internal/Test-DbaLsnChain.ps1
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function Test-DbaLsnChain { <# .SYNOPSIS Checks that a filtered array from Get-FilteredRestore contains a restorabel chain of LSNs .DESCRIPTION .PARAMETER FilterdRestoreFiles .PARAMETER RestoreTime Returns fewer columns for an easy overview .NOTES 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/>. .EXAMPLE Test-DbaLsnChain -FilteredRestoreFiles $FilteredFiles Checks that the Restore chain in $FilteredFiles is complete and can be fully restored .EXAMPLE Test-DbaLsnChain -FilteredRestoreFiles $FilteredFiles -RestoreTime '23/12/2016 06:55' Checks that the Restore chain in $FilteredFiles is complete and can be fully restored to the Point In Time '23/12/2016 06:55' #> [CmdletBinding()] Param ( [parameter(Mandatory = $true)] [object[]]$FilteredRestoreFiles, [DateTime]$RestoreTime = (Get-Date).addyears(1) ) #Need to anchor with full backup: $FunctionName = "Test-DbaLsnChain" $FullDBAnchor = $FilteredRestoreFiles | Where-Object {$_.BackupTypeDescription -eq 'Database'} if (($FullDBAnchor | Measure-Object).count -ne 1) { Write-Error "$FunctionName - More than 1 full backup, or less than 1, neither supported" return $false break; } #Check all the backups relate to the full backup #Via RecoveryForkID: if (($FilteredRestoreFiles | Where-Object {$_.RecoveryForkID -ne $FullDBAnchor.RecoveryForkID}).count -gt 0) { Write-Error "$FunctionName - Multiple RecoveryForkIDs found, not supported" return $false break } #Via LSN chain: $BackupWrongLSN = $FilteredRestoreFiles | Where-Object {$_.DatabaseBackupLSN -ne $FullDBAnchor.CheckPointLSN} #Should be 0 in there, if not, lets check that they're from during the full backup if ($BackupWrongLSN.count -gt 0 ) { if (($BackupWrongLSN | Where-Object {$_.LastLSN -lt $FullDBAnchor.LastSN}).count -gt 0) { Write-Error "$FunctionName - We have non matching LSNs - not supported" return $false break; } } $DiffAnchor = $FilteredRestoreFiles | Where-Object {$_.BackupTypeDescription -eq 'Database Differential'} #Check for no more than a single Differential backup if (($DiffAnchor | Measure-Object).count -gt 1) { Write-Error "$FunctionName - More than 1 differential backup, not supported" return $false break; } elseif (($DiffAnchor | Measure-Object).count -gt 1) { $TlogAnchor = $DiffAnchor } else { $TlogAnchor = $FullDBAnchor } #Check T-log LSNs form a chain. $TranLogBackups = $FilteredRestoreFiles | Where-Object {$_.BackupTypeDescription -eq 'Transaction Log' -and $_.DatabaseBackupLSN -eq $FullDBAnchor.CheckPointLSN} | Sort-Object -Propert LastLSN for ($i=0; $i -lt ($TranLogBackups.count)-1) { if ($i -eq 0) { if ($TranLogBackups[$i].FirstLSN -gt $TlogAnchor.LastLSN) { Write-Error "$FunctionName - Break in LSN Chain between $($TlogAnchor.BackupPath) and $($TranLogBackups[($i)].BackupPath) " return $false break } }else { if ($TranLogBackups[($i-1)].LastLsn -ne $TranLogBackups[($i)].FirstLSN) { Write-Error "$FunctionName - Break in transaction log between $($TranLogBackups[($i-1)].BackupPath) and $($TranLogBackups[($i)].BackupPath) " return $false break } } $i++ } return $true } |