one hard to another or tape. • Used to “mirror” drives. • Amanda (Advanced Maryland Automatic Network Disk Archiver) • Use a single large-capacity tape drive on a server to backup files from multiple computers over the network.

  10. Commercial Software • There is a lot of it. The book lists a couple and a web site for the rest. • Computer Science uses a program called bru for UNIX backups. • Command line and GUI interface. • Can script the backups

  11. Backup storage • Backups by their nature, break all security and permissions. • The entire tape is readable by whom ever has the tape. • Security and safety of the tape must be dealt with as well. • Tapes are also vulnerable to electric magnetic fields (such as the seat warmers in most cars)

  12. What to backup? • Systems files and users files, but • Do need to backup the kernel? Or just configuration files? If so, which ones? • Do you really need to backup users MP3 collections? Their .jpg collections?, etc. • What about other stuff, such as commercial software, where you have the install media? • Most products allow you be selective about what you backup, with a Don’t backup list, (usually wildcard list).

  13. Users Backup • Users may want backup their stuff as well. • "personal" backups. • rsync is program that can maintain copies of directories over the network. • What kind of rules are setup? • tapes, when, etc.

  14. Q A &

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