I recently looked at an issue where free space on a backup drive was running low. One option was to increase the storage. Another was to look at the composition of the backups and see if I could try compressing backups with Litespeed for SQL Server.
2 particular backups stood out. Database1 was 93GB and Database2 was 297GB. Incidently, this was only half of the total size as we stripe across 2 drives so the total size was 186GB and 594GB.
Example backup script for Litespeed.
exec master.dbo.xp_backup_database @database = 'Database1', @filename = 'D:\Backup\Database1\Database1_1.BKP', @filename = 'G:\Backup\Database1\Database1_2.BKP', @backupname = Database1 backup', @desc = 'Backup of Database1', @encryptionkey = 'LiteSp1234567', @cryptlevel = 8, @init = 1, @logging = 0, @throttle = 99, @comment = '', @with = 'SKIP', @with = 'STATS = 5', @compressionlevel = 1
For the purposes of this post, the line we are most interested in is @compressionlevel = 1. By increasing @compressionlevel on a scale from one to eight, we can reduce the size of our backups. One thing to note is that the higher the level of compression, the higher the CPU utilisation will be. More highly compressed backups will usually take more time. It is worth testing the backups using incremental increases in @compressionlevel to find the one that best suits your server.
LiteSpeed for SQL Server 7.5 allows a compression level of 1 – 8.
1 = Medium Compression
2 = Medium High Compression
3-6 = High Compression
7-8 = Extreme Compression.
(Previous versions allowed 9-11 but these are now classed as Level 8)
It is worth testing the backups using incremental increase in @compressionlevel to find the one that best suits your server.
In the end, I opted for @compressionLevel = 5 for Database1 and @CompressionLevel = 3 for Database2. The increased backup time to use @compressionlevel=5 for Database1 is justifed, given the 64GB reduction in backup size. For Database 2 backup, there was too large a jump in processing time between levels 3 and 5. If we had no option, we could live with it but the original reduction in size by using @CompressionLevel = 3 was sufficient.
Side note: As a side benefit I wasn’t considering, our backup team advised the tape backup duration reduced by 1.5 hours so there was a positive knock on effect for another team too.