IBM Support

Mirrorred Disk Protection Levels

Troubleshooting


Problem

This document describes Disk (DASD) Mirroring - Levels of Protection.

Resolving The Problem

This document describes Disk (DASD) Mirroring - Levels of Protection.

There are several different levels of mirrored protection. Here is the hierarchy from best to lowest:

1. Remote
2. Ring (HSL)
3. Tower (also called Frame)
4. Bus
5. IOP
6. IOA
7. IO-Bus
8. Controller
9. Device

Ring level means the disk units in the pair are on different HSL loops.

Tower level means the disk units are in different physical towers. Tower level is lower than Ring level because there could be many towers on one HSL loop.

With Ring level mirroring, an entire tower could fail and the system (or partition) would not go down. There is additional information available on this subject at the following Information Center URL:

http://www-01.ibm.com/support/knowledgecenter/ssw_ibm_i/welcome

From this site, you should follow the topics below:

1. System Management ->
2. Disk Management ->
3. Plan for Disk Management ->
4. Plan for Disk Protection ->
5. Plan for Mirrored Protection ->
6. Determine the level of desired protection.

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Historical Number

371349615

Document Information

Modified date:
08 April 2025

UID

nas8N1015650