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Dirk Krause — Thu, 21 Dec 2023 18:18:10 -0000

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dk-bmm modified by Dirk Krause

Dirk Krause — Fri, 28 Jul 2023 21:35:04 -0000

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 #  dk-bmm — Manage backup media
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 ## Description

dk-bmm modified by Dirk Krause

Dirk Krause — Fri, 28 Jul 2023 20:04:36 -0000

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+← Previous ↑ Home ↑ Programs → Next
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+#  dk-bmm — Manage backup media


+## Description
+
+The dk-bmm program simplyfies backup media management.
+
+A *backup* is a set of copies of a file or directory made for security reasons to prevent loss of data.
+A backup is never on the same disk as the original file as a failing hard disk will cause loss of original file and copy.
+A backup media is normally not available for writing to the computer (except while making backups). Otherwise malicious software could damage the original file and the copies.
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+A *backup media* is a storage device (i.e. DVD-RW, tape, or remote directory) used to save the copies.
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+A *media set* is a set of 10 such storage devices.
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+A *backup set* is a collection of files and directories saved together. Typically a backup set corresponds to a media set.
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+A *backup cycle* is a cycle of 200 backup operations on a media set. Each media is used 20 times. After completing a cycle the media differ in age. You always have media 1, 2, 3, or 4 backups old, the remaining media are older.
+After completing a cycle you should switch to a new media set but keep the media from the completed cycle.
+
+The dk-bmm program performs the following four operations:
+
+* Retrieve name of current backup media set (option -s).
 
+* Confirm that backup to current media set was finished successfully (options -s and -c).
 
+* Retrieve number of current backup media (default operation, neither -s nor -c required).
 
+* Confirm that backup to current media was finished successfully (option -c).  
 
+
+---
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+## Example
+
+Imagine a university faculty file server. We have the following backup sets:
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+Name Description
A Students home directories
B Staff member home directories
C Servers configuration files
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+We decide to make copies for set A three times a week, for set B and C once a week.
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+So our set names file set-names.txt looks like:
+
+~~~
+A B A C A
+~~~
+
+Each time we make a backup we retrieve the current backup set name first:
+
+~~~bash
+SETNAME=`dk-bmm -s set-names.txt`
+~~~
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+Next we have to find the media number within the set:
+
+~~~bash
+MEDIANO=`dk-bmm set-$SETNAME.txt`
+~~~
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+Now we can ask for the media:
+
+~~~
+echo Please insert and mount $SETNAME $MEDIANO
+~~~
+
+Depending on the set name we decide, what to do:
+
+~~~bash
+case "X$SETNAME" in
+"XA")
+  tar czf /media/…/A.tar.gz /home/students
+;;
+"XB")
+  tar czf /media/…/B.tar.gz /home/stuff
+;;
+"XC")
+  tar czf /media/…/C.tar.gz /etc
+;;
+esac
+~~~
+
+After finishing successfully we first confirm the media number:
+
+~~~bash
+dk-bmm -c set-$SETNAME.txt
+~~~
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+Now we confirm the backup set:
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+~~~bash
+dk-bmm -s -c set-names.txt
+~~~
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+Finally we write a media number report:
+
+~~~bash
+dk-bmm -r set-$SETNAME.txt > report-$SETNAME.txt
+~~~
+
+In a real-world example one would use automation, i.e. do the backup outside working hours and send the request to insert next tape or media for next backup by e-mail…
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+---
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+## Manual
+
+See the [dk-bmm manual] for the full documentation of the program.
+
+---
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Name	Description
A	Students home directories
B	Staff member home directories
C	Servers configuration files

dk-bmm modified by Dirk Krause

Dirk Krause — Fri, 28 Jul 2023 18:42:08 -0000

Recent changes to dk-bmm

dk-bmm modified by Dirk Krause

dk-bmm modified by Dirk Krause

dk-bmm modified by Dirk Krause

dk-bmm modified by Dirk Krause