Dell UCPB-900 Appendix RAID description, Summary of RAID levels, RAID terminology, Disk striping

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Appendix: RAID description

RAID is a group of independent physical disks that provides high performance by increasing the number of disks used for saving and accessing data.

CAUTION: In the event of a physical disk failure, a RAID 0 virtual disk fails, resulting in data loss.

A RAID disk subsystem offers the following benefits:

•Improved I/O performance and data availability.

•Improved data throughput because several disks are accessed simultaneously. The physical disk group appears either as a single storage unit or multiple logical units to the host system.

•Improved data storage availability and fault tolerance. Data loss caused by a physical disk failure can be recovered by rebuilding missing data from the remaining physical disks containing data or parity.

Summary of RAID levels

Following is the RAID levels supported by PERC 9 series of cards:

•RAID 0 uses disk striping to provide high data throughput, especially for large files in an environment that requires no data redundancy.

•RAID 1 uses disk mirroring so that data written to one physical disk is simultaneously written to another physical disk. RAID 1 is good for small databases or other applications that require small capacity and complete data redundancy.

•RAID 5 uses disk striping and parity data across all physical disks (distributed parity) to provide high data throughput and data redundancy, especially for small random access.

•RAID 6 is an extension of RAID 5 and uses an additional parity block. RAID 6 uses block-level striping with two parity blocks distributed across all member disks. RAID 6 provides protection against double disk failures, and failures while a single disk is rebuilding. If you are using only one array, deploying RAID 6 is more effective than deploying a hot spare disk.

•RAID 10 is a combination of RAID 0 and RAID 1, uses disk striping across mirrored disks. It provides high data throughput and complete data redundancy.

•RAID 50 is a combination of RAID 0 and RAID 5 where a RAID 0 array is striped across RAID 5 elements. RAID 50 requires at least six disks.

•RAID 60 is a combination of RAID 0 and RAID 6 where a RAID 0 array is striped across RAID 6 elements. RAID 60 requires at least eight disks.

RAID terminology

Disk striping

Disk striping allows you to write data across multiple physical disks instead of just one physical disk. Disk striping involves partitioning each physical disk storage space in stripes of the following sizes: 64 KB, 128

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Contents Dell PowerEdge RAID Controller Perc 9 User’s Guide Page Contents Driver installation Deploying the Perc cardBios Configuration Utility UEFI/HII RAID configuration utility Security key and RAID management100 Appendix RAID description Getting helpFeatures of Perc H330 adapter card OverviewFeatures of Perc H330 mini monolithic card Features of Perc H730 card Features of Perc H730/H730P mini monolithic card Features of Perc H730P adapter card Features of Perc H830 adapter card Supported operating systemsPerc card specifications Perc H330 Perc H730 Perc H730P Perc H830SAS Comprehensive embedded management Management applications for Perc cardsDell OpenManage Storage Management Related documentation Getting started with your Perc card Creating Global Hot Spares Creating Security KeyCreating Global Hot Spares Creating Security Key Creating virtual disks Setting up virtual disks Manage physical disks Creating Global Hot Spares Creating Security Key Page Features Perc 9 personality managementT10 protection information Enabling T10 PISecure firmware update Improved RAID 10 configurationPhysical disk power management 4KB block size disk drivesTypes of virtual disk initialization Configured spin down delayFull initialization Consistency checks Background initializationFast initialization Using disk roaming Configuring FastPath-capable virtual disksDisk roaming FastPathVirtual disk migration Migrating virtual disksVirtual disk read cache policies Virtual disk write cache policiesConditions under which write-back is employed Reconfiguration of virtual disks Or more Yes Removes Redundancy While increasing Capacity Fault tolerance Smart FeaturePatrol Read Using persistent hot spare slotsPhysical disk failure detection Physical disk hot swapping Using replace member and revertible hot sparesController cache preservation Battery Transparent Learn Cycle Non-RAID disks supportSelect OK Deploying the Perc card Removing the Perc 9 adapterBattery cable connector Perc 9 card SAS cables Installing the Perc 9 adapter Removing the Perc 9 mini monolithic controllerReplacing the battery of a H730P mini monolithic card Removing and installing the Perc 9 mini monolithic cardRemoving the battery carrier Installing the Perc 9 mini monolithic controller Removing the batteryRemoving a H730P slim card Replacing the battery of a H730P slim card Removing and installing a H730P slim cardRemoving the battery Installing a H730P slim card Removing the Perc 9 mini blade controllerReplacing the tethered battery of a Perc 9 mini blade card Removing and installing the Perc 9 mini blade controllerRemoving the battery carrier Removing the battery from the battery carrier Installing the battery into the battery carrier Installing the Perc 9 mini blade controller Replacing the battery carrierRemoving the Perc FD33xD Card Replacing the battery of a Perc FD33xD card Removing and installing the Perc FD33xD cardInstalling the Perc FD33xD card Page Creating the device driver media Driver installationDownloading drivers from the Dell support website Windows driver installation Linux driver installation Page Entering the Bios Configuration Utility Bios Configuration UtilityExiting the Configuration Utility Menu navigation controls Setting up virtual disks For more information, see Managing dedicated hot sparesParameters description Bios Configuration Utility menu options Virtual disk managementPage Virtual disk actions Physical disk management PD Mgmt Physical disk actionsRebuild Controller management Ctrl MgmtController management actions Virtual Disk Management Foreign configuration viewCreating virtual disks Selecting virtual disk parameters Initializing virtual disksChecking data consistency Running a data consistency checkPage Break mirror Break mirror in Bios configuration utility Managing preserved cacheManaging dedicated hot spares Deleting virtual disksClearing the configuration Setting LED blinkingPhysical Disk Management Deleting disk groupsRemoving global or dedicated hot spares Creating global hot sparesReplacing an online physical disk Stopping background initialization Restrictions and limitationsPerforming a manual rebuild of an individual physical disk Enabling boot support for a BIOS-enabled controller Enabling boot supportController Management Enabling Bios stop on error Disabling Bios stop on errorEnabling auto import Disabling auto importRestoring factory default settings UEFI/HII RAID configuration utility Entering the Uefi configuration utilityExiting the Uefi configuration utility Navigating to Dell Perc 9 configuration utilityConfiguration management Creating profile based virtual disks Converting physical disks to RAID capable diskConverting physical disks to non-RAID disk Viewing disk group propertiesManaging foreign configurations on a RAID controller Deleting existing configurations on a RAID controllerRestoring factory settings for the controller Saving controller eventsEnabling security for the controller Switching the controller to HBA modeSaving debug log Viewing virtual disk properties Switching the controller to RAID modeViewing physical disks associated with a virtual disk Hardware components management Viewing battery propertiesViewing physical disk properties Viewing physical disks associated with an enclosure Security key and RAID management Security key management in the Bios configuration utilitySecurity key implementation Creating a security key Local Key Management LKMChanging the security key Creating secured virtual disks Deleting a security keySecuring pre-existing virtual disks Page Instant secure erase Troubleshooting Bios configuration utility error messagesDiscovery error message Extra enclosure error messageMissing virtual disks error message Previous configuration of disks removed error messageDirty cache data error message Drive Configuration Changes Error Message Bios disabled error messageAdapter at baseport not responding error message Virtual disks degraded error message Virtual disks offline error messageVirtual disks partially degraded error message Memory or battery problem error message Firmware fault state error messageForeign configuration found error message Foreign configuration not found in ctrl R error messagePrevious configuration cleared or missing error message Invalid SAS topology detected error messageConfigured disks removed or not accessible error message Degraded state of virtual disksMemory errors Security key errorsSecured foreign import errors Preserved Cache StateGeneral Issues Physical disk issuesUnable to rebuild a fault tolerant virtual disk Fatal error or data corruption reportedMultiple disks become inaccessible Physical disk displayed as blockedVirtual disk fails during rebuild using a global hot spare Virtual disk fails rebuild using a dedicated hot spareRebuilding a failed physical disk Physical disk takes a long time to rebuildSmart errors Replace member errorsLinux operating system errors Source disk fails during replace member operationTarget disk fails General disk failsDisk Carrier LED Indicators Uefi error messagesUnable to register Scsi device error message Unhealthy Status of the DriversCorrective Action Appendix RAID description Summary of RAID levelsRAID terminology Disk stripingDisk mirroring Spanned RAID levelsParity data Example of Distributed Parity RAIDLocating your system Service Tag Getting helpContacting Dell Documentation feedback
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