Dell UCPM-800 manual Smart Feature, Patrol Read

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•Support for controller failover in systems with Fault Tolerant Shared PERC 8 card configuration. The following sections describe some methods to achieve fault tolerance.

The SMART Feature

The SMART feature monitors certain physical aspects of all motors, heads, and physical disk electronics to help detect predictable physical disk failures. Data on SMART-compliant physical disks can be monitored to identify changes in values and determine whether the values are within threshold limits. Many mechanical and electrical failures display some degradation in performance before failure.

A SMART failure is also referred to as predicted failure. There are numerous factors that are predicted physical disk failures, such as a bearing failure, a broken read/write head, and changes in spin-up rate. In addition, there are factors related to read/write surface failure, such as seek error rate and excessive bad sectors.

NOTE: For detailed information on SCSI interface specifications, see t10.org and for detailed information on SATA interface specifications, see t13.org.

Patrol Read

The Patrol Read feature is designed as a preventive measure to ensure physical disk health and data integrity. Patrol Read scans for and resolves potential problems on configured physical disks. The Dell Chassis Management Controller (CMC) can be used to start and control the features of Patrol Read.

The following is an overview of Patrol Read:

•Patrol Read runs on all disks on the controller that are configured as part of a virtual disk, including hot spares.

•Patrol Read does not run on physical disks that are not part of a virtual disk or are in Ready state.

•Patrol Read adjusts the amount of controller resources dedicated to Patrol Read operations based on outstanding disk I/O. For example, if the system is busy processing I/O operation, then Patrol Read uses fewer resources to allow the I/O to take a higher priority.

•Patrol Read does not run on disks involved in any of the following operations:

–Rebuild

–Replace Member

–Full or Background Initialization

–Consistency Check (CC)

NOTE: By default, Patrol Read automatically runs every seven days on configured SAS hard drives. Patrol Read is not necessary on SSD and is disabled by default.

NOTE: In the event of a controller failover in systems with Fault Tolerant Shared PERC 8 card configuration, Patrol Read does not continue on the active controller. You must start Patrol Read again through CMC. If you do not start Patrol Read, it automatically starts on the active controller within seven days of the failover.

For more information on Patrol Read, see the Dell Chassis Management Controller for PowerEdge VRTX Online Help.

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Contents User’s Guide Page Contents Driver Installation Deploying The Shared Perc 8 CardGetting help Configurations of the Shared Perc 8 card About The Shared Perc 8 CardSpecifications of a Shared Perc 8 card Storage Subsystem Compatibility Matrix at dell.comPage Supported Operating Systems Best Practices For Shared PercRelated Documentation Locating your system Service Tag Contacting DellDocumentation Feedback Consistency Checks Shared Perc 8 Card FeaturesPhysical Disk Power Management Virtual Disk InitializationFull Initialization Of Virtual Disks Physical Disk RoamingBackground Initialization Of Virtual Disks Fast Initialization Of Virtual DisksUsing Physical Disk Roaming FastPathVirtual Disk Migration Virtual Disk Cache Policies Migrating Virtual Disks If The Target System Is Turned OffMigrating Virtual Disks If The Target System Is Turned On Conditions Under Which Write-Back Is Employed Virtual Disk Write Cache PoliciesWrite-Back Write-throughConditions under which write-through is employed Fault TolerancePhysical Disk Write Cache Policy Virtual Disk Read Cache PoliciesSmart Feature Patrol ReadPhysical disk failure detection Physical Disk Hot SwappingShared Perc 8 Card Cache Preservation Battery Transparent Learn Cycle Controller Failover FeatureMultipath Support Configuring Multipath Support In WindowsConfiguring Multipath Support In VMWare Multipath support in LinuxInstalling a New Shared Perc 8 Card Deploying The Shared Perc 8 CardReplacing a Shared Perc 8 Card Prerequisites For Removing The Shared Perc 8 Card Removing The Shared Perc 8 CardRemoving and Installing the Shared Perc 8 Card Installing The Shared Perc 8 Card Post-Installation Tasks For Shared Perc 8 CardFirmware installation or update Updating firmwareDriver Installation Installing Or Updating Windows Drivers For Shared Perc Installing Or Updating Linux Drivers For Shared Perc Installing Or Updating VMware Drivers For Shared PercManagement Applications For Shared Perc 8 Card Troubleshooting Shared Perc 8 Card Boots Into Safe ModeGeneral Issues Degraded State Of Virtual DisksShared Perc 8 Card Not Seen In Device Manager Shared Perc 8 Cards Fail To Function Physical disk issuesUnable to rebuild a fault tolerant virtual disk Physical Disk In Failed StateFatal Error Or Data Corruption Reported Multiple Disks Become InaccessibleRebuilding a Failed Physical Disk Virtual Disk Fails During Rebuild Using a Global Hot Spare Controller cache issuesPhysical disk takes a long time to rebuild Smart Errors Target Disk Fails Auto Replacement Member ErrorsSource Disk Fails General Disk FailsHard-Drive Indicator Patterns Hard-Drive IndicatorsGetting help Documentation feedback
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