Limitations of the Shrink Volume feature of Veritas Storage Foundation for Windows
Article ID: 100017918
Updated On:
Resolution
Description
The Shrink Volume feature may be used to decrease the size of a volume without having to recreate it. However,there are two important limitations:
- It cannot be used on a volume that is greater than 2 terabytes (TB) in size.
- It cannot decrease the size of a volume past the location of a cluster that contains data. In some cases, this severely limits the amount by which the size of the volume can be decreased.This is particularly noticeable when data fragmentation has caused data clusters to be scattered toward the end of the volume.
Workaround
Veritas has identified two steps that may increase the amount by which the size of a volume may be decreased.
Note: This workaround does not apply to volumes that are greater than 2 TB in size.
1. Defragment the volume. This may cause data clusters that are located near the end of the volume to be relocated. This allows the volume size to be further decreased.
Warning: Defragmenting a volume may generate a large amount of I/O. To avoid a negative impact on disk performance, schedule the defragmentation operation for a time when the disk usage is low.
2. DiskView, a Microsoft utility, may be used to examine the layout of the data clusters in a volume. In many cases, a defragmentation operation may be unable to move some of the data clusters. In these cases, DiskView may be used to determine which files are associated with the data clusters that are blocking the Shrink Volume operation. Once the file has been identified, the following steps may be used to relocate them:
Warning: This procedure involves a utility that is not written or supported by Veritas. It is recommended that all data on the affected volumes is completely backed up and that a recovery plan is prepared that allows for enough time to perform a full restore in the event of data corruption.
1. Move the file to another volume. The original copy of the file should no longer exist at this point.
2. Defragment the volume
3.Copy or move the file back to the original volume. The data clusters that are associated with the file should now be contiguous with the existing data clusters instead of being scattered toward the end of the volume.
Note:Data that is identified as a "system file cluster" cannot normally be moved. Forfurther assistance with system file clusters, contact Microsoft Technical Support.
The Shrink Volume feature may be used to decrease the size of a volume without having to recreate it. However,there are two important limitations:
- It cannot be used on a volume that is greater than 2 terabytes (TB) in size.
- It cannot decrease the size of a volume past the location of a cluster that contains data. In some cases, this severely limits the amount by which the size of the volume can be decreased.This is particularly noticeable when data fragmentation has caused data clusters to be scattered toward the end of the volume.
Workaround
Veritas has identified two steps that may increase the amount by which the size of a volume may be decreased.
Note: This workaround does not apply to volumes that are greater than 2 TB in size.
1. Defragment the volume. This may cause data clusters that are located near the end of the volume to be relocated. This allows the volume size to be further decreased.
Warning: Defragmenting a volume may generate a large amount of I/O. To avoid a negative impact on disk performance, schedule the defragmentation operation for a time when the disk usage is low.
2. DiskView, a Microsoft utility, may be used to examine the layout of the data clusters in a volume. In many cases, a defragmentation operation may be unable to move some of the data clusters. In these cases, DiskView may be used to determine which files are associated with the data clusters that are blocking the Shrink Volume operation. Once the file has been identified, the following steps may be used to relocate them:
Warning: This procedure involves a utility that is not written or supported by Veritas. It is recommended that all data on the affected volumes is completely backed up and that a recovery plan is prepared that allows for enough time to perform a full restore in the event of data corruption.
1. Move the file to another volume. The original copy of the file should no longer exist at this point.
2. Defragment the volume
3.Copy or move the file back to the original volume. The data clusters that are associated with the file should now be contiguous with the existing data clusters instead of being scattered toward the end of the volume.
Note:Data that is identified as a "system file cluster" cannot normally be moved. Forfurther assistance with system file clusters, contact Microsoft Technical Support.
Issue/Introduction
Limitations of the Shrink Volume feature of Veritas Storage Foundation for Windows
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