Time-out errors occur in Volume Shadow Copy service writers
Sometimes, during the backup process, some Volume Shadow Copy
service writers might fail because of time-out errors that cause the backup to
fail. A Volume Shadow Copy service writer is a program or a service that uses
Volume Shadow Copy service to save information to a shadow copy storage area.
For example, when you use the NTBackup program, the backup may not be
successful, and you may receive the following error message:
Error returned while creating the volume shadow copy:
800423f4 (or the values 800423f2 or 800423f3)
To diagnose the Volume
Shadow Copy service writer problem, run the vssadmin command immediately after the backup failure:
Click Start, and then click
Type vssadmin list
This command lists the Volume Shadow Copy service writers and
the current state of each writer. For example, the output might indicate that
the Microsoft SQL Server Desktop Engine (MSDE) or the Microsoft Active
Directory directory service writer failed. You may experience time-out errors
on several writers, including the MSDE writer, the SQL writer, the New
Technology Directory Service (NTDS) writer, the Windows Internet naming system
(WINS) writer, the Dynamic Host Configuration Protocol (DHCP) writer, the
Remote Storage writer, the certification authority writer, and the Microsoft
Exchange writer. The following is sample output:
You may experience a problem that causes certain Volume Shadow
Copy service writers to time out during a lengthy shadow copy creation. This
problem occurs especially on computers that have slow hard disks, low memory,
or low CPU speed; or on computers that have the disk write cache disabled (for
example, on a domain controller computer).
Shadow copy creation
includes a complex sequence of inter-process calls. The inter-process calls
make sure that all the important Volume Shadow Copy service writers (programs
such as SQL, Exchange Server, operating system services, and others) flush
their data buffers during shadow copy creation. Also, some Volume Shadow Copy
service writers, like the Exchange writer, wait to write for a predefined time
interval so the shadow copy can be created during the time interval. The
writers wait to write so the contents of the shadow copy will be consistent
with their data buffers. However, if there is low CPU speed, high memory usage,
or high input/output levels, you may experience the following behaviors:
The writers do not flush their data buffers.
The writers do not wait the time interval before they
When this problem occurs, shadow copy creation fails.
Important Volume Shadow Copy service writers may fail with similar errors
because of other conditions. These conditions include a lack of disk space or
improper configuration of the computer. This hotfix addresses only the specific
timeout errors that might randomly occur in Volume Shadow Copy service writers
during backup. You are strongly advised to review the event log for any other
potential Volume Shadow Copy service errors that might generate a writer
You may also experience a problem in the Volsnap.sys driver that
causes shadow copy deletion when there is a high level of input/output,
especially when the disk write cache is disabled (for example, on a domain
By default, the shadow copy provider that is
included in Microsoft Windows Server 2003 is used to create shadow copies for
backup purposes. The shadow copies are implemented by using a copy-on-write
implementation. The differences are also copied in the shadow copy storage
area. In Volume Shadow Copy service, you can use the shadow copy management
tool, or you can use the vssadmin command.
In the original released version of Windows
Server 2003, the initial shadow copy storage area that is allocated for shadow
copy creation is 100 megabytes (MB). However, the actual space that is used is
much smaller. As time passes, the allocated space may increase as more data is
modified on the original volume. However, when you have high input/output
traffic on the original volume, the shadow copy storage area cannot grow fast
enough to hold all the copy-on-write changes. This causes deletion of all the
shadow copies on the original volume. This problem is more noticeable in domain
controller configurations. By default, the disk write cache is disabled in
domain controller configurations.
Important A similar problem is caused by defragmenting a volume with small
cluster size, where all shadow copies are deleted, and where the event log
error that is listed earlier in this article is logged. For
additional information about losing shadow copies during a disk
defragmentation, click the following article number to view the article in the
Microsoft Knowledge Base:
Shadow copies may be lost when you defragment a volume
Also, event error ID 2004 may be logged when there
are corrupted NTFS file system volumes. To determine if this is the problem,
run the Chkdsk.exe program with the /f switch.
To resolve this problem, obtain the
latest service pack for Windows Server 2003. For more information, click the
following article number to view the article in the Microsoft Knowledge Base:
How to obtain the latest service pack for Windows Server 2003
A supported hotfix is available from Microsoft. However, this
hotfix is intended to correct only the problem that is described in this
article. Apply this hotfix only to systems that are experiencing this specific
problem. This hotfix might receive additional testing. Therefore, if you are
not severely affected by this problem, we recommend that you wait for the next
software update that contains this hotfix.
If the hotfix is available
for download, there is a "Hotfix download available" section at the top of this
Knowledge Base article. If this section does not appear, contact Microsoft
Customer Service and Support to obtain the hotfix.
Note If additional issues occur or if any troubleshooting is required,
you might have to create a separate service request. The usual support costs
will apply to additional support questions and issues that do not qualify for
this specific hotfix. For a complete list of Microsoft Customer Service and
Support telephone numbers or to create a separate service request, visit the
following Microsoft Web site:
Note The "Hotfix download available" form displays the languages for
which the hotfix is available. If you do not see your language, it is because a
hotfix is not available for that language.
No prerequisites are required.
You must restart your computer after you apply this hotfix.
Hotfix replacement information
This hotfix does not replace any other hotfixes.
The English version of this hotfix has the file
attributes (or later file attributes) that are listed in the following table.
The dates and times for these files are listed in Coordinated Universal Time
(UTC). When you view the file information, it is converted to local time. To
find the difference between UTC and local time, use the Time
Zone tab in the Date and Time item in Control Panel.
Windows Server 2003, Microsoft Windows Small Business Server 2003
Important This section, method, or task contains steps that tell you how to
modify the registry. However, serious problems might occur if you modify the
registry incorrectly. Therefore, make sure that you follow these steps
carefully. For added protection, back up the registry before you modify it.
Then, you can restore the registry if a problem occurs. For more information
about how to back up and restore the registry, click the following article
number to view the article in the Microsoft Knowledge Base:
How to back up and restore the registry in Windows
This hotfix makes some classes of writer
(SQL, Active Directory, and others) less likely to experience time-out errors.
In part, this hotfix is designed to improve the performance of the default
shadow copy driver (Volsnap.sys) when there are high input/output levels. The
hotfix also includes a larger initial size for the shadow copy storage area:
300 MB instead of 100 MB. Additionally, if a 300 MB initial size is not
sufficient, and if shadow copies are still lost because of high input/output
levels, this hotfix includes a way for you to configure the initial size of the
shadow copy storage area when the shadow copy storage area is created. You can
configure the initial size of the shadow copy storage area by using the
configurable registry key setting that this hotfix provides.
these steps, and then quit Registry Editor:
Click Start, click Run,
type regedit, and then click OK.
Locate and then click the following key in the registry:
On the Edit menu, point to
New, and then click DWORD value.
Type MinDiffAreaFileSize, and then
On the Edit menu, click
Type the size that you want for the shadow copy storage
area, and then click OK.
The MinDiffAreaFileSize registry key
specifies the minimum size of the shadow copy storage area; the default setting
is 300 MB, and the maximum setting is 3 gigabytes (GB). For an accurate
setting, specify a value that is a multiple of 300 MB; otherwise, the next
multiple of 300 MB will be chosen. A value of 300 is equal to 300 MB, and a
value of 3,000 is equal to 3 GB.
Note Shadow copies may not function correctly if the value of the
MinDiffAreaFileSize registry subkey is larger than the maximum size of the
shadow copy storage area. For example, if you set the registry setting to
1024 MB, backup software will not generate snapshots of the 200 MB
system partition. Therefore, before you create the MinDiffAreaFileSize registry
subkey, make sure that the diff area file is
larger than 300 MB or that the diff area file is larger than the value that is specified in the registry.
Also, make sure that you have at least 300 MB of free space on the shadow copy