Reference Guide

five minutes when the other DR Series system operations are idle. For more information, see About Data Check and
Continuous Data Verification Scans.
Continuous Data Verification Scans
Data Check performs a data verification scan, also known as a blockmap scan, which cycles every two hours through all
of the objects in the data store. Data integrity verification is done by recalculating the hash values for the underlying
data, and comparing these to the stored hash values using an additional checksum process. Any unexpected data
inconsistencies are reported using the DR Series system alerts process.
For more information, see About Data Check and Priority Write Verify Scans.
Data Check CLI Commands
These DR Series system CLI commands allow you to perform the following Data Check-related scans and display
current Data Check status. There are two sets of Data Check related DR Series system CLI commands: system --
datacheck and stats --datacheck.
system --datacheck Commands
• Display the current Data Check state (enabled/disabled status for namespace, blockmap, or all). For more
information, see system --datacheck.
• Enable Data Check scans (namespace, blockmap, or all). For more information, see system --datacheck [--enable
<all | namespace | blockmap>].
• Disable Data Check scans (for namespace, blockmap, or all). For more information, see system --datacheck [--
disable <all | namespace | blockmap>].
• Set the percentage of available system resources to use for Data Check scans. For more information, see system --
datacheck [--throttle <1-100>].
• Display the list of Data Check help-related options that can be used as a reference when using the CLI. For more
information, see system --help datacheck.
stats --datacheck Commands
• Display the variety of Data Check statistics collected by the DR4000 system. For more information, see stats --
datacheck.
• Reset the Data Check statistics in the DR4000 system. For more information, see stats --reset --datacheck.
• Display the list of Data Check-related options that can be used as a reference when using the DR Series system CLI.
For more information, see stats --help datacheck.
Data Check Options
Data Check performs data integrity checks that detect potential silent data inconsistencies that can affect the system
disks or disk subsystems, and protect user data. Data Check provides the following options that can be set for DR Series
system data scan operations:
• Namespace (system --datacheck --enable namespace).
• Blockmap (system --datacheck --enable blockmap).
• All (system --datacheck --enable all); this is the default setting where both namespace and blockmap are enabled.
Data Check: Namespace Scan Option
The namespace scan option focuses on file attributes such as file size, file name, permissions, and last time modified.
Data integrity verification is done using a checksum process. You can choose to enable or disable the Data Check
namespace scan in the DR Series system based on the command setting you select.
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