I have updated my backup stored procedure, isp_Backup, as the old version had two issues. It did not exclude database snapshots, which can't be backed up. It also was not checking for the number of CPUs in the registry properly. The CPU check only affects backups when SQL Litespeed is used.

In the next version, I will exclude those databases that are being log shipped by SQL Litespeed as we don't want to interfere with the LSNs. I am already checking for this condition for native backups. I will also add code to perform a full backup when it is performing a differential or transaction log backup and a full backup does not exist. This will be done to avoid backup errors.

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-- OBJECT NAME            : isp_Backup
--
-- AUTHOR               : Tara Kizer
--
-- INPUTS                : @path - location of the backups, default backup directory used if @path is null
--                          @dbType - which database(s) to backup
--                            All, System, User, or dash followed by database name (ex. -Toolbox)
--                          @bkpType - type of backup to perform
--                            Full, TLog, Diff
--                          @retention - number of days to retain backups, -1 to retain all files
--                          @liteSpeed - perform backup using LiteSpeed (Imceda product)
--                            N, Y
--
-- OUTPUTS                : None
--
-- RETURN CODES            : 0-10 (see @error table variable at the end for the messages)
--
-- DEPENDENCIES            : None
--
-- DESCRIPTION            : Performs backups.
--
-- EXAMPLES (optional)  : EXEC isp_Backup @path = 'C:\MSSQL\Backup\', @dbType = 'All', @bkpType = 'Full', @retention = 5, @liteSpeed = 'N'
----------------------------------------------------------------------------------------------------
CREATE PROC [dbo].[isp_Backup]
(@path varchar(100), @dbType sysname = 'All', @bkpType char(4) = 'Full', @retention smallint = 2, @liteSpeed char(1) = 'N')
AS

SET NOCOUNT ON

DECLARE @now char(14)             -- current date in the form of yyyymmddhhmmss
DECLARE @dbName sysname         -- database name that is currently being processed
DECLARE @cmd nvarchar(4000)     -- dynamically created DOS command
DECLARE @result int             -- result of the dir DOS command
DECLARE @rowCnt int             -- @@ROWCOUNT
DECLARE @fileName varchar(200)    -- path and file name of the BAK file
DECLARE @edition int            -- edition of SQL Server (1 - Personal or Desktop Engine; 2 - Standard; 3 - Developer or Enterprise)
DECLARE @rc int                    -- return code
DECLARE @extension char(4)        -- extension for backup file
DECLARE @version char(1)        -- one digit version number, i.e. 8 (2000) or 9 (2005)

-- log shipping tables have been renamed in 2005
SET @version = CONVERT(char(1), SERVERPROPERTY('ProductVersion'))

IF @version NOT IN ('8', '9')
BEGIN
    SET @rc = 1
    GOTO EXIT_ROUTINE
END

-- Enterprise and Developer editions have msdb.dbo.log_shipping* tables, other editions do not
SET @edition = CONVERT(int, SERVERPROPERTY('EngineEdition'))

-- validate input parameters
IF @dbType IS NOT NULL AND @dbType NOT IN ('All', 'System', 'User') AND @dbType NOT LIKE '-%'
BEGIN
    SET @rc = 2
    GOTO EXIT_ROUTINE
END

IF @dbType LIKE '-%' AND @version = '8'
BEGIN
    IF NOT EXISTS (SELECT * FROM master.dbo.sysdatabases WHERE [name] = SUBSTRING(@dbType, 2, DATALENGTH(@dbType)))
    BEGIN
        SET @rc = 3
        GOTO EXIT_ROUTINE
    END
END
ELSE IF @dbType LIKE '-%' AND @version = '9'
BEGIN
    IF NOT EXISTS (SELECT * FROM master.sys.databases WHERE [name] = SUBSTRING(@dbType, 2, DATALENGTH(@dbType)))
    BEGIN
        SET @rc = 3
        GOTO EXIT_ROUTINE
    END
END

IF @bkpType IS NOT NULL AND @bkpType NOT IN ('Full', 'TLog', 'Diff')
BEGIN
    SET @rc = 4
    GOTO EXIT_ROUTINE
END

IF @dbType = 'System' AND @bkpType <> 'Full'
BEGIN
    SET @rc = 5
    GOTO EXIT_ROUTINE
END

IF @liteSpeed IS NOT NULL AND @liteSpeed NOT IN ('N', 'Y')
BEGIN
    SET @rc = 6
    GOTO EXIT_ROUTINE
END

-- use the default backup directory if @path is null
IF @path IS NULL
    EXEC master.dbo.xp_instance_regread N'HKEY_LOCAL_MACHINE',N'Software\Microsoft\MSSQLServer\MSSQLServer',N'BackupDirectory', @path output, 'no_output'

-- we need the backslash after the path, so add it if it wasn't provided in the input parameter
IF RIGHT(@path, 1) <> '\'
    SET @path = @path + '\'

CREATE TABLE #WhichDatabase(dbName SYSNAME NOT NULL)

-- put the databases to be backed up into temp table
IF @dbType LIKE '-%'
BEGIN
    IF @bkpType = 'TLog' AND DATABASEPROPERTYEX(SUBSTRING(@dbType, 2, DATALENGTH(@dbType)), 'RECOVERY') = 'SIMPLE'
    BEGIN
        SET @rc = 7
        GOTO EXIT_ROUTINE
    END
    
    IF @edition = 3
    BEGIN
        IF @version = '8'
        BEGIN
            IF EXISTS (SELECT * FROM msdb.dbo.log_shipping_databases WHERE database_name = SUBSTRING(@dbType, 2, DATALENGTH(@dbType)))
            BEGIN
                SET @rc = 8
                GOTO EXIT_ROUTINE
            END
        END
        ELSE IF @version = '9' 
        BEGIN
            IF EXISTS (SELECT * FROM msdb.dbo.log_shipping_primary_databases WHERE primary_database = SUBSTRING(@dbType, 2, DATALENGTH(@dbType)))
            BEGIN
                SET @rc = 8
                GOTO EXIT_ROUTINE
            END
        END
    END

    IF @version = '9'
    BEGIN
        IF EXISTS (SELECT * FROM master.sys.databases WHERE [name] = SUBSTRING(@dbType, 2, DATALENGTH(@dbType)) AND source_database_id IS NOT NULL)
        BEGIN
            SET @rc = 11
            GOTO EXIT_ROUTINE
        END
    END

    INSERT INTO #WhichDatabase(dbName)
    VALUES(SUBSTRING(@dbType, 2, DATALENGTH(@dbType))) 
END
ELSE IF @dbType = 'All' 
BEGIN
    IF @edition = 3 AND @version = '8'
        INSERT INTO #WhichDatabase (dbName)
        SELECT [name]
        FROM master.dbo.sysdatabases
        WHERE 
            [name] NOT IN ('tempdb', 'ReportServerTempDB') AND
            [name] NOT IN (SELECT database_name FROM msdb.dbo.log_shipping_databases) AND
            DATABASEPROPERTYEX([name], 'IsInStandBy') = 0 AND
            DATABASEPROPERTYEX([name], 'Status') = 'ONLINE'
        ORDER BY [name]
    ELSE IF @edition = 3 AND @version = '9'
        INSERT INTO #WhichDatabase (dbName)
        SELECT [name]
        FROM master.sys.databases
        WHERE 
            [name] NOT IN ('tempdb', 'ReportServerTempDB') AND
            [name] NOT IN (SELECT primary_database FROM msdb.dbo.log_shipping_primary_databases) AND
            DATABASEPROPERTYEX([name], 'IsInStandBy') = 0 AND
            DATABASEPROPERTYEX([name], 'Status') = 'ONLINE'
        ORDER BY [name]
    ELSE IF @version = '8'
        INSERT INTO #WhichDatabase (dbName)
        SELECT [name]
        FROM master.dbo.sysdatabases
        WHERE 
            [name] NOT IN ('tempdb', 'ReportServerTempDB') AND
            DATABASEPROPERTYEX([name], 'IsInStandBy') = 0 AND
            DATABASEPROPERTYEX([name], 'Status') = 'ONLINE'
        ORDER BY [name]
    ELSE -- version is 9
        INSERT INTO #WhichDatabase (dbName)
        SELECT [name]
        FROM master.sys.databases
        WHERE 
            [name] NOT IN ('tempdb', 'ReportServerTempDB') AND
            DATABASEPROPERTYEX([name], 'IsInStandBy') = 0 AND
            DATABASEPROPERTYEX([name], 'Status') = 'ONLINE'
        ORDER BY [name]
END
ELSE IF @dbType = 'System'
BEGIN
    IF @version = 8
        INSERT INTO #WhichDatabase (dbName)
        SELECT [name]
        FROM master.dbo.sysdatabases
        WHERE [name] IN ('master', 'model', 'msdb')
        ORDER BY [name]
    ELSE
        INSERT INTO #WhichDatabase (dbName)
        SELECT [name]
        FROM master.sys.databases
        WHERE [name] IN ('master', 'model', 'msdb')
        ORDER BY [name]
END
ELSE IF @dbType = 'User'
BEGIN
    IF @edition = 3 AND @version = '8'
        INSERT INTO #WhichDatabase (dbName)
        SELECT [name]
        FROM master.dbo.sysdatabases
        WHERE 
            [name] NOT IN ('master', 'model', 'msdb', 'tempdb', 'ReportServerTempDB') AND
            [name] NOT IN (SELECT database_name FROM msdb.dbo.log_shipping_databases) AND
            DATABASEPROPERTYEX([name], 'IsInStandBy') = 0 AND
            DATABASEPROPERTYEX([name], 'Status') = 'ONLINE'
        ORDER BY [name]
    ELSE IF @edition = 3 AND @version = '9'
        INSERT INTO #WhichDatabase (dbName)
        SELECT [name]
        FROM master.sys.databases
        WHERE 
            [name] NOT IN ('master', 'model', 'msdb', 'tempdb', 'ReportServerTempDB') AND
            [name] NOT IN (SELECT primary_database FROM msdb.dbo.log_shipping_primary_databases) AND
            DATABASEPROPERTYEX([name], 'IsInStandBy') = 0 AND
            DATABASEPROPERTYEX([name], 'Status') = 'ONLINE'
        ORDER BY [name]
    ELSE IF @version = '8'
        INSERT INTO #WhichDatabase (dbName)
        SELECT [name]
        FROM master.dbo.sysdatabases
        WHERE 
            [name] NOT IN ('master', 'model', 'msdb', 'tempdb', 'ReportServerTempDB') AND
            DATABASEPROPERTYEX([name], 'IsInStandBy') = 0 AND
            DATABASEPROPERTYEX([name], 'Status') = 'ONLINE'
        ORDER BY [name]
    ELSE
        INSERT INTO #WhichDatabase (dbName)
        SELECT [name]
        FROM master.sys.databases
        WHERE 
            [name] NOT IN ('master', 'model', 'msdb', 'tempdb', 'ReportServerTempDB') AND
            DATABASEPROPERTYEX([name], 'IsInStandBy') = 0 AND
            DATABASEPROPERTYEX([name], 'Status') = 'ONLINE'
        ORDER BY [name]
END
ELSE -- no databases to be backed up
BEGIN
    SET @rc = 9
    GOTO EXIT_ROUTINE
END

-- Remove snapshots
IF @version = '9'
    DELETE t
    FROM #WhichDatabase t 
    INNER JOIN master.sys.databases d
    ON t.dbName = d.[name]
    WHERE d.source_database_id IS NOT NULL

-- Get the database to be backed up
SELECT TOP 1 @dbName = dbName
FROM #WhichDatabase

SET @rowCnt = @@ROWCOUNT

-- Iterate throught the temp table until no more databases need to be backed up
WHILE @rowCnt <> 0
BEGIN 

    IF @bkpType = 'TLog' AND @dbType IN ('All', 'User') AND DATABASEPROPERTYEX(@dbName, 'RECOVERY') = 'SIMPLE'
        PRINT 'Skipping transaction log backup of ' + @dbName
    ELSE IF @bkpType = 'Diff' AND @dbName IN ('master', 'model', 'msdb')
        PRINT 'Skipping differential backup of ' + @dbName
    ELSE
    BEGIN
        -- Build the dir command that will check to see if the directory exists
        SET @cmd = 'dir ' + @path + @dbName
    
        -- Run the dir command, put output of xp_cmdshell into @result
        EXEC @result = master..xp_cmdshell @cmd, NO_OUTPUT
    
        -- If the directory does not exist, we must create it
        IF @result <> 0
        BEGIN
            -- Build the mkdir command        
            SET @cmd = 'mkdir ' + @path + @dbName
    
            -- Create the directory
            EXEC master..xp_cmdshell @cmd, NO_OUTPUT
    
            IF @@ERROR <> 0
            BEGIN
                SET @rc = 10
                GOTO EXIT_ROUTINE
            END
        END
        -- The directory exists, so let's delete files older than two days
        ELSE IF @retention <> -1
        BEGIN
            -- Stores the name of the file to be deleted
            DECLARE @whichFile VARCHAR(1000)
    
            CREATE TABLE #DeleteOldFiles(DirInfo VARCHAR(7000))
    
            -- Build the command that will list out all of the files in a directory
            SELECT @cmd = 'dir ' + @path + @dbName + ' /OD'
    
            -- Run the dir command and put the results into a temp table
            INSERT INTO #DeleteOldFiles
            EXEC master..xp_cmdshell @cmd
    
            -- Delete all rows from the temp table except the ones that correspond to the files to be deleted
            DELETE FROM #DeleteOldFiles
            WHERE ISDATE(SUBSTRING(DirInfo, 1, 10)) = 0 OR DirInfo LIKE '%<DIR>%' OR SUBSTRING(DirInfo, 1, 10) >= GETDATE() - @retention
    
            -- Get the file name portion of the row that corresponds to the file to be deleted
            SELECT TOP 1 @whichFile = SUBSTRING(DirInfo, LEN(DirInfo) -  PATINDEX('% %', REVERSE(DirInfo)) + 2, LEN(DirInfo)) 
            FROM #DeleteOldFiles        
    
            SET @rowCnt = @@ROWCOUNT
            
            -- Interate through the temp table until there are no more files to delete
            WHILE @rowCnt <> 0
            BEGIN
                -- Build the del command
                SELECT @cmd = 'del ' + @path + + @dbName + '\' + @whichFile + ' /Q /F'
                
                -- Delete the file
                EXEC master..xp_cmdshell @cmd, NO_OUTPUT
                
                -- To move to the next file, the current file name needs to be deleted from the temp table
                DELETE FROM #DeleteOldFiles
                WHERE SUBSTRING(DirInfo, LEN(DirInfo) -  PATINDEX('% %', REVERSE(DirInfo)) + 2, LEN(DirInfo))  = @whichFile
    
                -- Get the file name portion of the row that corresponds to the file to be deleted
                SELECT TOP 1 @whichFile = SUBSTRING(DirInfo, LEN(DirInfo) -  PATINDEX('% %', REVERSE(DirInfo)) + 2, LEN(DirInfo)) 
                FROM #DeleteOldFiles
            
                SET @rowCnt = @@ROWCOUNT
            END
            DROP TABLE #DeleteOldFiles
        END
        -- Get the current date using style 120, remove all dashes, spaces, and colons
        SET @now = REPLACE(REPLACE(REPLACE(CONVERT(VARCHAR(50), GETDATE(), 120), '-', ''), ' ', ''), ':', '')
    
        SET @extension =
            CASE
                WHEN @bkpType = 'Full' THEN '.BAK'
                WHEN @bkpType = 'TLog' THEN '.TRN'
                ELSE '.DIF'
            END
    
        -- Build the backup path and file name, backup the database
        IF @liteSpeed = 'N'
        BEGIN
            SET @fileName = @path + @dbName + '\' + @dbName + '_' + @now + @extension
            IF @bkpType = 'FULL'
                BACKUP DATABASE @dbName
                TO DISK = @filename
                WITH INIT
            ELSE IF @bkpType = 'DIFF'
                BACKUP DATABASE @dbName
                TO DISK = @filename
                WITH INIT, DIFFERENTIAL
            ELSE
                BACKUP LOG @dbName
                TO DISK = @filename
                WITH INIT    
        END
        ELSE
        BEGIN
            SET @fileName = @path + @dbName + '\' + @dbName + '_LS_' + @now + @extension
    
            DECLARE @regOutput varchar(20) -- stores the output from the registry
            DECLARE @numProcs INT -- stores the number of processors that the server has registered

            -- Get the number of processors that the server has
            EXEC master..xp_regread 
                  @rootkey = 'HKEY_LOCAL_MACHINE', 
                  @key = 'SYSTEM\CurrentControlSet\Control\Session Manager\Environment\',
                  @value_name = 'NUMBER_OF_PROCESSORS',
                  @value = @regOutput OUTPUT
            
            --  We want n - 1 threads, where n is the number of processors
            SET @numProcs = CONVERT(int, @regOutput) - 1
    
            IF @bkpType = 'FULL'
                EXEC master.dbo.xp_backup_database
                    @database = @dbName,
                    @filename = @fileName,
                    @threads = @numProcs,
                    @init = 1
            ELSE IF @bkpType = 'DIFF'
                EXEC master.dbo.xp_backup_database
                    @database = @dbName,
                    @filename = @fileName,
                    @threads = @numProcs,
                    @init = 1,
                    @with = 'DIFFERENTIAL'
            ELSE
                EXEC master.dbo.xp_backup_log
                    @database = @dbName,
                    @filename = @fileName,
                    @threads = @numProcs,
                    @init = 1
        END
    END
        -- To move onto the next database, the current database name needs to be deleted from the temp table
        DELETE FROM #WhichDatabase
        WHERE dbName = @dbName
    
        -- Get the database to be backed up
        SELECT TOP 1 @dbName = dbName
        FROM #WhichDatabase
    
        SET @rowCnt = @@ROWCOUNT
        
        -- Let the system rest for 5 seconds before starting on the next backup
        WAITFOR DELAY '00:00:05'
END

SET @rc = 0

EXIT_ROUTINE:

IF @rc <> 0
BEGIN
    DECLARE @rm varchar(500)
    DECLARE @error table (returnCode int PRIMARY KEY CLUSTERED, returnMessage varchar(500))

    INSERT INTO @error(returnCode, returnMessage)
    SELECT  0, 'Success' UNION ALL
    SELECT  1, 'Version is not 2000 or 2005' UNION ALL
    SELECT  2, 'Invalid option passed to @dbType' UNION ALL
    SELECT  3, 'Database passed to @dbType does not exist' UNION ALL
    SELECT  4, 'Invalid option passed to @bkpType' UNION ALL
    SELECT  5, 'Only full backups are allowed on system databases' UNION ALL
    SELECT  6, 'Invalid option passed to @liteSpeed' UNION ALL
    SELECT  7, 'Can not backup tlog when using SIMPLE recovery model' UNION ALL
    SELECT  8, 'Will not backup the tlog on a log shipped database' UNION ALL
    SELECT  9, 'No databases to be backed up' UNION ALL
    SELECT 10, 'Unable to create directory' UNION ALL
    SELECT 11, 'Can not backup database snapshots'

    SELECT @rm = returnMessage 
    FROM @error 
    WHERE returnCode = @rc

    RAISERROR(@rm, 16, 1)
END

RETURN @rc