IBM ShopIBM Support Download
HomeNewsProductsservicesSolutionsAbout IBM
Search 
  in  


IBM Server Products
Overview
How to Buy
Support

Select a Language
 Online Assistant
 Discussion Forums Warranty Status Lookup

Technical Information
 Downloadable files
 Hints and tips
 Hot news
 Online publications
 Parts information
 Product information
 OS installation

Quick Path
Survey
 Support Home
Login Profile My Page Ask an Expert Help
 
Servers - Strip size setting for SSA RAID
Applicable Countries
Worldwide
Service Hints & Tips


Problem Summary;
IBM SSA RAID Adapter for PC Servers - When configuring a RAID 5 Array, ONLY a 128 block Strip size is supported. The Adapter will hang if a Strip size of 32 blocks is used with 9.1 GB drives.

Problem Description:
Although the ONLY supported RAID 5 Array Strip size is 128 blocks, the IBM SSA RAID Adapter for PC Servers Configuration Utility will improperly allow the user to modify the Strip size from 32 - 128 blocks. When configuring a RAID 5 array using 9.1 GB drives and a Strip size of 32 blocks, the Adapter will no longer respond and in most cases the Operating System will hang and require a re-boot. The problem occurs on all 3 supported platforms - OS2 Warp Server, Windows NT 3.51 / 4.0, and Novell Netware 4.1 using 1800 level firmware / Configuration Utility.

Additional physical indications are that the entire SSA Loop will appear to be open - The second drive LED (Drive Ready LED) will flash on both the first and last drive of the installed configuration.

Drive Enclosure
Recovery Method:

1. Power off the SSA enclosure (3527 / 7133) which contains the drives selected when attempting to build the RAID 5 Array.

Note:
This procedure assumes that all of the members of the associated RAID 5 array are located adjacent to each other. If the associated RAID 5 array members (disk drives) are not located adjacent to each other, physically re-arrange them now.

2. Reboot the Server

3. Once the Operating system is up and running, unlatch the drives selected when the RAID 5 Array build was attempted, then power on the associated drive enclosure. Allow approximately 2 minutes for any remaining drives (not disconnected) to sequence up and come on-line.

* IMPORTANT:
The following step will need to be repeated once for each drive of the RAID 5 array. For example, if a 4+1 Array build was attempted, the following step would be repeated 5 times.

4. Reconnect 1 of the drives unlatched during the prior step and allow approximately 1 minute for the drive to sequence up and come on-line.

5. Bring up the SSA RAID Adapter Configuration Utility
- Select SSA ADAPTER LIST - press enter twice
- Select RAID 5 ARRAYS - press enter
- If the name of the failed RAID 5 Array build attempt appears, DELETE the Array. However, NO RESOURCES or prior successful arrays may be indicated. ONLY DELETE THE FAILED RAID 5 ARRAY.
- ESC to the prior menu
- Repeat steps 4 and 5 for each drive of the RAID 5 array which failed during the build attempt.

The attached SSA drive enclosure should no longer indicate an open loop condition and be operational.

The resolution for this problem will require a modification to the SSA Configuration Utility which will no longer allow the user to modify the Strip size when building a RAID 5 array and will be available in a future Driver release (Both the Drivers and Configuration Utilities reside on the Driver diskette of the associated platform utilized).

Work Around Solution:
When building a RAID 5 Array, DO NOT alter the Strip size field and use the default which is 128 blocks.
Document ID:  MCGN-3GVPAW
Last Modified:  2000-07-10
Copyright 2000 IBM Corporation
 HelpCenter Phone List

Worldwide Support
Privacy | Legal | Contact