FullOfLove
12-17-2007, 09:00 PM
The reason for this is that performance under different cluster sizes is directly related to the average file size on the volume; for example, you may find that larger cluster sizes deliver better performance than smaller ones or vice versa. However, you should always experiment thoroughly before committing to a custom cluster size choice. The nice thing here is that if you choose to just go ahead with NT’s default size and not bother, you’ll still get good performance. The major benefit of smaller cluster sizes is that there is less disk space wasted; it’s unlikely that you’ll see large performance differences between different cluster sizes.
NTFS COMPRESSION
Another important feature of NTFS, which was new with Windows NT version 3.51, is the ability to selectively compress individual files and folders on a disk. Although most people think of compression strictly in terms of disk space savings, you might be interested to know that compression can also have major performance benefits. However, these benefits come at a price: CPU utilization.
In our lab experimentation with NTFS compression during the writing of this book, we tested a number of machines with and without NTFS compression. On smaller volume sizes (generally sub-2GB non-RAID volumes), we were amazed to discover that volumes using NTFS compression delivered overall performance increases of up to 50 percent. It seemed too good to be true until we simultaneously monitored CPU utilization during a subsequent run of the same benchmarks using a compressed NTFS volume. We saw average CPU utilization on these tests jump from a mild 10–18 percent range on the uncompressed NTFS volume tests to a whopping 30–80 percent range on the compressed NTFS volume tests. Therein lies the rub. Additionally, we saw major performance decreases when using NTFS compression on large volume sizes (between 4GB and 17GB) and software-based fault-tolerant RAID volumes (which already incur a CPU hit due to the RAID redundancy operations).
To summarize, you can significantly increase disk performance using NTFS compression in some cases on smaller volume sizes, but you’ll likely do so with a significant hit in CPU utilization. However, this effect might be tolerable on systems with extremely fast processors or multiple installed processors. As always, it is recommended that you test this feature on a nonproduction machine to experiment with it prior to deploying it “live” in your environment.
If you do choose to employ compression on your NTFS volume, you’ll be glad to know that compression can be done on a selective basis. In fact, NTFS compression goes down to the file level, meaning that you can compress individual files and directories on a case-by-case basis; you don’t have to compress the entire volume as is the case with compression methods used by other operating systems. However, if desired, you can also compress an entire NTFS volume simply by compressing the volume’s root folder. With NT 3.5x, you compress files and folders with File Manager. In NT 4.0, you select a file or folder’s Properties dialog by right-clicking on the file or folder and choosing Properties.
TIP: To compress an entire drive, open the My Computer (http://www.windowsitlibrary.com/Content/435/07/8.html#) desktop folder, right-click on the NTFS volume to be compressed, and choose Properties. In the dialog that appears, check the Compress <drive:> box and choose OK. You will be asked if you wish to also compress all the subfolders of the drive as well; if this is the case, choose Yes. Otherwise, only the root folder of the volume will be compressed.
Figure 7-19 (http://www.windowsitlibrary.com/Content/435/07/files/fig7_19.html) is an example of the dialog to compress an NTFS volume.
Figure 7-20 (http://www.windowsitlibrary.com/Content/435/07/files/fig7_20.html) is an example of the dialog to compress an individual folder on an NTFS volume.
You can also compress a file or folder with the command-line utility COMPACT.EXE. The command format to do this is: COMPACT [/c | /u] [/s[:dir]] [/a] [/i] [/f] [/q] [filename [...]]
NOTE: When used without any command-line parameters, COMPACT displays the compression status of the current directory and any files it contains. You can also use multiple filenames and wildcards (however, you must put spaces between multiple parameters).
NTFS TUNING
In addition to what has been described elsewhere in this chapter, there are a few other things you can do to optimize the performance of NTFS volumes. Specifically, there are several Registry modifications you can make to disable certain features of NTFS that may not be necessary in your environment.
The first such modification is a system change that disables NTFS’s automatic creation of MS-DOS style 8.3 format “short names” for files stored on NTFS volumes. As you probably know, Windows NT supports the use of long filenames on both NTFS and FAT volumes. In both cases, NT automatically creates a short name version of each file stored on a volume in 8.3 naming format. This maintains compatibility with 16-bit operating systems and applications that access the volume (such as MS-DOS, Windows 3.x, Windows for Workgroups, and applications that run under these operating systems). However, this procedure also incurs additional write overhead to add the second Master File Table entry for each file and directory. With NTFS volumes, it is possible to disable this automatic name generation via a Registry modification (there is no such equivalent for FAT volumes).
You may want to consider making this modification if your network is in pure 32-bit networking environment with 100 percent 32-bit operating systems and applications. To enable this change, open one of the Windows NT Registry Editor utilities and locate the following key and value: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\FileSystem Value: NtfsDisable8dot3NameCreation
Default Data: 0 (false)
To disable 8.3 short-name generation, set the data for this value to 1.
There are several important points to remember if you’re considering making this change. First, be very sure that your network does not now contain, and will not in the future contain, any systems that use DOS, Windows 3.x, or Windows for Workgroups 3.x. These systems cannot use files on an NTFS volume without 8.3-style names. Also, be aware that using 16-bit applications (e.g., MS-DOS or Win16 applications) on an NTFS volume without 8.3 names may cause application incompatibilities or crashes. Finally, be aware that changing this Registry value affects only future files stored on the volume. Existing files retain their previously created 8.3 version names until you remove the files from the volume. If you want to start with a clean slate, you’ll have to set the Registry value to 1, move all the files to another volume or tape, and then move the files back to the original volume.
CAUTION: Disabling NTFS 8.3 short-name creation on a Windows NT 3.51 Server running Microsoft Exchange Server (http://www.windowsitlibrary.com/Content/435/07/8.html#) may prevent Exchange Custom Forms from working properly. If you are using these products in this configuration, it’s recommended that you leave 8.3 name creation enabled.
In addition to the 8.3 name generation feature, there is one other Registry modification that we can make to create some improvement in NTFS’s performance. A value named NtfsDisableLastAccessUpdate controls whether NTFS updates the LastAccess time/date stamp on directories as NTFS traverses the directory structure. Disabling these last access updates can reduce NTFS’s overhead without significantly impairing functionality. The default value is 0 (NTFS updates directory time/date stamps); change the value to 1 to disable updates. If you don’t see the NtfsDisableLastAccessUpdate value listed, you can manually add it as a REG_DWORD value and then set the value’s data as 1. However, if you add it, be very certain to spell the value name correctly including capitalization.
DISK FRAGMENTATION AND OPTIMIZATION
One of the most important practices in maintaining a well-optimized disk subsystem under any operating system is minimizing the level of file fragmentation that exists on the system’s various drive volumes. This can be accomplished by regularly running a disk defragmentation utility that defragments – that is, makes contiguous – every file on the volume. In addition, these utilities are also capable of defragmenting the free disk space on the volume, which is also beneficial to improving volume performance.
Fragmentation adversely affects performance because additional head and platter movements are required to access a file which is stored in multiple, noncontiguous locations on a disk. On the other hand, when a file is contiguous, it can be read sequentially in one long burst without requiring additional drive re-positioning.
To maintain optimal disk performance on your Windows NT system, you should regularly run a disk defragmentation tool. The frequency of this process should be proportionate to the level of disk usage on the machine; that is, heavily-accessed network servers should probably have this process run once per week at minimum, whereas workstations with relatively light disk usage may be fine with a monthly or semimonthly disk defragmentation. You can use the disk fragmentation analysis tool included with your defragmentation software to determine the level of fragmentation that currently exists on each volume.
Figure 7-21 (http://www.windowsitlibrary.com/Content/435/07/files/fig7_21.html) shows a Windows NT disk defragmentation utility at work.
COOL PRODUCT TIP: At the time of this writing, there are three commercial disk defragmentation utilities available for Windows NT (http://www.windowsitlibrary.com/Content/435/07/8.html#): Executive Software’s Diskeeper for Windows NT, Norton Speedisk, part of the Norton Utilities for Windows NT available from Symantec Corporation, and Perfect Disk NT by Raxco Software. Information on Diskeeper can be found on Executive Software’s World Wide Web site at: http://www.execsoft.com/ Information on Diskeeper can be found on Executive Software’s (http://www.windowsitlibrary.com/Content/435/07/8.html#) World Wide Web site at: http://www.execsoft.com/ Information on Perfect Disk NT can be found at Raxco’s Web site at: http://www.raxco.com/
ON THE CD: Diskeeper (http://www.windowsitlibrary.com/Content/435/07/8.html#) by Executive Software, the original disk defragmentation utility for Windows NT, is an excellent disk defragmentation tool that works with both FAT and NTFS volumes. Diskeeper also includes a handy disk fragmentation analysis tool, which informs you about the current level of file fragmentation on each of your disk volumes. Diskeeper Lite, the shareware version of Diskeeper, is included on the Optimizing Windows NT CD-ROM. To install the software, follow the directions outlined in Appendix A, “What’s On the CD?,” or point your Web browser to the location of the Optimizing Windows NT CD-ROM in your system and follow the links to install the software.
TIP: When running disk-related benchmarks on your system, don’t forget to run a full file and free space defragmentation before each benchmark test iteration. Otherwise, varying levels of fragmentation may affect your tests and produce skewed or misleading results.
►Source: http://www.windowsitlibrary.com/Content/435/07/8.html
NTFS COMPRESSION
Another important feature of NTFS, which was new with Windows NT version 3.51, is the ability to selectively compress individual files and folders on a disk. Although most people think of compression strictly in terms of disk space savings, you might be interested to know that compression can also have major performance benefits. However, these benefits come at a price: CPU utilization.
In our lab experimentation with NTFS compression during the writing of this book, we tested a number of machines with and without NTFS compression. On smaller volume sizes (generally sub-2GB non-RAID volumes), we were amazed to discover that volumes using NTFS compression delivered overall performance increases of up to 50 percent. It seemed too good to be true until we simultaneously monitored CPU utilization during a subsequent run of the same benchmarks using a compressed NTFS volume. We saw average CPU utilization on these tests jump from a mild 10–18 percent range on the uncompressed NTFS volume tests to a whopping 30–80 percent range on the compressed NTFS volume tests. Therein lies the rub. Additionally, we saw major performance decreases when using NTFS compression on large volume sizes (between 4GB and 17GB) and software-based fault-tolerant RAID volumes (which already incur a CPU hit due to the RAID redundancy operations).
To summarize, you can significantly increase disk performance using NTFS compression in some cases on smaller volume sizes, but you’ll likely do so with a significant hit in CPU utilization. However, this effect might be tolerable on systems with extremely fast processors or multiple installed processors. As always, it is recommended that you test this feature on a nonproduction machine to experiment with it prior to deploying it “live” in your environment.
If you do choose to employ compression on your NTFS volume, you’ll be glad to know that compression can be done on a selective basis. In fact, NTFS compression goes down to the file level, meaning that you can compress individual files and directories on a case-by-case basis; you don’t have to compress the entire volume as is the case with compression methods used by other operating systems. However, if desired, you can also compress an entire NTFS volume simply by compressing the volume’s root folder. With NT 3.5x, you compress files and folders with File Manager. In NT 4.0, you select a file or folder’s Properties dialog by right-clicking on the file or folder and choosing Properties.
TIP: To compress an entire drive, open the My Computer (http://www.windowsitlibrary.com/Content/435/07/8.html#) desktop folder, right-click on the NTFS volume to be compressed, and choose Properties. In the dialog that appears, check the Compress <drive:> box and choose OK. You will be asked if you wish to also compress all the subfolders of the drive as well; if this is the case, choose Yes. Otherwise, only the root folder of the volume will be compressed.
Figure 7-19 (http://www.windowsitlibrary.com/Content/435/07/files/fig7_19.html) is an example of the dialog to compress an NTFS volume.
Figure 7-20 (http://www.windowsitlibrary.com/Content/435/07/files/fig7_20.html) is an example of the dialog to compress an individual folder on an NTFS volume.
You can also compress a file or folder with the command-line utility COMPACT.EXE. The command format to do this is: COMPACT [/c | /u] [/s[:dir]] [/a] [/i] [/f] [/q] [filename [...]]
NOTE: When used without any command-line parameters, COMPACT displays the compression status of the current directory and any files it contains. You can also use multiple filenames and wildcards (however, you must put spaces between multiple parameters).
NTFS TUNING
In addition to what has been described elsewhere in this chapter, there are a few other things you can do to optimize the performance of NTFS volumes. Specifically, there are several Registry modifications you can make to disable certain features of NTFS that may not be necessary in your environment.
The first such modification is a system change that disables NTFS’s automatic creation of MS-DOS style 8.3 format “short names” for files stored on NTFS volumes. As you probably know, Windows NT supports the use of long filenames on both NTFS and FAT volumes. In both cases, NT automatically creates a short name version of each file stored on a volume in 8.3 naming format. This maintains compatibility with 16-bit operating systems and applications that access the volume (such as MS-DOS, Windows 3.x, Windows for Workgroups, and applications that run under these operating systems). However, this procedure also incurs additional write overhead to add the second Master File Table entry for each file and directory. With NTFS volumes, it is possible to disable this automatic name generation via a Registry modification (there is no such equivalent for FAT volumes).
You may want to consider making this modification if your network is in pure 32-bit networking environment with 100 percent 32-bit operating systems and applications. To enable this change, open one of the Windows NT Registry Editor utilities and locate the following key and value: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\FileSystem Value: NtfsDisable8dot3NameCreation
Default Data: 0 (false)
To disable 8.3 short-name generation, set the data for this value to 1.
There are several important points to remember if you’re considering making this change. First, be very sure that your network does not now contain, and will not in the future contain, any systems that use DOS, Windows 3.x, or Windows for Workgroups 3.x. These systems cannot use files on an NTFS volume without 8.3-style names. Also, be aware that using 16-bit applications (e.g., MS-DOS or Win16 applications) on an NTFS volume without 8.3 names may cause application incompatibilities or crashes. Finally, be aware that changing this Registry value affects only future files stored on the volume. Existing files retain their previously created 8.3 version names until you remove the files from the volume. If you want to start with a clean slate, you’ll have to set the Registry value to 1, move all the files to another volume or tape, and then move the files back to the original volume.
CAUTION: Disabling NTFS 8.3 short-name creation on a Windows NT 3.51 Server running Microsoft Exchange Server (http://www.windowsitlibrary.com/Content/435/07/8.html#) may prevent Exchange Custom Forms from working properly. If you are using these products in this configuration, it’s recommended that you leave 8.3 name creation enabled.
In addition to the 8.3 name generation feature, there is one other Registry modification that we can make to create some improvement in NTFS’s performance. A value named NtfsDisableLastAccessUpdate controls whether NTFS updates the LastAccess time/date stamp on directories as NTFS traverses the directory structure. Disabling these last access updates can reduce NTFS’s overhead without significantly impairing functionality. The default value is 0 (NTFS updates directory time/date stamps); change the value to 1 to disable updates. If you don’t see the NtfsDisableLastAccessUpdate value listed, you can manually add it as a REG_DWORD value and then set the value’s data as 1. However, if you add it, be very certain to spell the value name correctly including capitalization.
DISK FRAGMENTATION AND OPTIMIZATION
One of the most important practices in maintaining a well-optimized disk subsystem under any operating system is minimizing the level of file fragmentation that exists on the system’s various drive volumes. This can be accomplished by regularly running a disk defragmentation utility that defragments – that is, makes contiguous – every file on the volume. In addition, these utilities are also capable of defragmenting the free disk space on the volume, which is also beneficial to improving volume performance.
Fragmentation adversely affects performance because additional head and platter movements are required to access a file which is stored in multiple, noncontiguous locations on a disk. On the other hand, when a file is contiguous, it can be read sequentially in one long burst without requiring additional drive re-positioning.
To maintain optimal disk performance on your Windows NT system, you should regularly run a disk defragmentation tool. The frequency of this process should be proportionate to the level of disk usage on the machine; that is, heavily-accessed network servers should probably have this process run once per week at minimum, whereas workstations with relatively light disk usage may be fine with a monthly or semimonthly disk defragmentation. You can use the disk fragmentation analysis tool included with your defragmentation software to determine the level of fragmentation that currently exists on each volume.
Figure 7-21 (http://www.windowsitlibrary.com/Content/435/07/files/fig7_21.html) shows a Windows NT disk defragmentation utility at work.
COOL PRODUCT TIP: At the time of this writing, there are three commercial disk defragmentation utilities available for Windows NT (http://www.windowsitlibrary.com/Content/435/07/8.html#): Executive Software’s Diskeeper for Windows NT, Norton Speedisk, part of the Norton Utilities for Windows NT available from Symantec Corporation, and Perfect Disk NT by Raxco Software. Information on Diskeeper can be found on Executive Software’s World Wide Web site at: http://www.execsoft.com/ Information on Diskeeper can be found on Executive Software’s (http://www.windowsitlibrary.com/Content/435/07/8.html#) World Wide Web site at: http://www.execsoft.com/ Information on Perfect Disk NT can be found at Raxco’s Web site at: http://www.raxco.com/
ON THE CD: Diskeeper (http://www.windowsitlibrary.com/Content/435/07/8.html#) by Executive Software, the original disk defragmentation utility for Windows NT, is an excellent disk defragmentation tool that works with both FAT and NTFS volumes. Diskeeper also includes a handy disk fragmentation analysis tool, which informs you about the current level of file fragmentation on each of your disk volumes. Diskeeper Lite, the shareware version of Diskeeper, is included on the Optimizing Windows NT CD-ROM. To install the software, follow the directions outlined in Appendix A, “What’s On the CD?,” or point your Web browser to the location of the Optimizing Windows NT CD-ROM in your system and follow the links to install the software.
TIP: When running disk-related benchmarks on your system, don’t forget to run a full file and free space defragmentation before each benchmark test iteration. Otherwise, varying levels of fragmentation may affect your tests and produce skewed or misleading results.
►Source: http://www.windowsitlibrary.com/Content/435/07/8.html