When background parity initialization does not complete on cluster-shared volumes, the following warning messages are displayed:
Array Configuration Utility (ACU) Popup Warning Message
Background parity initialization is currently queued or in progress on Compaq RA4000/4100 Controller in RAID Array BOX7 on the following logical drives:
Logical Drive x
This is a normal operation that is necessary to initialize logical drives that have a fault tolerance with parity. If background parity initialization is queued, it will start when I/O is performed on the drives. When background parity initialization completes, the performance of the logical drives will improve.
ACU (XE) Controller Status Message
Background parity initialization is currently queued or in progress on logical drive X ( RAID 5 in array B). If background parity initialization is queued, it will start when I/O is performed on the drive. When background parity initialization completes, the performance of the logical drive will improve.
When background parity initialization does not complete on other (non-cluster-shared) volumes, the following warning messages are displayed along with above warning messages.
POST Error Messages
1729-Slot X Drive Array - Disk Consistency Initialization In Progress RAID 4/5 performance may be lower until Auto Reliability Monitoring has completed Automatic Background Parity Consistency Initialization
OR
1729 - Slot x Drive Array - Disk performance Optimization Scan In Progress- RAID 4/5/ADG performance may be higher after completion.
System Event Log Message
Source: Server Agents
Type: Warning
Event Id: 1123 message
Description: "Warning: Compaq System Information Agent: Compaq Health: POST Errors Detected. One or more POST errors detected during server setup [SNMP Trap: 6027 in CPQHLTH.MIB]."
Background parity initialization is a normal operation that is necessary to initialize logical drives that have a fault tolerance with parity. If background parity initialization is queued, it will start when I/O is performed on the drives. When background parity initialization completes, the performance of the logical drives will improve.
HP Smart Array Controllers allow parity initialization for RAID 4, RAID 5 or ADG to be completed as a background process, thus avoiding the significant delays required by controllers that do not support this feature. The warning messages indicate that this process has not been completed.
IMPORTANT: NO DATA IS AT RISK. The warning messages indicate only that the Background Parity Initialization process has not been completed. All data that has been written during this process is fully protected against a single-drive failure for RAID 4 and RAID 5, and up to two drive failures for ADG RAID.
To maximize performance during this process, the Smart Array Controller starts background parity initialization, by default, whenever there is no I/O activity for 15 seconds and stops when there are any I/O requests made by the operating system or any application. Since this process is completed as a background task, if there are any applications or services installed which result in constant disk I/O or periodic access more frequent than this 15-second limit, the constant I/O will interfere with this process.
Also, as a precautionary measure, when new logical drives are being configured, the controller will not begin this initialization process until the operating system writes to the logical drive. This will occur when the disk is formatted or a disk signature is created. In addition, these warning messages will continue to occur until all logical drives that were created in ACU are written to or formatted. For example, if five logical drives are created and only four are subsequently formatted, the warning messages will continue to be displayed.
Windows 2000 Microsoft Cluster Services (MSCS) prevents background parity initialization from completing as a background task. Microsoft has changed the disk arbitration algorithm in Windows 2000 cluster services to provide better support for a multi-node cluster environment. This algorithm requires periodic writes to each cluster volume or disk resource every three seconds. This process is cumulative, so a controller with three (or more) cluster volumes will be accessed up to the maximum frequency of once per second. Since this will not allow the background parity initialization process to complete, it must be completed before the Cluster Service is loaded.
Note: The status of the parity initialization of any logical drives can be viewed using the Array Configuration Utility (ACU), ACU-XE or the Array Diagnostic Utility (ADU). The quickest method is to launch ACU. If the pop-up warning messages listed above are not displayed, then all logical drives are initialized. When using ACU-XE, check for the Controller Status Message listed above. If the ACU-XE Controller Status Message is not logged for any controller, then all logical drives are initialized.
