The Art of SQL Server FILESTREAM - Red Gate Software

Chapter 12: Planning, Configuration and Best PracticesInitially, I was surprised that, when the test was run with short file names enabled, theduration went up with each lap (up to Lap 9) and then fell down to 3 seconds from 106.The same happened at Lap 19 too. Then I realized that the delay has to do with theamount of data NTFS has to look at before creating a new file. After Lap 9, the file namepattern changed and the same happened after Lap 19. It indicates that not only thenumber of files in the folder, but also the way files are named, affects the performancewhen short file names are enabled.SQL Server names FILESTREAM data files based on the LSN that created theFILESTREAM data file. Based on the workload and usage pattern on your server, the filenames on disk may or may not follow a specific pattern. The system overhead to createshort file names depends on the number of files with similar names in the same folder.If the file names created are similar, you might notice a performance difference afterdisabling short file names. It is important to note that the impact of short file namescomes into the picture only when new files are created. If your application does not createnew files, the impact of the change may often not be noticeable.Compressing FILESTREAM dataWhen data is compressed, the I/O pressure on the system is reduced because less datais read from, and written to, the disk. On the other hand, CPU usage increases becausethe storage engine has to compress the data before writing to the disk, and decompressit on reading. Depending upon your workload, CPU, and I/O subsystem capabilities,compression may or may not help. In most cases, I have seen that compression helps ifthe data is compressible.The SQL Server row- and page-level compression feature does not compressFILESTREAM data files. However, SQL Server allows FILESTREAM data files to be storedon compressed disk volumes. This will reduce the storage space needed for the data. Thedecision to go with compressed FILESTREAM storage should be taken only after clearly443