Troubleshooting Disks and Volumes

If a disk or volume fails, naturally you want to repair it as soon as possible to avoid losing data. The Disk Management snap-in makes it easy to locate problems quickly. In the Status column of the list view, you can view the status of a disk or volume. The status also appears in the graphical view of each disk or volume.

Diagnosing Problems
To diagnose disk and/or volume problems, perform the following steps:

1.  Open Add Hardware in the Control Panel. Click Next. Windows XP tries to detect new Plug and Play devices.
2.  Click Yes, I Have Already Connected the Hardware, and then click Next.
3.  Choose the device you want to diagnose and fix, and then click Next.
4.  The wizard will inform you of the device’s current status. Click Finish to invoke the Hardware Troubleshooter as part of the Help and Support Center, or click Cancel to exit the Add Hardware Wizard.

Another way to troubleshoot hardware problems is with Device Manager. Right-click the My Computer icon and select Properties. Click the Hardware tab and then click the Device Manager button. Expand the hardware category that you need to troubleshoot and right-click the device that you want to inquire about. Select Properties from the context menu to display the Properties dialog box for that device. All the pertinent information about the device is available from this window, including its device status as determined by the operating system.

Monitoring Disk Performance
The Windows XP performance monitoring tool is composed of two parts: System Monitor and Performance Logs and Alerts. The MMC snap-in is named Performance. With System Monitor, you can collect and view real-time data about disk performance and activity in graph, histogram, or report form. Performance Logs and Alerts enables you to configure logs to record performance data and to set system alerts to notify you when a specified counter’s value is above or below a defined threshold.

To open Performance, perform the following steps:
1.  Click Start, Control Panel.
2.  In the Control Panel, double-click Administrative Tools, and then double-click Performance. You will use System Monitor within Performance to monitor disk activity.

The Diskperf.exe command-line tool was used to control the types of physical and logical disk counters that you could enable for monitoring system performance under earlier versions of Windows. Under Windows XP, disk performance counters are permanently enabled and the Logical Disk object counters have been removed. Instead of using the Logica lDisk object counters for measuring disk performance, Windows XP maps physical drives to logical drives by applying the same instance name. For example, if a computer contains a dynamic volume that is composed of two physical hard disks, the logical drives might appear as Disk 0 C: and Disk 1 C:, which denotes that drive C spans physical disks 0 and 1. For a PC that has three logical volumes on one physical disk, the instance would appear as Disk 0 C: D: E:.

Detecting and Repairing Disk Errors
In previous Windows operating systems, ScanDisk detected and fixed disk errors. In Windows XP, you can use the Error-Checking tool to check for file system errors and bad sectors on your hard disk.

To run the Error-Checking tool, perform the following steps:
1.  Open My Computer and right-click the local disk you want to check.
2.  Select Properties.
3.  Click the Tools tab.
4.  Under Error-Checking, click Check Now.
5.  Under Check Disk Options, select the Scan for and Attempt Recovery of Bad Sectors check box and click Start.

All files must be closed for the Error-Checking process to run. Your volume is not available to run any other tasks while this process is running. If the volume is currently in use, a message asks if you want to reschedule the disk checking for the next time you restart your system. Then, the next time you restart your system, disk-checking runs. If your volume is formatted as NTFS, Windows XP automatically logs all file transactions, replaces bad clusters automatically, and stores copies of key information for all files on the NTFS volume.

You should also be aware of two valuable command-line utilities for troubleshooting and repairing disk problems chkdsk and chkntfs. The chkdsk tool looks for errors on the disk drive that you specify and it can also attempt to repair the errors that it finds. The chkntfs utility displays and can modify which disk drives are marked as “to be checked” at the time of the next reboot. Obviously, chkntfs works only on drive letters, partitions, and volumes formatted as NTFS.

The Disk Defragmenter Tool
Disk Defragmenter rearranges files, programs, and unused space on your computer’s hard disk(s), allowing programs to run faster and files to open more quickly. Putting the pieces of files and programs in a more contiguous arrangement on disk reduces the time the operating system needs to access requested items.

To run Disk Defragmenter, perform the following steps:
1.  Click Start, (All) Programs, Accessories, System Tools, and then click Disk Defragmenter. Alternatively, you can right-click a drive letter in My Computer, select Properties, click the Tools tab, and click Defragment Now.
2.  Select which disk(s) you would like to defragment and any additional options you would like to set.
3.  Click the Defragment button to start the defragmentation process.

Windows XP Professional ships with a command-line version of the disk defragmenter defrag.exe. You can run this program within a batch file or inside of a Windows script, which in turn can be scheduled to run automatically using the Scheduled Tasks folder.

Understanding Why Files Are Not Moved to the Beginning of NTFS Partitions and Volumes
On NTFS-formatted drives, Windows XP reserves a portion of the free space for a system file called the master file table (MFT). The MFT is where Windows stores all the information it needs to retrieve files from the partition or volume. Windows stores part of the MFT at the beginning of the partition or volume. Windows reserves the MFT for exclusive use, so Disk Defragmenter cannot and does not move files to the beginning of partitions and volumes.

Using the Disk Cleanup Wizard
Disk Cleanup helps free up space on your hard drive by searching your drive(s) and then showing you a list of temporary files, Internet cache files, and potentially unnecessary program files that you can safely delete. You can instruct Disk Cleanup to delete none, some, or all of those files.

To use the Disk Cleanup Wizard, perform the following steps:
1.  Click Start, (All) Programs, Accessories, System Tools.
2.  Click the Disk Cleanup icon and follow the onscreen instructions.