Back to Contents Page

Dell ActiveArchive

Dell™ PowerVault™ 715N NAS Appliance System Administrator's Guide

  Introduction to Persistent Images

  Scheduling Persistent Images

  Using Persistent Images

  Accessing Stored Persistent Images in Dell ActiveArchive

  Restoring Volumes From an Existing Persistent Image

  Changing the Dell ActiveArchive Event Log Language

Dell ActiveArchive™ allows the creation and preservation of persistent images of Dell PowerVault™ 715N system data volumes. The Dell ActiveArchive software is available for all PowerVault 715N systems. It can be configured by using the NAS Manager.

This section provides information about the following topics:

• Introduction to persistent images
  
  
• Scheduling persistent images
  
  
• Adding persistent images to the schedule
  
  
• Deleting a persistent image schedule
  
  
• Editing the properties of a persistent image schedule
  
  
• Taking a new persistent image on demand
  
  
• Deleting a persistent image
  
  
• Undoing writes to a read/write persistent image
  
  
• Configuring the persistent image global settings
  
  
• Setting persistent image retention weights and read only or read/write attributes
  
  
• Accessing store persistent images in Dell ActiveArchive
  
  
• Restoring volumes from an existing persistent image
  
  

Introduction to Persistent Images

A persistent image is a point-in-time copy of a disk volume. Unlike conventional volumes, the information in the persistent image is static. A persistent image contains an exact copy of the file system at the time the persistent image was created. If you change a file on the active file system after taking a persistent image, the persistent image contains the old version of the file. If an active file gets corrupted or deleted, you can restore the old version by copying the file from the latest persistent image. Also, because the persistent image contains the contents of the file system when the persistent image was taken, you can perform a backup from the persistent image without stopping all I/O to the file servers, thus, eliminating the backup window required by other types of backup.

NOTICE: Persistent images are temporary backups of your data that reside on the same volume as your data. If the volume becomes damaged, you lose your data, including the persistent image. Therefore, persistent images do not replace regular backups of your volume.

Cache File

The Dell ActiveArchive software stores changed data in a cache file. A cache file resides on each volume of your system. By default, the persistent image cache file is 20 percent of each volume. You can use the NAS Manager to change the percentage of the volume that is dedicated to the cache file.

NOTE: You cannot take a persistent image of the operating system volumes or the recovery operating system drives (C: or D:).

Cache Thresholds

The Dell ActiveArchive software has two thresholds that provide warnings when the cache file is approaching maximum capacity. The Cache Full Warning Threshold logs an event in the event log and displays an error in the NAS Manager status indicator when the cache file reaches the threshold (default is 80 percent full). The Cache Full Threshold, which is labeled Begin deleting images in the NAS Manager, specifies the threshold where the PowerVault NAS Manager deletes the oldest persistent images with the lowest retention weights until the cache file is below the Cache Full Threshold (default is 90 percent full).

Persistent Image Retention Weights

When the system reaches the cache full threshold, the system starts deleting files, depending on the retention weight and age of the persistent image. The system first looks for the persistent image with the lowest retention weight in the cache file and deletes the oldest persistent image with the retention weight. After all persistent images with the lowest retention weight have been deleted, Dell ActiveArchive looks for and deletes the oldest files with the next higher retention weight.

Persistent Image Considerations

When using persistent images, system performance might be degraded, depending on the rate your data is changing and the number of persistent images kept for each virtual disk. Read performance of the virtual disk remains constant, regardless of the presence of persistent images. Read performance of the persistent image is identical to that of the virtual disk. Write performance, however, might vary. Each initial write to a virtual disk area causes the Dell ActiveArchive software to rewrite the data to the persistent image cache file, and the initial write is slower if the data is being protected by a persistent image. Changes to data that is not protected by a persistent image does not cause a performance degradation.

NOTICE: If you use one of the recovery processes to reinstall your operating system, your persistent images are deleted.

Storing Persistent Images

You can store up to 250 persistent images per volume; however, if you exceed 250 persistent images, the oldest persistent image with the lowest retention weight is overwritten. This number of persistent images allows you to schedule multiple persistent images. (You should tailor your schedule depending on how the data is changing.) For example, you could implement a schedule similar to the following schedule:

• Seven daily persistent images with a high priority
  
  
• Two weekly persistent images with a medium priority
  
  
• Two monthly persistent images with a low priority
  
  

This type of schedule gives you good snapshot coverage and ensures that your most recent data has the highest priority.

Accessing Directories, Folders, and Files

By default, administrators can access the ActiveArchive directory in the root of each volume. Each persistent image is displayed separately with a date and time stamp showing when the persistent image occurred. The administrator can browse the persistent image as if it were a standard volume. Each persistent image is mounted as a volume on the file system to allow access by clients. Persistent images are created as read-only.

Persistent image directories are used in the same way that conventional directories are used. The files and folders in the persistent image directories have the same permissions as the files and folders on the original volume. All persistent images are persistent and survive system power losses or reboots.

NOTE: The ActiveArchive directory is a hidden folder. You must configure your system to view hidden files and folders to view your ActiveArchive directory.

Allowing User Access to Persistent Images

The files and folders within a persistent image are identical to the permissions on the original files and folders. However, by default, the ActiveArchive directory is restricted to administrator access only. To allow users to access the persistent images, the system administrator must modify the permissions for the ActiveArchive directory.

Use the PowerVault NAS Manager to change the ActiveArchive directory permissions by performing the following steps.

NOTE: To use the PowerVault NAS Manager, you must be logged in as administrator. The PowerVault NAS Manager default administrator user name is administrator and the default password is powervault.

1. On the NAS Manager primary menu, click the Maintenance tab.
   
   
2. Click Terminal Services.
   
   
3. Log on to a Terminal Services Advanced Client session.
   
   
4. Open the Windows Explorer.
   
   
5. Select the drive on the left side.
   
   
6. Right-click the ActiveArchive directory, and then click Properties.
   
   
7. Click the Security tab, and then click Add....
   
   
8. Click specific users or groups or type the individual users or group names to add individual users or groups, and then click OK.
   
   
9. Give the selected members Read and List Folder Contents permissions.
   
   
10. Click OK.
    
    

Repeat the steps for the ActiveArchive directory on each volume the users can access. You do not need to change the permissions of the persistent images and their subdirectories. The files and folders retain the original files' and folders' permissions.

Scheduling Persistent Images

When you click Disks—> ActiveArchive—> Schedules, the Scheduled Persistent Image page displays a list of all scheduled persistent images and associated tasks. Each scheduled persistent image is identified by the scheduled time, day, frequency, starting date, and target volume ID. Persistent images are identified by time and date, and are located in the ActiveArchive directory. The ActiveArchive directory is located in the root of each ActiveArchive volume. Only the administrator can access the ActiveArchive directory. The files and folders in the persistent image directories have the same permissions as the files and folders on the original volume. Persistent image directories are used exactly the same as conventional system volumes. Unlike conventional volumes, read-only persistent image images are static, recording the precise content of the originating volume at the time you created the persistent image.

Displaying the List of Persistent Images

The Persistent Images page displays all current active persistent images. Each entry identifies the date and time the persistent image was created and the volume it preserves. Select an individual persistent image by clicking the radio button to the left of the description.

1. On the NAS Manager primary menu, click Disks, and then click ActiveArchive.
   
   
2. Click Persistent Images.
   
   

Adding Persistent Images to the Schedule

1. On the NAS Manager primary menu, click Disks, then click ActiveArchive.
   
   
2. Click Schedules.
   
   
3. In the Tasks list on the Persistent Image Schedules page, click New...
   
   
4. Use the menus to select the Starting time, the frequency at which to repeat the persistent image (Repeat every frequency), the Beginning day, the Volume(s), the Image Attributes (Read-only or Read/Write), the Retention Weight, Number of images (per schedule) to save, and the persistent image Name.
   
   

NOTE: To select multiple volumes, press and hold <Ctrl> and select all volumes that are to be included in the persistent image.

You can use patterns in the persistent image name to differentiate your persistent images. For example if you use a pattern of Snapshot.%i and you take two persistent images, you have Snapshot.1 and Snapshot.2. The default persistent image name pattern is Snapshot %M-%D-%Y %H.%m.%s. Valid pattern macros are as follows:

• %M = Month
  
  
• %D = Day
  
  
• %Y = Year
  
  
• %h = Hours in 12-hour format
  
  
• %H = Hours in 24-hour format
  
  
• %s = Second
  
  
• %i = Instance, which increments once per instance
  
  
• %a = AM/PM
  
  
• %W = Day of the week
  
  
• %w = Three-letter day of the week
  
  
• %% = Percent sign
  
  

5. Click OK to save the new scheduled persistent image.
   
   

Deleting a Persistent Image Schedule

1. On the NAS Manager primary menu, click Disks, and then click ActiveArchive.
   
   
2. Click Schedules.
   
   
3. On the Persistent Image Schedules page, click the check box next to the scheduled persistent image to be deleted.
   
   
4. In the Tasks list on the Persistent Image Schedules page, click Delete.
   
   
5. Click OK to delete the item or Cancel to leave the item intact.
   
   

Editing the Properties of a Persistent Image Schedule

1. On the NAS Manager primary menu, click Disks, and then click ActiveArchive.
   
   
2. Click Schedules.
   
   
3. In the Tasks list on the Persistent Image Schedules page, click Properties...
   
   
4. Use the appropriate menus to select the Starting time, the frequency at which to repeat the persistent image (Repeat every frequency), the Beginning day, the Volume(s), the Image Attributes (Read-only or Read/Write), and the Number of images (per schedule) to save.
   
   

NOTE: To select multiple volumes, press and hold <Ctrl> and select all volumes that are to be included in the persistent image.

5. Click OK to modify the schedule or Cancel to leave the schedule intact.
   
   

Using Persistent Images

In addition to scheduling persistent images, you can take new persistent images on demand, delete existing persistent images, configure the persistent image environment, and set persistent image retention weights.

Taking a New Persistent Image on Demand

1. On the NAS Manager primary menu, click Disks, and then click ActiveArchive.
   
   
2. Click Persistent Images.
   
   
3. In the Tasks list on the Persistent Images page, click New...
   
   
4. In the menu that is displayed, select the Volume(s) to preserve.
   
   

NOTE: To select multiple volumes, press and hold <Ctrl> and select all volumes that are to be included in the persistent image.

5. Select the Read Only or Read/Write attribute.
   
   
6. Select the Retention Weight for the persistent image.
   
   
7. Enter the persistent image name.
   
   

You can use patterns in the persistent image name to differentiate your persistent images. For example if you use a pattern of Snapshot.%i and you take two persistent images, you have Snapshot.1 and Snapshot.2. The default persistent image name pattern is Snapshot %M-%D-%Y %H.%m.%s. Valid pattern macros are as follows:

• %M = Month
  
  
• %D = Day
  
  
• %Y = Year
  
  
• %h = Hours in 12-hour format
  
  
• %H = Hours in 24-hour format
  
  
• %s = Second
  
  
• %i = Instance, which increments once per instance
  
  
• %a = AM/PM
  
  
• %W = Day of the week
  
  
• %w = Three-letter day of the week
  
  
• %% = Percent sign
  
  

8. Click OK to create the persistent image.
   
   

Deleting a Persistent Image

1. On the NAS Manager primary menu, click Disks, and then click ActiveArchive.
   
   
2. Click Persistent Images.
   
   
3. On the Persistent Images page, click the check box next to the persistent image that is to be deleted.
   
   
4. In the Tasks list, click Delete.
   
   
5. Click OK to delete the persistent image.
   
   

Undoing Writes to a Read/Write Persistent Image

To undo writes to a read/write persistent image, you must select an item from the Persistent Images list, and then click Undo in the Tasks list.

To undo persistent image writes, perform the following steps:

1. On the NAS Manager primary menu, click Disks.
   
   
2. Click ActiveArchive, and then click Persistent Images.
   
   
3. On the Persistent Images page, click the radio button next to the persistent image to be restored to its original state.
   
   
4. Click OK to restore the image or Cancel to leave it intact.
   
   

Setting Persistent Image Retention Weights and Read Only or Read/Write Attributes

To change the read only or read/write attribute or the retention weight (deletion priority) of an image, you must edit the persistent image properties by selecting an image from the Persistent Image list, and then clicking Properties in the Tasks list.

To edit the persistent image properties, perform the following steps:

1. On the NAS Manager primary menu, click Disks, and then click Persistent Images.
   
   
2. In the list of persistent images, click the checkbox next to the persistent image you are editing.
   
   
3. In the Task list, click Properties....
   
   
4. Select the Read Only or Read/Write attribute.
   
   
5. Select the Retention weight.
   
   
6. Click OK to update the persistent image.
   
   

Configuring the Persistent Image Global Settings

You can modify the various aspects of the persistent image environment by performing the following steps:

1. On the NAS Manager primary menu, click Disks, and then click ActiveArchive.
   
   
2. Click Global Settings, and then configure the following options.
   
   

NOTE: Before changing the Image Directory Name, you must delete all existing persistent images.

• Maximum Persistent Images — Specifies the maximum number of active persistent images per volume, up to a maximum of 250. When the volume has 250 persistent images stored, starting another persistent image overwrites the oldest persistent image with the lowest retention weight.
  
  
• Inactive Period — Prior to starting a persistent image, the system waits for a period of relative inactivity on the volume being imaged. The default value for this period, which is 5 seconds, allows systems to start an image with a consistent file set and a minimal time-out. Experienced administrators may reduce or increase this value for system optimization. Reducing the inactive period allows persistent images to begin on systems where disk inactivity is rare, at the possible expense of synchronization problems within applications that are concurrently writing to multiple files.
  
  
• Inactive Time-Out — Specifies the amount of time the server continues to retry to create a persistent image (default time is 15 minutes). A persistent image cannot start until a period of relative inactivity, specified by the Inactive Period, occurs. If an interval longer than Inactive Time-Out passes before the persistent image can begin, the persistent image cannot be taken and an error is displayed in the NAS Manager status indicator and logged in the event log.
  
  
• Image Directory Name — Specifies the directory name which is to be used for the persistent image mount point. Each persistent image appears as a subdirectory in the volume which is being imaged. The entire content of the volume, as it existed when the persistent image was created, appears under this directory.
  
  

3. If you need to re-establish the system defaults, click Restore Defaults.
   
   
4. Click OK to update the global settings.
   
   

Configuring Persistent Image Volume Settings

You can modify volume settings by performing the following steps:

1. On the NAS Manager primary menu, click Disks, and then click ActiveArchive.
   
   
2. Click Volume Settings.
   
   
3. Click the radio button adjacent to the volume setting you want to change.
   
   
4. Click Configure... .
   
   
5. Use the appropriate menus to configure the following options.
   
   

NOTE: Before changing the cache size, you must delete all persistent images on that volume.

• Cache Full Warning Threshold — Defines the percentage of cache space used that triggers warning messages to the system event log.
  
  
• Begin Deleting Images — Defines the percentage of cache space used that triggers automatic deletion of the oldest persistent images with the lowest retention weight on the system. Automatic persistent image deletions are recorded in the system log.
  
  
• Cache Size — Specifies the percentage of the volume that is allocated to the cache file. Increasing this value allows more and larger persistent images to be maintained. Ensure that adequate space is available on the persistent image files' location drive.
  
  

6. If you need to re-establish the system defaults, click Restore Defaults.
   
   
7. Click OK.
   
   

Accessing Stored Persistent Images in Dell ActiveArchive

NOTE: Only Windows clients (CIFS) can access Dell ActiveArchive persistent images.

NOTE: The name of the utility that creates persistent images is Dell ActiveArchive. The name of the directory where Dell ActiveArchive persistent images are stored is ActiveArchive.

NOTE: The ActiveArchive directory is a hidden folder. You must configure your system to view hidden files and folders to view your ActiveArchive directory.

1. On the NAS Manager primary menu, click the Maintenance tab.
   
   
2. Click Terminal Services.
   
   
3. Log on to a Terminal Services Advanced Client session.
   
   
4. If the PowerVault Advanced Administration Menu window is displayed, click Exit, and then click OK to close it.
   
   
5. Right-click My Appliance.
   
   
6. Click Map Network Drive from the menu.
   
   
7. Map to the root of the ActiveArchives volume.
   
   

Use "$" to specify the root of the volume. For example, in the Folder field, type \\<Dellxxxxxxx>\e$, where <Dellxxxxxxx> is the name of the PowerVault 715N system and where e is the drive letter of the volume.

8. Use Microsoft Windows Explorer to navigate to the ActiveArchive directory on the newly mapped drive.
   
   

Restoring Volumes From an Existing Persistent Image

To restore a volume(s) from a persistent image, you must select the persistent image to be restored. Ensure that you select the persistent image carefully because any activity that has occurred after the persistent image was taken is lost.

NOTICE: Restoring a volume restores the volume back to the state of the volume at the time the persistent image was made. This restore is a destructive process.

NOTICE: A volume is dismounted during a restore. All reads and writes to a volume that occur during the restore process are denied. Therefore, you must stop all I/O traffic to a volume while restoring it.

To restore volumes from a persistent image, perform the following steps:

1. On the NAS Manager primary menu, click Disks, then click ActiveArchive.
   
   
2. Click Restore Persistent Images.
   
   
3. On the Persistent Images to Restore page, click the radio button next to the persistent image that is to be restored.
   
   
4. In the Tasks list, click Restore.
   
   
5. Click OK to restore the volumes protected by the persistent image, or click Cancel to leave the volume intact.
   
   

NOTE: Restoring persistent images that contain multiple volumes restores all of the volumes in the persistent image.

NOTE: If you want the ability to restore a single volume, you must take single volume persistent images.

Changing the Dell ActiveArchive Event Log Language

Applying a selected language changes the graphical user interface to that language, but it does not change the language in which the Dell ActiveArchive event log messages are generated. The messages are generated in English unless you run a batch file to change the language to one of the following supported languages:

• English
  
  
• French
  
  
• German
  
  
• Japanese
  
  
• Spanish
  
  

To change the language in which the Event Log messages are generated, perform the following steps:

1. On the NAS Manager primary menu, click the Maintenance tab.
   
   
2. Click Terminal Services to create a Terminal Services Advanced Client session with the NAS appliance.
   
   
3. Log on to the system as an administrator.
   
   
4. If the Advanced Administration Menu is open, click Exit, and then OK to close it.
   
   
5. Open the Microsoft Windows Explorer, expand the C:\ hard drive directory and the Dell directory.
   
   
6. Open the AArchive_Langpatch directory.
   
   
7. Double-click the appropriate batch file, such as the english.bat file for English or the japanese.bat file for Japanese.
   
   
8. After the batch file has run, reboot your system.
   
   

Back to Contents Page