functions/Test-DbaLastBackup.ps1

Function Test-DbaLastBackup
{
<#
.SYNOPSIS
Quickly and easily tests the last set of full backups for a server
 
.DESCRIPTION
Restores all or some of the latest backups and performs a DBCC CHECKTABLE
 
1. Gathers information about the last full backups
2. Restores the backps to the Destination with a new name. If no Destination is specified, the originating SqlServer wil be used.
3. The database is restored as "dbatools-testrestore-$databaseName" by default, but you can change dbatools-testrestore to whatever you would like using -Prefix
4. The internal file names are also renamed to prevent conflicts with original database
5. A DBCC CHECKTABLE is then performed
6. And the test database is finally dropped
 
.PARAMETER SqlServer
The SQL Server to connect to. Unlike many of the other commands, you cannot specify more than one server.
 
.PARAMETER Destination
The destination server to use to test the restore. By default, the Destination will be set to the source server
     
If a different Destination server is specified, you must ensure that the database backups are on a shared location
     
.PARAMETER SqlCredential
Allows you to login to servers using alternative credentials
 
$scred = Get-Credential, then pass $scred object to the -SqlCredential parameter
 
Windows Authentication will be used if SqlCredential is not specified
 
.PARAMETER DestinationCredential
Allows you to login to servers using alternative credentials
 
$scred = Get-Credential, then pass $scred object to the -SqlCredential parameter
 
Windows Authentication will be used if SqlCredential is not specified
 
.PARAMETER Databases
The database backups to test. If -Databases is not provided, all database backups will be tested
 
.PARAMETER Exclude
Exclude specific Database backups to test
 
.PARAMETER DataDirectory
The command uses the SQL Server's default data directory for all restores. Use this parameter to specify a different directory for mdfs, ndfs and so on.
 
.PARAMETER LogDirectory
The command uses the SQL Server's default log directory for all restores. Use this parameter to specify a different directory for ldfs.
 
.PARAMETER VerifyOnly
Do not perform the actual restore. Just perform a VERIFYONLY
 
.PARAMETER NoCheck
Skip DBCC CHECKTABLE
 
.PARAMETER NoDrop
Do not drop newly created test database
 
.PARAMETER MaxMB
Do not restore databases larger than MaxMB
 
.PARAMETER Prefix
The database is restored as "dbatools-testrestore-$databaseName" by default. You can change dbatools-testrestore to whatever you would like using this parameter.
     
.PARAMETER WhatIf
Shows what would happen if the command were to run
     
.PARAMETER Confirm
Prompts for confirmation of every step. For example:
 
Are you sure you want to perform this action?
Performing the operation "Restoring model as dbatools-testrestore-model" on target "SQL2016\VNEXT".
[Y] Yes [A] Yes to All [N] No [L] No to All [S] Suspend [?] Help (default is "Y"):
     
.NOTES
Tags: DisasterRecovery, Backup, Restore
dbatools PowerShell module (https://dbatools.io, clemaire@gmail.com)
Copyright (C) 2016 Chrissy LeMaire
 
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
 
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.
 
.LINK
https://dbatools.io/Test-DbaLastBackup
 
.EXAMPLE
Test-DbaLastBackup -SqlServer sql2016
 
Determines the last full backup for ALL databases, attempts to restore all databases (with a different name and file structure), then performs a DBCC CHECKTABLE
 
Once the test is complete, the test restore will be dropped
 
.EXAMPLE
Test-DbaLastBackup -SqlServer sql2016 -Databases master
 
Determines the last full backup for master, attempts to restore it, then performs a DBCC CHECKTABLE
 
.EXAMPLE
Test-DbaLastBackup -SqlServer sql2016 -Databases model, master -VerifyOnly
 
.EXAMPLE
Test-DbaLastBackup -SqlServer sql2016 -NoCheck -NoDrop
 
Skips the DBCC CHECKTABLE check. This can help speed up the tests but makes it less tested. NoDrop means that the test restores will remain on the server.
 
.EXAMPLE
Test-DbaLastBackup -SqlServer sql2016 -DataDirectory E:\bigdrive -LogDirectory L:\bigdrive -MaxMB 10240
 
Restores data and log files to alternative locations and only restores databases that are smaller than 10 GB
     
#>

    [CmdletBinding(SupportsShouldProcess = $true)]
    Param (
        [parameter(Mandatory = $true)]
        [Alias("ServerInstance", "SqlInstance", "Source")]
        [string]$SqlServer,
        [object]$SqlCredential,
        [string]$Destination = $SqlServer,
        [object]$DestinationCredential,
        [string]$DataDirectory,
        [string]$LogDirectory,
        [string]$Prefix = "dbatools-testrestore",
        [switch]$VerifyOnly,
        [switch]$NoCheck,
        [switch]$NoDrop,
        [int]$MaxMB
        
    )
    
    DynamicParam { if ($sqlserver) { return Get-ParamSqlDatabases -SqlServer $sqlserver -SqlCredential $SqlCredential } }
    
    BEGIN
    {
        $databases = $psboundparameters.Databases
        $exclude = $psboundparameters.Exclude
        
        if ($SqlServer -eq $destination)
        {
            $DestinationCredential = $SqlCredential
        }
        
        $sourceserver = Connect-SqlServer -SqlServer $SqlServer -SqlCredential $sqlCredential
        $destserver = Connect-SqlServer -SqlServer $destination -SqlCredential $DestinationCredential
        
        if ($destserver.VersionMajor -lt $sourceserver.VersionMajor)
        {
            Write-Warning "$Destination is a lower version than $Sqlserver. Backups would be incompatible."
            continue
        }
        
        if ($destserver.VersionMajor -eq $sourceserver.VersionMajor -and $destserver.VersionMinor -lt $sourceserver.VersionMinor)
        {
            Write-Warning "$Destination is a lower version than $Sqlserver. Backups would be incompatible."
            continue
        }
        
        if ($SqlServer -ne $destination)
        {
            $sourcerealname = $sourceserver.DomainInstanceName
            $destrealname = $sourceserver.DomainInstanceName
            
            if ($BackupFolder)
            {
                if ($BackupFolder.StartsWith("\\") -eq $false -and $sourcerealname -ne $destrealname)
                {
                    throw "Backup folder must be a network share if the source and destination servers are not the same."
                }
            }
            
        }
        
        $source = $sourceserver.DomainInstanceName
        $destination = $destserver.DomainInstanceName
        
        if ($datadirectory)
        {
            if (!(Test-SqlPath -SqlServer $destserver -Path $datadirectory))
            {
                $serviceaccount = $destserver.ServiceAccount
                Write-Warning "Can't access $datadirectory Please check if $serviceaccount has permissions"
                continue
            }
        }
        else
        {
            $datadirectory = Get-SqlDefaultPaths -SqlServer $destserver -FileType mdf
        }
        
        if ($logdirectory)
        {
            if (!(Test-SqlPath -SqlServer $destserver -Path $logdirectory))
            {
                $serviceaccount = $destserver.ServiceAccount
                Write-Warning "$Destination can't access its local directory $logdirectory. Please check if $serviceaccount has permissions"
                continue
            }
        }
        else
        {
            $logdirectory = Get-SqlDefaultPaths -SqlServer $destserver -FileType ldf
        }
        
        if ($databases.count -eq 0)
        {
            $databases = $sourceserver.databases.Name
        }
    }
    
    PROCESS
    {
        if ($databases -or $exclude)
        {
            $dblist = $databases
            
            if ($exclude)
            {
                $dblist = $dblist | Where-Object $_ -notin $exclude
            }
            
            foreach ($dbname in $dblist)
            {
                if ($dbname -eq 'tempdb') { continue }
                
                $db = $sourceserver.databases[$dbname]
                
                # The db check is needed when the number of databases exceeds 255, then it's no longer autopopulated
                if (!$db)
                {
                    Write-Warning "$dbname does not exist on $source."
                    continue
                }
                
                $lastbackup = Get-DbaBackupHistory -SqlServer $sourceserver -Databases $dbname -LastFull
                
                if ($lastbackup -eq $null)
                {
                    $lastbackup = @{ Path = "Not found" }
                    $fileexists = $false
                    $restoreresult = "Skipped"
                    $dbccresult = "Skipped"
                }
                elseif ($source -ne $destination -and $lastbackup[0].Path.StartsWith('\\') -eq $false)
                {
                    $fileexists = "Skipped"
                    $restoreresult = "Restore not located on shared location"
                    $dbccresult = "Skipped"
                }
                elseif ((Test-SqlPath -SqlServer $destserver -Path $lastbackup[0].Path) -eq $false)
                {
                    $fileexists = $false
                    $restoreresult = "Skipped"
                    $dbccresult = "Skipped"
                }
                else
                {
                    $fileexists = $true
                    $restorelist = Read-DbaBackupHeader -SqlServer $destserver -Path $lastbackup[0].Path
                    $mb = $restorelist.BackupSizeMB
                    
                    if ($MaxMB -gt 0 -and $MaxMB -lt $mb)
                    {
                        $restoreresult = "The backup size for $dbname ($mb MB) exceeds the specified maximum size ($MaxMB MB)"
                        $dbccresult = "Skipped"
                    }
                    else
                    {
                        $filelist = $restorelist.Filelist
                        $dbname = $restorelist.DatabaseName
                        $temprestoreinfo = @()
                        
                        foreach ($file in $filelist)
                        {
                            if ($file.Type -eq 'L')
                            {
                                $dir = $logdirectory
                            }
                            else
                            {
                                $dir = $datadirectory
                            }
                            
                            $fn = Split-Path $file.PhysicalName -Leaf
                            $temprestoreinfo += [pscustomobject]@{
                                Logical = $file.LogicalName
                                Physical = "$dir\$prefix-$fn"
                            }
                        }
                        
                        $ogdbname = $dbname
                        $dbname = "$prefix-$dbname"
                        
                        $destdb = $destserver.databases[$dbname]
                        
                        if ($destdb)
                        {
                            Write-Warning "$dbname already exists on $destination - skipping"
                            continue
                        }
                        
                        if ($Pscmdlet.ShouldProcess($destination, "Restoring $ogdbname as $dbname"))
                        {
                            $restoreresult = Restore-Database -SqlServer $destserver -DbName $dbname -backupfile $lastbackup.path -filestructure $temprestoreinfo -VerifyOnly:$VerifyOnly
                        }
                        
                        if (!$NoCheck -and !$VerifyOnly)
                        {
                            # shouldprocess is taken care of in Start-DbccCheck
                            if ($ogdbname -eq "master")
                            {
                                $dbccresult = "DBCC CHECKTABLE skipped for restored master ($dbname) database"
                            }
                            else
                            {
                                $dbccresult = Start-DbccCheck -Server $destserver -DbName $dbname -Table 3>$null
                            }
                        }
                        
                        if ($VerifyOnly) { $dbccresult = "Skipped" }
                        
                        if (!$NoDrop -and $restoreresult -eq "Success")
                        {
                            if ($Pscmdlet.ShouldProcess($dbname, "Dropping Database $dbname on $destination"))
                            {
                                ## Drop the database
                                try
                                {
                                    $removeresult = Remove-SqlDatabase -SqlServer $destserver -DbName $dbname
                                    Write-Verbose "Dropped $dbname Database on $destination"
                                }
                                catch
                                {
                                    Write-Warning "Failed to Drop database $dbname on $destination"
                                    Write-Exception $_
                                    continue
                                }
                            }
                        }
                        
                        if ($destserver.Databases[$dbname] -ne $null -and !$NoDrop)
                        {
                            Write-Warning "$dbname was not dropped"
                        }
                    }
                }
                
                if ($Pscmdlet.ShouldProcess("console", "Showing results"))
                {
                    [pscustomobject]@{
                        SourceServer = $source
                        TestServer = $destination
                        Database = $db.name
                        FileExists = $fileexists
                        RestoreResult = $restoreresult
                        DbccResult = $dbccresult
                        SizeMB = ($lastbackup.TotalSizeMB | Measure-Object -Sum).Sum
                        BackupTaken = $lastbackup.Start
                        BackupFiles = $lastbackup.Path
                    }
                }
            }
        }
    }
    
    END
    {
        $sourceserver.ConnectionContext.Disconnect()
        $destserver.ConnectionContext.Disconnect()
    }
}