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Creating and Using RAID-5 Volumes RAID-5 volumes can be created using three to 32 disks.The parity information can be used to regenerate the missing data should one disk fail. If you lose more than one disk, however, all your data will be lost. As with mirrored volumes, RAID-5 volumes cannot be extended. However, RAID-5 volumes offer more efficient disk utilization than mirrored volumes.You lose the storage space equivalent to one disk in the RAID-5 volume because it is used for parity information. For example, if you have five disks and you lose the storage space of one disk, you operate at 80 percent disk utilization. If you increase the number of disks in your RAID-5 volume, you will get even better disk utilization. For example, if you use 10 disks instead of five, you will operate at 90 percent utilization instead of 80 percent utilization. On the other hand, it takes longer to get your system back up and running after a disk failure with RAID-5, as opposed to mirrors, because you must go through the process of regenerating the data from parity. Use RAID-5 volumes in the following situations: ■ You need the boosted read performance of a striped volume, but you must have fault tol- erance. ■ You want fault tolerance with the most efficient level of disk utilization possible. ■ You need fault tolerance, but you have too many disks to use a mirror. Creating a RAID-5 volume 1. Right-click the unallocated space on the disk on which you want to create a RAID-5 volume. 2. Click New Volume on the context menu.This will start the New Volume Wizard,as shown in Figure 5.63. 3. Click Next to continue. 146 Chapter 5 • Managing Physical and Logical Disks Figure 5.62 Synchronizing a Mirrored Volume 301_BD_W2k3_05.qxd 5/12/04 12:32 PM Page 146 4. In the Select Volume Type window (Figure 5.64), select RAID-5. 5. Click Next to continue. 6. You will next be prompted to select the disks to use for the RAID-5 volume, as shown in Figure 5.65. Select the disks you want to use. 7. Select the amount of space to be used for the striped volume and click Next to continue. Managing Physical and Logical Disks • Chapter 5 147 Figure 5.63 Using the New Volume Wizard to Create a RAID-5 Volume Figure 5.64 Selecting to Create a RAID-5 Volume Figure 5.65 Adding Disks to the RAID-5 Volume 301_BD_W2k3_05.qxd 5/12/04 12:32 PM Page 147 8. Next you need to identify your new RAID-5 volume. Select a drive letter or choose to mount the new volume to an NTFS folder. For this example, we assign the new volume the drive letter D, as shown in Figure 5.66. 9. Next, you can format your new RAID-5 volume.You can format a RAID-5 volume as FAT, FAT32, or NTFS, or you can choose not to format the volume at this time. For this example, choose NTFS, as shown in Figure 5.67, and click Next to continue. 10. You will next see the Completing the New Volume Wizard window, as shown in Figure 5.68. Read the summary to verify that you made the correct selections and click Finish to complete the process. 148 Chapter 5 • Managing Physical and Logical Disks Figure 5.66 Assigning a Drive Letter or Path Figure 5.67 Formatting the RAID-5 Volume 301_BD_W2k3_05.qxd 5/12/04 12:32 PM Page 148 Optimizing Disk Performance Optimizing disk performance is an important part of managing a server. Consider the disk-oriented tasks that take place on a typical day on the typical server. Users save data to their home directories. They send e-mail back and forth (which is saved in a database on the server).They print docu- ments.They access shared files. All these tasks require good disk performance. Two issues you will always run into when managing disks are disk fragmentation and insuffi- cient disk space. Fragmentation problems are not as obvious as disk space problems; when you run out of disk space, you usually find out immediately. However, you may not notice that a disk is frag- mented unless you take the time to check or you notice that performance has degraded. With Windows Server 2003, Microsoft provides ways to manage both of these concerns.The disk defrag- mentation utilities can ensure that your disk is performing at its peak and the disk quotas feature can ensure that you do not run out of disk space. In the following sections, we will discuss how to use these tools to keep your disks at optimum performance levels. Defragmenting Volumes and Partitions Defragmenting the disks on all your servers (especially file servers) can ensure optimal performance and enable you to get more use out of your disks. It is not something that you should do every day, but you definitely need to make it part of your server maintenance routine. Microsoft provides two tools for performing defragmentation. Both tools work with basic and dynamic disks that are for- matted with the FAT, FAT32, or NTFS file systems.These tools are: ■ Disk Defragmenter (graphical utility) ■ Defrag.exe (command-line tool) You will learn how to use each of these tools to defragment your disks. Managing Physical and Logical Disks • Chapter 5 149 Figure 5.68 Finishing the New Volume Wizard 301_BD_W2k3_05.qxd 5/12/04 12:32 PM Page 149 Using the Graphical Defragmenter You can access the graphical defragmenter in several different ways: ■ Click Start | All Programs | Accessories | System Tools | Disk Defragmenter. ■ Right-click My Computer, select Manage, and click Disk Defragmenter in the left console pane. ■ Click Start | All Programs | Administrative Tools | Computer Management and click the Disk Defragmenter in the left console pane. For our examples, we will access the Disk Defragmenter via Computer Management. Note that anyone can open the Disk Defragmenter tool, but only an administrator, or someone with an account that has been delegated the authority, can analyze or defragment a volume. Using the Disk Defragmenter 1. Open Computer Management (click Start | All Programs | Administrative Tools | Computer Management). 2. Click Disk Defragmenter as shown in Figure 5.69. 3. Click the Analyze button.This will analyze your disks and give you a report of how defragmented they are, as shown in Figure 5.70. 150 Chapter 5 • Managing Physical and Logical Disks Figure 5.69 Using Disk Defragmenter from the GUI Figure 5.70 Analyzing Your Hard Disk for Defragmentation 301_BD_W2k3_05.qxd 5/12/04 12:32 PM Page 150 4. Click the View Report button to see the status of your disk.This will give you a report similar to the one shown in Figure 5.71. 5. At this point, you can click Close if you do not want to defragment your disk. If you do want to defragment, click the Defragment button to start the process. 6. You will next see the screen shown in Figure 5.72.You can pause or stop the defragmenta- tion process by clicking Pause or Stop on the Action menu. When the defragmentation process is complete, you will be given the option to view a defragmentation report, as shown in Figure 5.73. Click View Report. Managing Physical and Logical Disks • Chapter 5 151 Figure 5.71 Viewing the Analysis Report Figure 5.72 Defragmenting Your Hard Disk 301_BD_W2k3_05.qxd 5/12/04 12:32 PM Page 151 7. Compare the defragmentation report in Figure 5.74 with the analysis report in Figure 5.71.You should see a decrease in file fragmentation.You can print or save your report for later viewing. When finished, click Close. Viewing the Analysis Report You don’t have to really understand the analysis report in order to defragment your disks.The soft- ware is smart enough to let you know whether or not you need to defrag. However, a lot of good information can be found in the analysis report.This includes the following: ■ Fragmented files and folders Displays the paths and names of the most fragmented files on the volume. ■ Volume size ■ Amount of free space available ■ Average number of fragments per file You can use the average number of fragments per file to gauge how fragmented the volume is.Table 5.3 explains the possible averages. 152 Chapter 5 • Managing Physical and Logical Disks Figure 5.73 Completing Defragmentation Figure 5.74 Viewing the Defragmentation Report 301_BD_W2k3_05.qxd 5/12/04 12:32 PM Page 152 Table 5.3 Describing the Average Number of Fragments per File Average Number of Fragments per File Description 1.00 Most or all files are contiguous. 1.10 Around ten percent of the files are fragmented into two or more sections. 1.20 Around twenty percent of the files are fragmented into two or more sections. 1.30 Around thirty percent of the files are fragmented into two or more sections. 2.00 Most or all of the files are fragmented into two or more sections. Understanding the Disk Defragmenter Interface The Disk Defragmenter provides you with analysis reports and defragmentation reports to alert you to the fragmentation status of your disks. However, the graphical interface of the defragmenter tool also provides much of the same information if you know what to look for.The screenshot in Figure 5.75 was taken immediately after running the defragmentation utility. Let’s analyze the display to determine the information that is available. Notice that Disk Defragmenter runs in a standard MMC, which gives it a familiar feel, with the console tree in the left pane and the details pane on the right. On the right side, the pane is split into a top and a bottom section.The top section shows the volumes and partitions on the machine. The bottom section shows a graphical view of the fragmentation status of the selected volume. There are two bars in the bottom pane, which indicate the following: ■ Estimated disk usage before defragmentation ■ Estimated disk usage after defragmentation By examining these bars, you can see the status of the disk before the defragmentation and the changes that have occurred afterward.These bars are obviously too small to list every cluster on the disk, but they do provide an accurate representation of how fragmented the volume is. Table 5.4 explains the color codes used in these two bars. After running Disk Defragmenter, the goal is to see most of the red in the top bar replaced with blue. Table 5.4 Understanding the Estimated Disk Usage Bars in Disk Defragmenter Color Description Red Most of the clusters are fragmented files. Blue Most of the clusters are contiguous files. Green Most of the clusters are files that cannot be moved from their current location. This could include paging files, or files used by the file system. White Most of the clusters are free space. Managing Physical and Logical Disks • Chapter 5 153 301_BD_W2k3_05.qxd 5/12/04 12:32 PM Page 153 Using Defrag.exe If you are comfortable with the Disk Defragmenter tool but prefer a character-based utility, you will feel right at home with defrag.exe, the command prompt equivalent of Disk Defragmenter. Defrag.exe does everything that Disk Defragmenter does and in addition, it supports scripting.You can use defrag.exe in a script to schedule analysis and defragmentation of your servers. Scripting is the primary reason to use defrag.exe instead of Disk Defragmenter.Table 5.5 explains the parameters for defrag.exe. Defrag.exe uses the following syntax: defrag <volume> [-a] [-f] [-v] [-?] volume drive letter or mount point (d: or d:\vol\mountpoint) Table 5.5 Understanding Defrag.exe Parameters Parameters Description Volume The drive letter or mount point to be defragmented. A Analyzes the volume and displays an analysis summary indicating whether you should defragment the volume. F Forces defragmentation of the volume when low on free space. V Displays the complete analysis and defragmentation reports (not just a sum- mary). When used with the /a switch, it displays only the analysis report. When used alone, it displays both the analysis and defragmentation reports. ? Displays help. 154 Chapter 5 • Managing Physical and Logical Disks Figure 5.75 Viewing Your Disk After Defragmentation 301_BD_W2k3_05.qxd 5/12/04 12:32 PM Page 154 Defragmentation Best Practices As discussed, defragmenting your disks is a good thing. It speeds up access to your files and can make more free space available. However, for best results, here is a summary of the guidelines to follow when defragmenting your servers: ■ Make sure that you have at least 15 percent of your volume’s total space free. Disk Defragmenter needs to have an area to sort fragments while it is rearranging your volume. If you can’t meet this requirement due to low disk space, you will only get a partial defragmentation. ■ Always try to schedule your defragmentations during non-production hours.You don’t want your users accessing files while the volume is being defragmented.This can cause two problems: users’ performance will suffer because of the resources being consumed by Disk Defragmenter and your defragmentation will take longer. ■ Always analyze before you defragment to make sure that you actually need to.You should analyze any time a large number of files are added to your server or after installing soft- ware on your server. Both of these actions tend to cause high levels of fragmentation. Configuring and Monitoring Disk Quotas The capability to set disk quotas is a feature that was on the “wish list” of Windows NT administra- tors for a long time. Users tend to find a way of consuming every bit (and byte) of space that you offer them.Third-party products provided for setting quotas with NT, and built-in support for disk quotas was first introduced in Windows 2000. Disk quota support has been carried over to Windows XP and Windows Server 2003. In the following sections, we discuss how to enable, con- figure, and monitor disk quotas. Brief Overview of Disk Quotas Disk quotas enable you to track and limit disk space usage on NTFS volumes.You can use disk quotas for two purposes: ■ To audit how much space your users are using (enabling quotas without limiting disk space) ■ To limit your users to a set amount of space (enabling quotas and setting limits on disk space) Users are warned when they approach the specified limit.The administrator can set the level at which the warning occurs. After the limit is reached, a user can no longer save data to the volume without first deleting some files to create new space.You can also set the system to log an event to the event log when a user reaches either the warning level or the disk space limit. Disk quota amounts are calculated based on file ownership.The size of the file is charged against its owner’s limit.The only time this poses a problem is when users share single files. For example, if you have the correct permissions, you can write to a file that someone else owns and it would count against the other user’s limit. Managing Physical and Logical Disks • Chapter 5 155 301_BD_W2k3_05.qxd 5/12/04 12:32 PM Page 155 . the console tree in the left pane and the details pane on the right. On the right side, the pane is split into a top and a bottom section .The top section shows the volumes and partitions on the. typical day on the typical server. Users save data to their home directories. They send e-mail back and forth (which is saved in a database on the server) .They print docu- ments.They access shared. examining these bars, you can see the status of the disk before the defragmentation and the changes that have occurred afterward.These bars are obviously too small to list every cluster on the disk,