Microsoft SQL Server Always On availability group performance metrics

Gain deeper visibility into the key metrics of your Microsoft SQL Server Always on Availability Group—including Active Hadr Threads, Replica information, Log Compression Cache Hits, Failover alerts, Synchronization health, Database state, and much more—all from a single, comprehensive console.

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Supported metrics

Metric	Description	Unit
Summary
Availability	Indicates the availability of the availability group.	Percentage
Primary Instance	The primary instance of the availability group.	Text
No. of Replicas	The total number of replicas.	Count
No. of Databases	The total number of databases.	Count
Cluster Details
Availability Group Name	The name of the Always On Availability Group.	Text
Windows Server Failover Cluster	The name of the Windows Server Failover Cluster associated with the availability group.	Text
Cluster Type	The deployment type of the cluster (for example, WSFC, External).	Text
IP Addresses	The IP addresses are configured for the availability group listener.	Text
Port	The port is used for client connections to the availability group.	Number
Automated Backup Preference	The replica backup preference configuration (for example, Primary, Secondary only, Prefer Secondary).	Text
Cluster Health
State	The operational state of the availability group. Possible values include: ONLINE OFFLINE ONLINE_PENDING FAILED	Text
Primary Replica	The name of the current primary replica for the availability group.	Text
Primary Recovery Health	The recovery health status of the primary replica. Possible values include: ONLINE_IN_PROGRESS ONLINE NULL	Text
Secondary Recovery Health	The recovery health status of secondary replicas. Possible values for Secondary Recovery Health: ONLINE_IN_PROGRESS ONLINE NULL Note: On the primary replica, the secondary_recovery_health column is NULL.	Text
DNS Name	The DNS name assigned to the availability group listener.	Text
Replicas	The list of replicas in the availability group.
Replica	The name of an individual availability replica.	Text
Role	The current role of the replica (for example, Primary, Secondary) Possible values: Primary, Secondary, Resolving	Text
Synchronization Health	Roll up of the synchronization health status across all availability replicas. Possible values: Healthy, Partially Healthy, Not Healthy, Unknown	Text
Availability Mode	The description of the Availability Mode of the Replica. Possible values: Synchronous Commit, Asynchronous Commit	Text
Failover Mode	The description of the Failover Mode of the Replica. Possible values include: MANUAL AUTOMATIC	Text
Hadr Threads	The number of active Hadr threads used by the availability group.	Count
Database Details
Database Name	The name of a database that belongs to the availability group.	Text
Replica Server Name	The server name of the instance hosting this replica.	Text
Synchronization Health	Health state of a database on the availability replica. Possible values: Healthy, Partially Healthy, Not Healthy, Unknown	Text
Synchronization State	Description of the data movement state of the database. Possible values: Synchronized, Synchronizing, Suspended, Not Synchronizing, Initializing	Text
Database State	Description of the database state of the availability replica. Possible values: Online, Restoring, Recovering, Recovery Pending, Suspect, Offline	Text
Suspended	Indicates if the database is suspended or not.	Text
Reason	Reason for the database suspension.	Text
Failover Cluster	Whether the secondary database is synchronized with the corresponding primary.	Text
Database Joined State	Whether the database is joined to the availability group.	Text

Replicas
Replica	The name of the availability replica.	Text
Resent Messages	The number of messages being re-sent in the last second.	Count per Second
Flow Control Time(ms/sec)	The time duration that messages waited due to flow control in the last second.	Milliseconds per Second
Flow Control/sec	The number of flow control operations initiated in the last second.	Count per Second
Bytes Sent	The total number of bytes sent to other replicas.	Bytes
Bytes sent to Replica/sec	The number of bytes sent to a secondary replica per second.	Bytes per Second
Bytes Sent to Transport/sec	The number of bytes sent to the transport layer per second.	Bytes per Second
Bytes Received	The total number of bytes received from other replicas.	Bytes
Receives from Replica/sec	The number of bytes received per second from the availability replica.	Bytes per Second
Sends to Replica/sec	The number of bytes sent per second to the availability replica.	Bytes per Second

Databases
Database Name	The name of a database that belongs to the availability group.	Text
Replica Server Name	The name of the SQL Server hosting this replica.	Text
Database Flow Control Delay	The time duration for which database operations were delayed due to flow control.	Microseconds
Database Flow Control per Second	The number of times database flow control was triggered per second.	Count per Second
File Bytes Received /sec	The rate at which bytes are received from the primary replica for database file synchronization.	Bytes per Second
Group Commit Time	The time taken for a group commit operation on the replica.	Microseconds
Group Commit Time/sec	The number of group commit operations per second.	Count per Second
Mirrored Write Transactions/sec	The number of write transactions mirrored to the secondary per second.	Count per Second
Recovery Queue	The amount of log data in the recovery queue awaiting processing.	Kilobytes
Redo Blocked/sec	The number of times per second redo operations were blocked.	Count per Second
Redo Bytes Remaining	The amount of log data left to be redone on the secondary replica.	Kilobytes
Redone Bytes/sec	The rate at which bytes are redone on the replica.	Bytes per Second
Redones/sec	The number of redo operations occurring per second.	Count per Second
Transaction Delay	The time delay between the commit of a transaction on the primary and its hardened copy on the secondary.	Milliseconds

Log Transactions
Database Name	The name of a database that belongs to the availability group.	Text
Replica Server Name	The server name of the SQL Server hosting this replica.	Text
Log Apply Pending Queue	The number of log blocks received but not yet applied on the replica.	Count
Log Apply Ready Queue	The number of log blocks that are ready to be applied on the replica.	Count
Log Bytes Compressed/sec	The number of log bytes compressed per second before being sent to the secondary replica.	Bytes per Second
Log Bytes Decompressed/sec	The number of log bytes decompressed per second on the secondary replica.	Bytes per Second
Log Bytes Received/sec	The number of log bytes received per second from the primary replica.	Bytes per Second
Log Compression Cache Hits/sec	The number of times per second the compression cache was used for log blocks.	Count per Second
Log Compression Cache Misses/sec	The number of times per second the compression cache was missed during log compression.	Count per Second
Log Compressions/sec	The number of log compressions happening per second.	Count per Second
Log Decompressions/sec	The number of log decompressions happening per second.	Count per Second

Replicas – Summary (Replication details)

Replica Server Name	The server name of the SQL Server hosting this replica.	Text
Replication Role	Indicates the role of the replica—primary or secondary.	Text
Endpoint URL	The URL used by the availability replica for data transmission.	Text
Availability Mode	Specifies whether the replica operates in synchronous or asynchronous mode. Possible values: Synchronous Commit, Asynchronous Commit	Text
Failover Mode	Indicates whether failover is automatic or manual.	Text
Primary Role Allow Connections	States whether the primary replica allows connections.	Text
Secondary Role Allow Connections	States whether the secondary replica allows read-only connections.	Text
Creation Time	The timestamp of when the availability replica was created.	Text
Modified Time	The timestamp of the last configuration modification to the replica.	Text
Cluster Health	Overall health status of the WSFC (Windows Server Failover Cluster) hosting the replica.	Text
Operational State	The current operating state of the replica (for example, online, offline).	Text
Connection State	Indicates the connectivity status between replicas.	Text
Recovery Health	Indicates the health of the replica’s recovery process.	Text
Synchronization Health	Reflects the combination of the synchronization state of databases on the replica and the configured availability mode. Possible values: Healthy, Partially Healthy, Not Healthy, Unknown	Text
Seeding Mode	Mode used for automatic seeding of databases (manual or automatic).	Text
Last Connect Error	The last error message encountered when trying to connect to the replica.	Text
Last Connect Error Number	The numeric code of the last connection error.	Count
Last Connect Error Timestamp	The time when the last connection error occurred.	Text
Resent Messages/sec	The number of messages re-sent per second due to dropped connections or errors.	Count per Second

Replicas – Performance metrics

Replica	The name of the replica.	Text
Resent Messages/sec	The number of messages re-sent per second from this replica.	Count per Second
Flow Control Time (ms/sec)	The time messages waited in flow control during the last second.	Milliseconds
Flow Control/sec	The number of flow control initiations per second.	Count per Second
Bytes Sent	The total number of bytes sent from this replica.	Bytes
Bytes sent to Replica/sec	The rate at which bytes are sent from this replica to another per second.	Bytes per Second
Bytes Sent to Transport/sec	The rate at which bytes are sent from the replica to the transport layer per second.	Bytes per Second
Bytes Received	The total number of bytes received by this replica.	Bytes
Receives from Replica/sec	The rate at which this replica receives bytes from another replica per second.	Bytes per Second
Sends to Replica/sec	The rate at which this replica sends bytes to another replica per second.	Bytes per Second

Databases – Performance metrics

Database Name	The name of a database that belongs to the availability group.	Text
Database Flow Control Delay	Time delay introduced by flow-control throttling when synchronizing database transactions	Microseconds
Database Flow Control per Second	Number of flow-control events triggered at the database level each second.	Count per Second
File Bytes Received /sec	Rate at which database file bytes are received from the primary replica.	Bytes per Second
Group Commit Time	Time taken for a group-commit operation on the secondary replica.	Microseconds
Group Commit Time /sec	Number of group-commit operations performed per second.	Count per Second
Mirrored Write Transactions /sec	Number of write transactions mirrored to the secondary per second.	Count per Second
Recovery Queue	Amount of log data (in kilobytes) queued for recovery processing.	Kilobytes
Redo Blocked /sec	Number of times per second that redo operations were blocked.	Count per Second
Redo Bytes Remaining	Amount of log data still pending to be redone on the secondary.	Kilobytes
Redone Bytes /sec	Rate at which bytes are redone on the secondary replica.	Bytes per Second
Redones /sec	Number of redo operations occurring per second.	Count per Second
Transaction Delay	Time difference between commit on primary and hardened copy on secondary.	Milliseconds
Log Apply Queue	Number of log blocks waiting in queue to be applied.	Count
Log Compression Cache	Number of log blocks currently stored in the compression cache.	Count
Log Compression Cache Misses /sec	Number of times per second that the log compression cache did not contain the block needed.	Count per Second
Log Compressions	Total number of log compression operations performed.	Count
Log Bytes Compression	Total bytes processed through log compression.	Bytes

Databases – Status metrics

Database Name	The name of a database that belongs to the availability group.	Text
Replica Server Name	The server name hosting this database replica.	Text
Synchronization Health	Reflects the combined state of the database’s synchronization and the configured availability mode of its replica. Possible values: Healthy, Partially Healthy, Not Healthy, Unknown	Text
Synchronization State	Describes the current data-movement state of the database. Possible values: Synchronized, Synchronizing, Suspended, Not Synchronizing, Initializing
Database State	Indicates the operational status of the database on its replica (for example, Online, Restoring, Recovery Pending).	Text
Suspended	Whether data movement for this database is currently suspended.	Text
Reason	If suspended, provides the reason why the database’s data movement was halted.	Text
Failover Cluster	Indicates if the secondary database remains in sync with the primary as part of the failover cluster.	Text
Database Joined State	Shows whether the database has been successfully joined to the availability group.	Text

Microsoft SQL Server Always On availability group performance metrics

Supported metrics

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