Sams Teach Yourself MCSE Windows NT Server 4 in 14 Days
(Publisher: Macmillan Computer Publishing)
Author(s): David Schaer, et al
ISBN: 0672311283
Publication Date: 12/15/97

The partition does not have to utilize the entire amount of free space available as shown in Figure 5.20, although it can. The maximum size of the partition will be governed by the amount of free space available on a given disk.

The maximum size of a single partition theoretically is 2TB.

Figure 5.20.  Selecting the size of the new partition.

In Figure 5.20 the administrator has selected to create a primary partition of 150MB. The partition is assigned a drive letter; however, the file system type will be unknown until the partition is formatted. After the partition has been formatted it is commonly referred to as a volume.

Before formatting the partition the administrator must commit the changes to the disk configuration. The option to commit the changes immediately is shown in Figure 5.21. After the administrator has committed to the changes simply canceling from the program cannot reverse them. If changes are made and not committed, then quitting the Disk Administrator returns the system to its original configuration.

Figure 5.21.  The option to commit changes now.

After the changes have been committed the administrator can format the partition by selecting the Format option under Tools. The partition can be formatted as either FAT or NTFS from the command prompt or through the Disk Administrator as shown in Figure 5.22.

Figure 5.22.  Formatting the new partition as an NTFS volume.

Although formatting from the Disk Administrator is more convenient, formatting from the command prompt enables the administrator to select cluster sizes greater than 4KB to be specified for the volume. The Disk Administrator limits the allocation unit size to 4KB because this is the maximum size cluster that can be used with NTFS compression. From the command prompt the cluster, or allocation unit, size can be set from 512 bytes to 64KB for NTFS. FAT can support clusters up to 256KB.

A volume on which you plan to hold mainly large database files would benefit from a large cluster size.

The drive letter automatically assigned the volume can be changed through the Disk Administrator. In Figure 5.22 the volume was assigned drive letter F. The administrator can change the drive letter assignment to any available letter. In Figure 5.23 the drive letter is modified to be drive X.

Figure 5.23.  Modifying the drive letter through the Disk Administrator.

Changing the drive letter associated with a volume or CD-ROM takes effect immediately if no program is accessing the drive.

5.7.2. Deleting Partitions

When a partition is deleted all data held on the partition is lost. The Disk Administrator will not enable you to delete the boot or system partition.

If you accidentally delete a partition before the changes have been committed you can cancel out of the Disk Administrator. The drive will still be intact.

5.7.3. Volume Sets

Volume sets are combinations of 2 to 32 segments of disk space from 1 to 32 physical disks. The segments do not have to be identical in size. The collective area forms a volume set that is represented by a single drive letter. The areas used to create the volume set can be from an existing NTFS partition and an area of free space or from separate areas of free space.

In Figure 5.24 the free spaces are selected and the size of the volume set determined (see Figure 5.25). You must restart your computer (Figure 5.26) before you can format the new volume set (Figure 5.27). The volume set is treated as a single partition even though it is composed on noncontiguous sections.

Figure 5.24.  Areas of free space are selected to form a volume set.

Figure 5.25.  The volume set could be as large as the collective areas of free space selected.

Figure 5.26.  You must restart the computer before you reformat the volume set.

Know This: The volume set can be formatted as either FAT or NTFS.

Figure 5.27.  The volume set is formatted as FAT. Either FAT or NTFS can be used as the file system for volume sets.

You can incorporate into the volume set additional areas of free space to increase the total size. The space used can be from the same disk or from any other physical disk in the system. In order to be extended the volume set must have NTFS as its file system as shown in Figure 5.28.

Figure 5.28.  A volume set formatted as FAT cannot be extended.

Only volume sets with the NTFS file system can be extended.

In order to extend a volume set formatted with FAT you must first change the file system to NTFS by either formatting or converting the volume. Converting the file system using the convert program from the command prompt is normally the optimal solution because this will preserve the data on the volume.

Know this: The system and boot partitions cannot be part of a volume set regardless of the file system used.

Volume sets do not provide fault tolerance disk access improvements. Remember that they provide zero redundancy and therefore zero fault tolerance. Volume sets do not increase performance because they do not balance the reads and writes between the areas of space used. The first area of space incorporated into the volume set is filled completely before the next area is written to. If any of the disks containing any part of the volume set fail, the data across the entire volume set is lost. The data can be recovered only from backup.

Volume sets do not increase system performance regardless of how many physical disks are used.

Using volume sets is not a means of establishing fault tolerance.