barcode vb.net free Disk Defragmenter in Visual C#.NET

Make Code 39 Extended in Visual C#.NET Disk Defragmenter

Files are stored on a volume in units called clusters. Cluster size is configured when formatting a drive; many NTFS volumes use a default cluster size of 4 KB. Each cluster can contain only one file, even if that file is smaller than the cluster size. If a file is larger than the cluster size, the file is saved to multiple clusters, with each cluster containing a pointer to the next segment of the file. When a drive is new, all clusters are free, so as files are written to the drive, they tend to occupy physically adjacent clusters. But quickly, as files are deleted or expanded and contracted in size, free clusters are no longer completely contiguous, so a file might be saved to several clusters that are not physically close to each other on the disk drive. This fragmentation of a file results in slower read and write performance and, over time, fragmentation of multiple files on a server can degrade performance significantly. Windows Server 2003 provides a defragmenter toolset both a command-line and a graphical utility with which volumes can be analyzed and defragmented. The tools

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are significantly improved over Windows 2000 because they can now defragment volumes with cluster sizes greater than 4 KB, and can defragment the master file table. You can use the tools to defragment any local disk volume. But to schedule defragmentation, or to defragment a remote volume, you must look for a third-party tool such as Diskeeper from Executive Software. To use the built-in Disk Defragmenter, shown in Figure 11-5, open the properties of a disk volume and, from the Tools tab, click Defragment Now. Alternatively, open the Disk Defragmenter snap-in in the Computer Management console or a custom Microsoft Management Console. Select a volume and click Analyze. The tool will display a recommendation. If the tool indicates that the volume is dirty, there might be corruption, and Chkdsk should be run before defragmenting.

Figure 11-5

If the recommendation is to defragment, click Defragment. You can defragment any type of volume: FAT or NTFS, basic or dynamic. The volume can have open files, but open files might not be efficiently defragmented and might slow the process, so it is recommended to close all open files before defragmenting. Disk Defragmenter will move files around the drive in an attempt to collect all clusters of a file into contiguous clusters. The result will also consolidate free space, making it less likely that new files will be fragmented.

To completely defragment a volume, the volume should have at least 15 percent free space. This space is used to stage files as they are defragmented. If the volume contains numerous fragmented large files, the amount of free space required for effective defragmentation will be larger.

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Windows 2000 introduced quota management as a built-in feature, allowing administrators to implement storage limits without an investment in third-party utilities. Windows Server 2003 supports the same functionality. When quotas are enabled, quota manager tracks the files on a volume that are owned by a user. It then compares the calculated total of disk usage by that user to limits that have been configured by an administrator and, when those limits are reached, notifies the user that the volume is near quota, prevents the user from writing to the disk, or both. Quota manager reports the amount of free space on a volume based on the user s quota, so if a user has a 50-MB quota on a 500-GB RAID volume, the user will see free space reported as 50 MB when the user first accesses the volume. When the user approaches the quota limit, the messages that appear are similar to a volume that is filling up or is full; the system warns that space is low and suggests deleting unneeded files.