Get-DbaIoLatency

Synopsis

Retrieves I/O latency metrics for all database files to identify storage performance bottlenecks

Description

Queries sys.dm_io_virtual_file_stats to collect detailed I/O performance statistics for every database file on the SQL Server instance. Returns calculated latency metrics including read latency, write latency, and overall latency in milliseconds, plus throughput statistics like average bytes per read and write operation. Essential for diagnosing slow database performance caused by storage bottlenecks, helping you identify which specific database files are experiencing high I/O wait times. Based on Paul Randal’s SQL Server performance tuning methodology.

Reference: https://www.sqlskills.com/blogs/paul/how-to-examine-io-subsystem-latencies-from-within-sql-server/
https://www.sqlskills.com/blogs/paul/capturing-io-latencies-period-time/

Syntax

Get-DbaIoLatency
    [-SqlInstance] <DbaInstanceParameter[]>
    [[-SqlCredential] <PSCredential>]
    [-EnableException]
    [<CommonParameters>]

Examples

Example: 1

PS C:\> Get-DbaIoLatency -SqlInstance sql2008, sqlserver2012

Get IO subsystem latency statistics for servers sql2008 and sqlserver2012.

Example: 2

PS C:\> $output = Get-DbaIoLatency -SqlInstance sql2008 | Select-Object * | ConvertTo-DbaDataTable

Collects all IO subsystem latency statistics on server sql2008 into a Data Table.

Example: 3

PS C:\> 'sql2008','sqlserver2012' | Get-DbaIoLatency

Get IO subsystem latency statistics for servers sql2008 and sqlserver2012 via pipline

Example: 4

PS C:\> $cred = Get-Credential sqladmin
PS C:\> Get-DbaIoLatency -SqlInstance sql2008 -SqlCredential $cred

Connects using sqladmin credential and returns IO subsystem latency statistics from sql2008

Required Parameters

-SqlInstance

The SQL Server instance. Server version must be SQL Server version 2008 or higher.

Optional Parameters

-SqlCredential

Login to the target instance using alternative credentials. Accepts PowerShell credentials (Get-Credential).
Windows Authentication, SQL Server Authentication, Active Directory - Password, and Active Directory - Integrated are all supported.
For MFA support, please use Connect-DbaInstance.

-EnableException

By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
This avoids overwhelming you with “sea of red” exceptions, but is inconvenient because it basically disables advanced scripting.
Using this switch turns this “nice by default” feature off and enables you to catch exceptions with your own try/catch.