Administrator Guide HP Write Manager

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HP Write Manager

 

©Copyright 2017–2019 HP Development Company, L.P.

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trademarks or trademarks of Microsoft

Corporation in the United States and/or other

countries.

Confidential computer software. Valid license

from HP required for possession, use or

copying. Consistent with FAR 12.211 and

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Technical Data for Commercial Items are

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standard commercial license.

The information contained herein is subject to

change without notice. The only warranties for

HP products and services are set forth in the

express warranty statements accompanying

such products and services. Nothing herein

should be construed as constituting an

additional warranty. HP shall not be liable for

technical or editorial errors or omissions

contained herein.

Third Edition: August 2019

First Edition: June 2017

Document Part Number: 941654-003

 

User input syntax key

Text that you must enter into a user interface is indicated by fixed-width font.

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Item

Description

Text without brackets or braces

Items you must type exactly as shown

<Text inside angle brackets>

A placeholder for a value you must provide; omit the brackets

[Text inside square brackets]

Optional items; omit the brackets

{Text inside braces}

A set of items from which you must choose only one; omit the braces

|

A separator for items from which you must choose only one; omit the vertical bar

Items that can or must repeat; omit the ellipsis

iii

 

iv  User input syntax key

 

image3Table of contents

1 HP Write Manager  1

HP Write Manager minimum requirements for installation  1

HP Write Manager management overview  2

Notification icon  2

HP Write Manager Configuration  3

Command-line arguments  3

Increase the default maximum limit for overlay  3

Making permanent system configurations  4

Disabling or enabling HP Write Manager  4

Configuring a marker  4

Adding a profile  5

Adding cached items to profile  6

Adding files and folders to the file exclusion list  6

Adding a registry key to the registry exclusion list  8

Tips and limitations  8

2 HP Disk Cache  10

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1image4HP Write Manager

HP Write Manager protects the contents of and decreases wear on the flash drive of a thin client by redirecting and caching writes in an overlay. An overlay is a virtual storage space in RAM that tracks changes to a protected volume (that is, the flash drive). The user experience in Windows is unaffected because the operating system maintains the appearance of writing to the flash drive. When a system restart occurs, the overlay cache is cleared, and any changes made since the last system startup are lost permanently.

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image6 NOTE: If it is necessary to make permanent system configuration changes, an administrator can temporarily disable the write filter. In some cases, such as when installing a Windows update, HP Write Manager must be disabled first. See Making permanent system configurations on page 4 for more information.

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image8image9 NOTE: The overlay cache is cleared only by a system restart, so users can log out or switch between user accounts without losing the cached information.

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HP Write Manager allows you to exclude files, folders, and registry settings from protection so that changes are always written directly to the flash drive.

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image13 IMPORTANT:  HP highly recommends the following:

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Ensure that the write filter is used properly for use cases similar to standard thin clients. Proper usage includes making sure the write filter is enabled during end-user (nonadministrator) operation and is disabled only temporarily by an administrator needing to make changes to the system. The write filter should be re-enabled as soon as the changes are completed.
Never enable the Windows Page File feature.
For use cases that require frequent writes, such as active system logging, call center phone and video recording, and industrial logging, you should configure the thin client to write to a server. If local writes are necessary, they should be done in the overlay cache. Please contact HP for help determining an appropriate interval schedule for committing the overlay cache, or preferably log the data from the overlay cache to a server.
Use the purge feature to define rules to remove files from the overlay.

If your use case requires nonstandard write filter usage, please contact HP to ensure that your computers are configured properly.

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HP Write Manager minimum requirements for installation

The system must meet the following perquisites for installation of HP Write Manager:

.Net Framework version 4.5 or later must be installed.
If installing onto Windows 7 Service Pack 1 the following updates must be installed:

KB3033929: Security Update to add SHA-2 code signing support

KB3080149: Update for customer experience and diagnostic telemetry

To download the required updates, please go to https://www.microsoft.com and type the KB number in the search box.

HP Write Manager minimum requirements for installation  1

 

HP Write Manager management overview

You can use two tools to manage HP Write Manager: a notification icon and a Control Panel app. Some commands can be performed using either of the tools, but other commands might be exclusive to one or the other.

Notification icon

The HP Write Manager notification icon is located in the Windows notification area. The following commands can be executed by right-clicking the notification icon and selecting the desired option:

Enable HPWF—Enables HP Write Manager (requires a system restart)
Disable write filter—Disables HP Write Manager (requires a system restart)

The following table describes the possible states of the HP Write Manager notification icon.

Table 1-1 Identifying HP Write Manager notification icons

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Icon  Description

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HP Write Manager is enabled, and no boot command is set.

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HP Write Manager will be disabled (requires a system restart).

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HP Write Manager is disabled, and no boot command is set.

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HP Write Manager will be enabled (requires a system restart).

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The memory usage of the HP Write Manager overlay cache has reached a warning level.

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The memory usage of the HP Write Manager overlay cache has reached a warning level, and HP Write Manager will be disabled (requires a system restart).

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The memory usage of the HP Write Manager overlay cache has reached a critical level.

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The memory usage of the HP Write Manager overlay cache has reached a critical level, and HP Write Manager will be disabled (requires a system restart).

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HP Write Manager is corrupted.

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2Chapter 1 HP Write Manager

 

HP Write Manager Configuration

HP Write Manager Configuration is a Control Panel app for managing HP Write Manager. When used with a thin client operating system, HP Write Manager Configuration can also configure Enhanced Write Filter, File-Based Write Filter, and Unified Write Filter. To open this app:

Double-click the notification icon.

– or –

In Control Panel, select HP Write Manager Configuration.

The tasks you can perform in this app include the following:

Disable or enable HP Write Manager (requires a system restart)
View information about HP Write Manager and the overlay cache
Configure file and registry exclusion settings
Enable or disable HP Disk Cache settings

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image37 NOTE:  For more information about HP Disk Cache settings, go to HP Disk Cache on page 10.

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Edit the exclusion list to add or remove files and folders (requires a system restart)
Set the overlay cache size (requires a system restart)
Set the cache usage in MB at which warning and critical messages each display

Command-line arguments

You can use command-line arguments to manage HP Write Filter. For more information about the command-line arguments, see the HP Write Manager WMI Scripts white paper.

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image41 NOTE:  This white paper is available only in English.

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Increase the default maximum limit for overlay

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image45 IMPORTANT: By default, the maximum overlay is based on how much memory is available on the system that HP Write Manager is installed onto. Changing the maximum limit for an overlay should only be performed by administrators with experience and knowledge of the specifications and configuration of the system being used. Before making any changes, it is recommended to test image performance to determine the appropriate memory required. Do not increase the maximum overlay limit to a number higher than available system memory.

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Follow the procedure below to increase the maximum size allowed for overlay.

1.In the HP Write Manager configuration menu, select More Settings
2.Select the Advanced tab.
3.Input the desired maximum overlay size (in MB) in the entry field. Select OK to save the change.
4.Restart your system for the change to take effect.

Increase the default maximum limit for overlay  3

 

Method 2

Use the HP Write Manager Configuration app to add files or folders to the exclusion list, and then restart the thin client.

Making permanent system configurations

The following table describes the possible methods for making permanent system configurations.

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IMPORTANT:  HP strongly recommends using method 1 in most situations.

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Table 1-2 Methods for making permanent systems configurations

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Method 1

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1.  Disable HP Write Manager (requires a system restart).

2.Make the necessary configurations.
3.Enable HP Write Manager (requires a system restart).

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See the following sections for more information about performing these tasks:

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Disabling or enabling HP Write Manager

The following table describes the possible methods for disabling or enabling HP Write Manager.

Table 1-3 Methods for disabling or enabling HP Write Manager

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Method 1

Method 2

1.

Right-click the notification icon and select the desired state.

1.

Open the HP Write Manager Configuration app.

2.

Restart the thin client.

2.

Select an option to set the desired state.

3.

Restart the thin client.

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TIP:  Method 1 is the quickest way to disable or enable HP Write Manager.

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Configuring a marker

Markers can be used to trigger a purge, which removes files from the overlay.

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image59 NOTE: The event is triggered when the available overlay size is equal to or more than the specified marker size.

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When the Warning marker is reached, a warning message is displayed. When the Critical marker is reached, a countdown to a Windows restart is displayed.

To configure the markers:

1.Open the HP Write Manager Configuration app, and select More Settings.
2.In the Markers tab, set the size (in MB) of the Warning and Critical markers. Overlay size is also displayed, but size can not be modified while in the Markers tab. To modify overlay size, see Increase the default maximum limit for overlay on page 3.
4Chapter 1 HP Write Manager
3.Select OK.
4.Restart the thin client.

 

Adding a profile

A profile is a set of file exclusions, registry exclusions, and options to purge files to ensure that there is available space in the overlay. Profile setting options include the following:

File Exclusion: Files specified in this category will be excluded from the overlay.
Registry Exclusion: Registries specified in this category will be excluded from the overlay.
Purge on Marker: HP Write Filter will delete files specified in this category from the overlay when overlay usage reaches defined marker settings.
Purge on App Exit: HP Write Filter will delete files specified in this category from the overlay when the specified app is exited.
Purge Exclusion: HP Write Filter will exclude files listed in this category from being deleted.

To add a profile:

1.Open the HP Write Manager Configuration app, and select More Settings.
2.In the Profiles tab, select Add.
3.Enter a name in the Profile name box.
4.In the File Exclusion tab, select the Add folder button or the Add file button to add an item to the exclusion list. Repeat as necessary.

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image63 NOTE: When a folder is added for exclusion, all files in that folder, including every subfolder under that folder, will also be excluded.

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5.In the Registry Exclusion tab, select the Add button to add an item to the exclusion list. Repeat as necessary.
6.In the Purge on Marker tab, select the Add button to add an item to be purged when a marker is reached. Repeat as necessary.
7.In the window that opens, do the following:
a.Enter the path to the file to be purged in the File path box.
b.Under Start On, select which marker determines when HP Write Manager starts to purge the files.
c.Under Stop On, select which marker must be reached to stop the purge.
d.Optionally, edit the Application path to specify which application is associated with the files listed under File path. This limits the files purged within the File path to those associated with the application.
e.Select OK.
8.In the Purge on App Exit tab, select the Add button to add an item to be purged when an app is closed. Repeat as necessary.
9.In the window that opens, enter the File path for the file to be purged, select the Application path for application that starts a purge when closed, and then select OK.
10.In the Purge Exclusion tab, select the Add button to add an item to excluded from a purge. Repeat as necessary.

Making permanent system configurations  5

11.In the window that opens, enter the File path, and then select OK.
12.Select OK.
13.Restart the thin client.

 

To enable or disable an existing profile, select the desired state next to the Profile name.

To edit an existing profile, select the Edit icon.

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image67image68 NOTE:  HP Write Manager comes with various default profiles named after their suggested usage scenario.

These profiles can be further customized by following the procedures outlined above.

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Adding cached items to profile

You can add any cached item in the overlay to existing and new profiles or file exclusion.

1.In the HP Write Manager Configuration menu, select More Settings.
2.Select the Overlay tab.
3.If no items are listed, select Refresh.

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TIP:  HP Write Manager must be enabled to refresh this tab.

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4.Select the item. To select multiple items, press ctrl while selecting.
5.Select Add to add the selected items.

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TIP: Overlay features can be sorted by application, file path, file size, or username. Select the content categories from the top of the dialog box.

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The content categories File path, Process, User, and Profile name can be sorted in either ascending or descending alphabetical order.

The content categories File size and Overlay size can be sorted according to ascending or descending size.

You can determine how much memory a new application uses by viewing the application files in the overlay.

Items listed in green are items that have been added to a profile since the computer was last started.

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Adding files and folders to the file exclusion list

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image77 IMPORTANT: Changes to items in the exclusion list are always written directly to the flash drive; so keep the exclusion list to a minimum.

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1.Open the HP Write Manager Configuration app, and select More Settings.
2.On the File Exclusion tab, select the Add folder button or the Add file button to add an item to the exclusion list. Repeat as necessary.

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image81 NOTE:  Items can be removed from the exclusion list using the Delete button.

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3.Select OK.
4.Restart the thin client.

The following table describes the highlight colors used for the exclusion list in the HP Write Manager Configuration app.

6Chapter 1 HP Write Manager

Table 1-4 Identifying exclusion list highlight colors for the HP Write Manager Configuration app

 

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Color

Description

None

The item is excluded.

Green

The item will be added to the exclusion list (requires a system restart).

Red

The item will be removed from the exclusion list (requires a system restart).

Making permanent system configurations  7

 

Adding a registry key to the registry exclusion list

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image86 IMPORTANT: Changes to items in the exclusion list are always written directly to the flash drive; so keep the exclusion list to a minimum.

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1.Open the HP Write Manager Configuration app, and select More Settings.
2.In the Registry Exclusion tab, select the Add button to add an item to the exclusion list. Repeat as necessary.

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image90 NOTE:  Items can be removed from the exclusion list using the Delete button.

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3.Select OK.
4.Restart the thin client.

The following table describes the highlight colors used for the exclusion list in the HP Write Manager Configuration app.

Table 1-5 Identifying exclusion list highlight colors for the HP Write Manager Configuration app

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Color

Description

None

The item is excluded.

Green

The item will be added to the exclusion list (requires a system restart).

Red

The item will be removed from the exclusion list (requires a system restart).

Tips and limitations

Use the following tips for optimal performance of HP Write Manager.

When HP Write Manager is enabled on an HP computer, the RAM drive is disabled. All temporary files are stored in the c:\HPWMTemp folder. Any variables originally pointing to drive Z are redirected to c: \HPWMTemp folder.

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image95 NOTE: When HP Write Manager is enabled, the disabled RAM drive appears as a disabled device in Device Manager.

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Do not add the disk C root directory (that is, C:\) to a file path in the file exclusion list.
The following characters cannot be used in the file path for the file exclusion list: [email protected]#$%^&*()_+=-`[];’,./{}|:”<>?”
If there is a space in the file path of a key to be added to a registry exclusion list, be sure to enclose the path in straight quotes (that is, “).
HKEY_LOCAL_MACHINE\HARDWARE cannot be added to the registry exclusion list.
If you are adding registry keys to the registry exclusion list, HP Write Manager can translate some input to the proper form, such as – HKLM to \REGISTRY\MACHINE. If you are using WMI, the explicit name of the registry key must be used.
The wildcard * is allowed in registry paths and represents any folder or no folder in the previous directory element in the path. It can only represent a single directory element.
If the overlay cache reaches a critical level, the system might become unstable. You can change the critical level setting or create a profile to help limit the size of the cache by purging unnecessary files.
8Chapter 1 HP Write Manager

 

image98TIP:  If the Start menu is not responding properly, use ctrl+alt+delete to restart the computer.

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You must disable the write filter (which requires a system restart) before switching to a different write filter.
If you enable the write filter and then enable Global Bypass Mode, only those registry keys created after Global Bypass Mode is enabled will persist. If you rename a registry key created when only the write filter was enabled, it will not persist. You must create it again.

Tips and limitations  9

2image101HP Disk Cache

HP Disk Cache consolidates the write requests from the operating system to reduce the number of writes made to the flash drive. This extends the usable life of the flash drive.

To enable HP Disk Cache:

1.In the HP Write Manager Configuration app, select Advanced Cache Settings.
2.Set HP Disk Cache to On.
3.Enter values for the Cache size, Flush count, and Flush interval.

– or –

Select Reset to Defaults.

 

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image103 NOTE: HP has optimized these settings to provide the maximum benefit in terms of system performance and disk longevity.

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Flush count—Sets the number of disk write requests from the operating system to be consolidated by HP Disk Cache before completing the requests (unless the flush interval is reached first). This reduces the number of writes to the flash drive, but it might cause issues if a sudden power loss occurs when a high number of requests have been stored.
Flush interval—Sets the amount of time during which HP Disk Cache consolidates disk write requests from the operating system before completing the requests (unless the flush count is reached first). This reduces the number of writes to the flash drive, but it might cause issues if a sudden power loss occurs when a high number of requests have been stored.

10  Chapter 2 HP Disk Cache

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