BCV-Backup-Script

BASH script to control backups of EMC Symmetrix BCVs.

Why is it here:

This script is here for preservation mostly. It is not intended to be used by anyone, because the technology it was used on was popular in the late 1990 and early 2000s. I doubt you would find these systems in a production environment anymore. I started the scripting in 2001 or 2002. It went live in 2002. I understand it ran for quite a while after I left.

How it was used:

The main script is bin/BCV_Est.sh. It is named in this mixed case to try to prevent accidental execution. There are several commandline options built in including help to print a usage message. In fact entering just the script with no options would execute a usage message and exit.

The main, and required, configuration file is etc/bcv_scripts.conf, and each section is, hopefully, clearly explained.

My requirements for the script:

Being the lead SysAdmin as well as the BURA and Storage admin, I had several criteria for the script.

1. One script to rule them all. I wanted to be able to backup any BCV group with the same script. I did not want to have a separate script to run for each BCV group.

2. I wanted only one configuration file to control any and all BCV backup.

3. There were 3 BCV groups at the time: I wanted to be able to run 3 instances of the script at the same time without them stepping on each other.

4. I wanted to run the script automatically or interactively.

5. Everything was to be handled by functions. This allowed me to work on the various parts of the script one at a time and test them without impacting other functions. It also allowed code reuse throughout, and, I think, made it more understandable to my co-workers.

6. I wanted all of the functions to be in external files from the main script, so it would not be unbearably long. All the main script would do is call functions.

7. I wanted the script to define a variable once using the information in the configuration file or information it gathered as the script ran. The required some quasi-OOP in Korn shell. I did not want each function to have to reinitialize each variable it required; do it once and make it available to the whole script environment.

8. I wanted detailed logs of every phase.

9. I wanted role-based notification, so I could get a full report, send just the necessary info to the DBAs, and error notifications to operations.

10. I wanted error checking on every step the script took. Automation is great, but only after it has been tested to make sure it does not break other things while it does its assigned task.

11. strict control of the LVM, BCV, Oracle, and OmniBack processes and procedures.

What it did:

This script controlled the backup of three sets of Business Continuance Volumes (BCV) on an EMC Symmetrix storage system. The BCV is like a 3rd mirror of the data that can be attached and detached from the mirrored pairs dynamically. When attached, you run commands to sync them with the mirrored pairs called Standard disks or devices. Then you detach them, and mount them on another server to be backed up to (in those days) tape. The sync'ing could be full or incremental as you wished.

In the environment I ran at the time, there were three groups of BCVs, and each one connected to a separate Oracle database server. They had to be mounted on the HP-UX servers running Oracle, and they sync'ed up with the current state of the database filesystem. Then they were detached, unmounted, and remounted on another HP-UX server running HP's OmniBack II backup software. The entire process had many points in which problems could occur.

IT management, and I wanted the whole thing automated, but I would not let them hire out the process. Since I was the main admin of the environment, I wanted it to work my way, and in a way that I could understand and fix myself. KSH was the only thing I knew well enough to script in at that time.

The main, and required, configuration file is etc/bcv_scripts.conf, and each section is, hopefully, clearly explained.

======= The filesystems for the databases and for the BCVs were LVM based. Backups were controlled by another HP-UX server also connected directly with the Symmetrix. At night the BCVs would be mounted on the database servers while they were being synced with the databases, then unmounted, and mounted on the backup server. This was done so that the backup process, which ran during the morning hours, and its agents, did not impact the load on the database servers. Mounting and unmounting the BCV Volume Groups needed to be done correctly according with LVM best practices, or eventually the LVM structure would get corrupted.

One of the more critical parts of controlling the LVM filesystems came when new disk devices were added to a database filesystem. This required that the LVM Volume Group structure of the BCVs had to be dismantled and reassembled before they could by synced with the standard devices. A special part of the script was used if this was the case, and it was controlled by the configuration file.

Along with the LVM control, proper control of the Oracle hot backup process, and the Symmetrix process of attaching, syncing, and detaching BCVs, everything had to be performed according to the official procedures as published by the vendor.