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Command Control Interface (CCI) is currently not able to specify (or know) the feature of Quick Restore. The type of restore operation run depends on the System Option Mode setting. System Option Mode 80 is used to turn off Quick Restore. System Option Mode 80 is disabled by default on all SE99XX arrays. When Mode 80 is disabled this enables the Quick Restore function on all "pairresync -restore" operations run from CCI. When the Quick Restore Operation is run this causes the volume maps to be swapped from P-Vol to S-Vol, without copying any data. This causes the P-Vol and S-Vol to have the appearance that they physically swapped places. The example below demonstrates the before and after configuration for Parity Group 1-1 on the given array where the pairresync -restore operation was run with Mode 80 disabled:

BEFORE: LDEV Information

Group LDEV Raid      Emulation      Capacity  CVS DCR
1-1   0-00 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-01 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-02 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-03 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-04 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-05 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-06 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-07 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-08 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-09 Raid-1 (2D+2D) Open-E    14.57GB   No  No

AFTER: LDEV Information

Group LDEV Raid      Emulation      Capacity  CVS DCR
1-1   0-03 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-04 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-05 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-06 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-07 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-08 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   0-09 Raid-1 (2D+2D) Open-E    14.57GB   No  No
1-1   3:00 Raid-5 (6D+2P) Open-E    14.57GB   No  No
1-1   3:01 Raid-5 (6D+2P) Open-E    14.57GB   No  No
1-1   3:05 Raid-5 (6D+2P) Open-E    14.57GB   No  No

Note that LDEVs 0:00, 0:01, and 0:02 have been replaced by LDEVs 3:00, 3:01, and 3:05 in Parity Group 1-1. In this particular case the customer could experience severe performance problems given that part of their production database is now running on Raid-5 (6D+2P) as opposed to Raid-1 (2D+2D). There would be no way to determine the exact cause of the performance problem without careful examination of the entire array configuration.

To verify if a particular SE99XX unit may be impacted by this issue, please review the array configuration data via Hitrack and ensure that all LDEVs appear to be in the correct Parity Group.  Attached is the URL: http://se9900.emea.sun.com/se9900hitrack/

If the LDEVs are swapped you must run a "pairresync -restore" with Mode 80 disabled (Quick Restore Enabled) to swap the volume maps and return the P-Vol and S-Vol back to the proper location.

To prevent this from happening at customer sites it necessary to enable System Option Mode 80 on all SE99XX arrays to prevent the misuse of the Quick Restore function and lower the risk of negatively impacting the customers production data.

This problem has recently impacted a number of very large Sun customers and severely impacted their production applications. In the case where P-Vol data resides on higher performing Disks than the S-Vol data it can cause significant performance degradation. In the most recent occurrence of this issue the customer had P-Vol data residing on 72GB 15K RPM HDDs in a Raid-1 (2D+2D) Parity Group. The S-Vol data resided on 300GB 10K RPM HDDs in a Raid-5 (6D+2P) Parity Group. The performance difference between these two HDD's and the Raid-1 (2D+2D) vs. Raid-5 (6D+2P) were enough to severely impact the customer's production environment. Only after reviewing performance data was PTS able to determine that certain parity groups showed 100% utilization, and upon further review that the production data was fully on the 300GB 10K RPM HDDs in the Raid-5 (6D+2P) Parity Groups. Running the "pairresync -restore" swapped the production data back to the 72GB 15K RPM HDDs in the Raid-1 (2D+2D) Parity Groups.

Please refer to the Hitachi Command Control Interface (CCI) User and Reference Guide and the ShadowImage User's Guide for more details:

http://pts-storage.west/products/T99x0/documentation.html

• Manual: Hitachi Command Control Interface (CCI) User and Reference Guide and the ShadowImage User’s Guide
• URL: http://se9900.emea.sun.com/se9900hitrack
  http://pts-storage.west/products/T99x0/documentation.html

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