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Protecting an entire server

Use these instructions to protect an entire server.

1. Click Get Started from the toolbar.
2. Select Double-Take Availability and click Next.
3. Select Protect files and folders or an entire server and click Next.

4. Choose your source server. This is the server that you want to protect.

   

   • Current Servers—This list contains the servers currently available in your console session. Select your source server from the list.
   • Find a New Server—If the server you need is not in the Current Servers list, click the Find a New Server heading. From here, you can specify a server along with credentials for logging in to the server. If necessary, you can click Browse to select a server from a network drill-down list.
5. Click Next to continue.
6. On the Choose Data page, under Server Workloads, select Full-Server Failover.

7. If you want to specifically include or exclude data to be protected, click the Replication Rules heading and expand the volumes under Folders. Items with a green highlight are included in the protection. Items highlighted in yellow have a subset of the items included in the protection. If there is no highlight, the item is not included for protection. To modify the items selected for protection, highlight a volume, folder, or file and click Add Rule. You can also enter a rule, including a wildcard specification, manually. Specify if you want to Include or Exclude the item from protection. Also, specify if you want the rule to be recursive, which indicates the rule should automatically be applied to the subdirectories of the specified path. If you do not select Recurse, the rule will not be applied to subdirectories.

   If you need to remove a rule, highlight it in the list at the bottom and click Remove Rule. Be careful when removing rules. Double-Take Availability may create multiple rules when you are adding directories. For example, if you add C:\Data to be included in protection, then C:\ will be excluded. If you remove the C:\ exclusion rule, then C:\Data rule will be removed also. Items in italics text cannot be removed because they are part of the system state.

   

8. Click Next to continue.

9. Choose your target server. This is the server that will store the replica data from the source.

   

   • Current Servers—This list contains the servers currently available in your console session. Select your target server from the list.
   • Find a New Server—If the server you need is not in the Current Servers list, click the Find a New Server heading. From here, you can specify a server along with credentials for logging in to the server. If necessary, you can click Browse to select a server from a network drill-down list.
10. Click Next to continue.

11. You have many options available for your full-server job. Click a link below to see the options available for that section of the Set Options page.

    Job Name 

    If desired, specify a unique name for your job.

    Failover Monitor

    

    • Monitor these addresses—Select each Source IP Address that you want the target to monitor. A selected IP address has a checkmark in the box next to it. In the event all of the monitored IP addresses fail, failover will be triggered.
    • Consider the source server failed after this duration—The target sends monitor requests to the source to determine if it is online. Specify the length of time, in hours:minutes:seconds, to wait before triggering failover when the target has not received responses from the source to its monitor requests. Consider a shorter amount of time for servers, such as a web server or order processing database, which must remain available and responsive at all times. Shorter times should be used where redundant interfaces and high-speed, reliable network links are available to prevent the false detection of failure. If the hardware does not support reliable communications, shorter times can lead to premature failover. Consider a longer amount of time for machines on slower networks or on a server that is not transaction critical. For example, failover would not be necessary in the case of a server restart.
    • Monitoring method—This option determines how the target monitors the source for a failure.
    • Network service—Source availability will be tested by an ICMP ping to confirm the route is active.
    • Replication service—Source availability will be tested by pinging the Double-Take service.
    • Network and replication services—Source availability will be tested by both an ICMP ping to confirm the route is active and by pinging the Double-Take service.
    • No monitoring—Double-Take Availability will not actively monitor the source. You will be responsible for identifying when a failure has occurred and initiating failover manually.
    Failover Options

    

    • Wait for user to initiate failover—By default, the failover process will wait for you to initiate it, allowing you to control when failover occurs. When a failure occurs, the job will wait for you to manually initiate the failover process. Disable this option only if you want failover to occur immediately when a failure occurs. This option is not configurable if the Monitoring method is set to No Monitoring.

    • Scripts—You can customize failover by running scripts on the target. Scripts may contain any valid Windows command, executable, or batch file. The scripts are processed using the same account running the Double-Take service, unless you have identified a specific account through the server's properties. Examples of functions specified in scripts include stopping services on the target before failover because they may not be necessary while the target is standing in for the source, stopping services on the target that need to be restarted with the source’s machine name and/or IP address, starting services or loading applications that are in an idle, standby mode waiting for failover to occur, notifying the administrator before and after failover occurs, and so on. There are two types of failover scripts.

      • Pre-failover script—This script runs on the target at the beginning of the failover process. Specify the full path and name of the script file.
      • Post-failover script—This script runs on the target at the end of the failover process. Specify the full path and name of the script file.
      • Arguments—Specify a comma-separated list of valid arguments required to execute the script.
      • Delay until script completes—Enable this option if you want to delay the failover process until the associated script has completed. If you select this option, make sure your script handles errors, otherwise the failover process may never complete if the process is waiting on a script that cannot complete.

      Scripts will run but will not be displayed on the screen if the Double-Take service is not set to interact with the desktop. Enable this option through the Windows Services applet.

    Reverse Protection

    

    • Enable reverse protection—After failover, your target server is lost. Reverse protection allows you to store a copy of the target's system state on the source server, so that the target server will not be lost. The reverse process will bring the target identity back on the source hardware and establish protection. After the reverse, the source (running on the original target hardware) will be protected to the target (running on the original source hardware).

      In order to reverse your protection, you must have at least two IP addresses on each server. One (or more) will be monitored and failed over and should be the production IP address(es) that your users access. One IP address, called a reserved IP address, will be used for the reverse process and will not failover or reverse, remaining with the server hardware. Ideally, this reserved IP address should not be used for production communications. The reserved IP address can be on the same or a different subnet from your production IP addresses, however if the subnet is different, it should be on a different network adapter.

      The reserved IP addresses will also be used to route Double-Take Availability data.

      • Select a reserved IP address on the source—Specify a reserved IP address on the source which will be used to permanently identify the source server. The IP address you specify will not be failed over to the target in the event of a failure. This allows you to reverse protection back to the source after a failover.
      • Select a reserved IP address on the target—Specify a reserved IP address on the target which will be used to permanently identify the target server. The IP address you specify will not be lost during failover. This allows you to reverse protection back to the source after a failover.

      When reverse protection is enabled, an image of the target's system state is mirrored to the source server. This mirror may cause a performance impact on your source server. This impact is only temporary, and system performance will return to normal when the reverse protection mirror is complete. To maintain system performance on the source, the target's system state is not continuously replicated to the source. You can manually update the image of the target's system state by viewing the job details and clicking Update under Target Server Image.

       

    • Disable reverse protection—If you do not use reverse protection, after a failover, your target server will be lost. In order to continue protecting your data, you will have to manually rebuild your original source hardware and restart protection, which can be a long and complicated process.
    • Send data to the target server using this route—Specify an IP address on the target to route Double-Take Availability data. This allows you to select a different route for Double-Take Availability traffic. For example, you can separate regular network traffic and Double-Take Availability traffic on a machine with multiple IP addresses.
    Staging Folder Options 

    

    • Select additional folders from the source that need to be staged—Applications running on the target that cannot be stopped will cause retry operations because Double-Take Availability will be unable to write to open application files. In this case, you will want to mirror those application files to a staging location instead of their actual location. Generally, this will only apply to applications that are not installed in the Windows Program Files directory. In this case, click Add and specify the folder that you want staged. Any staged folders will be applied to their actual installation location during failover.
    • Show system state and profile folders—This option displays the list of essential system state and profile folders that will be staged automatically. These essential items are displayed in a lighter color than folders you have manually added, and they cannot be removed from the list.
    Network Configuration

    

    • Apply source network configuration to the target—If you select this option, the source IP addresses will be failed over to the target.
    • Retain target network configuration—If you select this option, the source IP addresses will not be failed over to the target. The target will retain all of its original IP addresses. If your target is on a different subnet (typical of a WAN environment), you should select this option.

    • Update DNS server—Specify if you want Double-Take Availability to update your DNS server on failover and reverse. If DNS updates are made, the DNS records will be locked during failover and then unlocked during reverse.

      DNS updates only work for Active Directory integrated DNS servers that have the DNS WMI Provider installed. This is a separate installation for Windows 2000 but is automatic for Windows 2003 and later.

       

      Expand the DNS Options section to configure how the updates will be made. The source's domain will be discovered and displayed.

    • Update this DNS server during failover—Select the name or IP address of the DNS server that you want to update during failover and reverse.
    • User name—Specify a user that has privileges to access and modify DNS records. The account must be a DNS Admin for the domain. You can enter a user name for a different domain by entering a fully qualified user name. The fully qualified user name must be in the format domain\username or username@domain. If you enter a non-qualified name, the highlighted domain will be used.
    • Password—Specify the password that is associated with the user name you entered.
    • Update these source DNS entries with the corresponding target IP address—For each non-reserved IP address on the source, specify what address you want DNS to use after failover.
    • Update TTL—Specify the length of time, in seconds, for the time to live value for all modified DNS A records. Ideally, you should specify 300 seconds (5 minutes) or less.
    Network Adapter Options

    

    • Map source network adapters to target network adapters—Specify how you want the IP addresses associated with each NIC on the source to be mapped to a NIC on the target. Do not mix public and private networks. Also, if you have enabled reverse protection, make sure that your NICs with your reserved IP addresses are mapped to each other.
    Snapshots & Compression

    

    A snapshot is an image of the source replica data on the target taken at a single point in time. Snapshots allow you to view files and folders as they existed at points of time in the past, so you can, for example, recover from cases where corrupted source data was replicated to the target. When failover is triggered, you can use the live target data at the time of failover or you can failover to a snapshot of the target data.

    • Enable scheduled snapshots—Enable snapshots if you want to be able to use them at failover time. If snapshots are disabled, the live data on the target at failover time will be used.
    • Take snapshots on this interval—Specify the interval (in days, hours, or minutes) for taking snapshots.
    • Begin immediately—Select this option if you want to start taking snapshots immediately after the protection is established.
    • Begin at this time—Select this option if you want to start taking snapshots starting at a later date and time. Specify the date and time parameters to indicate when you want to start.

    • Enable compression—To help reduce the amount of bandwidth needed to transmit Double-Take Availability data, compression allows you to compress data prior to transmitting it across the network. In a WAN environment this provides optimal use of your network resources. If compression is enabled, the data is compressed before it is transmitted from the source. When the target receives the compressed data, it decompresses it and then writes it to disk. On a default Double-Take Availability installation, compression is disabled. To enable it, select this option and set the level from Minimum to Maximum to suit your needs.

      Keep in mind that the process of compressing data impacts processor usage on the source. If you notice an impact on performance while compression is enabled in your environment, either adjust to a lower level of compression, or leave compression disabled. Use the following guidelines to determine whether you should enable compression:

      • If data is being queued on the source at any time, consider enabling compression.
      • If the server CPU utilization is averaging over 85%, be cautious about enabling compression.
      • The higher the level of compression, the higher the CPU utilization will be.
      • Do not enable compression if most of the data is inherently compressed. Many image (.jpg, .gif) and media (.wmv, .mp3, .mpg) files, for example, are already compressed. Some images files, such as .bmp and .tif, are uncompressed, so enabling compression would be beneficial for those types.
      • Compression may improve performance even in high-bandwidth environments.
      • Do not enable compression in conjunction with a WAN Accelerator. Use one or the other to compress Double-Take Availability data.

      All jobs from a single source connected to the same IP address on a target will share the same compression configuration.

       

    Scripts

    

    You can customize mirroring by running scripts on the target at pre-defined points in the mirroring process. Scripts may contain any valid Windows command, executable, or batch file. The scripts are processed using the same account running the Double-Take service, unless you have identified a specific account through the server's properties. There are three types of mirroring scripts.

    • Mirror Start—This script starts when the target receives the first mirror operation. In the case of a difference mirror, this may be a long time after the mirror is started because the script does not start until the first different data is received on the target. If the data is synchronized and a difference mirror finds nothing to mirror, the script will not be executed. Specify the full path and name of the Script file.
    • Mirror Complete—This script starts when a mirror is completed. Because the mirror statistics may indicate a mirror is at 99-100% when it is actually still processing (for example, if files were added after the job size was calculated, if there are alternate data streams, and so on), the script will not start until all of the mirror data has been completely processed on the target. Specify the full path and name of the Script file.
    • Mirror Stop—This script starts when a mirror is stopped, which may be caused by an auto-disconnect occurring while a mirror is running, the service is shutdown while a mirror is running, or if you stop a mirror manually. Specify the full path and name of the Script file.
    • Arguments—Specify a comma-separated list of valid arguments required to execute the script.
    • Allow script to interact with desktop—Enable this option if you want the script processing to be displayed on the screen. Otherwise, the script will execute silently in the background.
    • Delay until script completes—Enable this option if you want to delay the mirroring process until the associated script has completed. If you select this option, make sure your script handles errors, otherwise the mirroring process may never complete if the process is waiting on a script that cannot complete.
    • Test—You can test your script manually by clicking Test. Your script will be executed if you test it. If necessary, manually undo any changes that you do not want on your target after testing the script.

    Mirror scripts are dependent on the target and the Target Path Mappings specified under the Network Route & Folder Selection section. If you establish mirroring scripts for one job and then establish additional jobs to the same target using the same target path mapping, the mirroring scripts will automatically be applied to those subsequent jobs. If you select a different target path mapping, the mirroring scripts will have to be reconfigured for the new job(s).

     

    Mirror, Verify & Orphaned Files

    

    • Mirror all files—All protected files will be mirrored from the source to the target.
    • Mirror different files—Only those protected files that are different based on date and time, size, or attributes will be mirrored from the source to the target.

    • Mirror only if the file on the source is newer than the copy on the target—Only those protected files that are newer on the source are mirrored to the target.

      If you are using a database application, do not use this option unless you know for certain that you need it. With database applications, it is critical that all files, not just some of the files that might be newer, get mirrored.

       

    • Use block checksum for comparisons—For those files flagged as different, the mirroring process can perform a block checksum comparison and send only those blocks that are different.
    • Behavior when automatically reconnecting—Specify which mirroring option to use when Double-Take Availability automatically reconnects an existing protection.

    • Calculate size of protected data upon connection—Specify if you want Double-Take Availability to determine the mirroring percentage calculation based on the amount of data being protected. If the calculation is enabled, it is completed before the job starts mirroring, which can take a significant amount of time depending on the number of files and system performance. If your job contains a large number of files, for example, ten thousand or more, you may want to disable the calculation so that data will start being mirrored sooner. Disabling calculation will result in the mirror status not showing the percentage complete or the number of bytes remaining to be mirrored.

      The calculated amount of protected data may be slightly off if your data set contains compressed or sparse files.

       

    • Enable scheduled verification—Verification is the process of confirming that the source replica data on the target is identical to the original data on the source. Verification creates a log file detailing what was verified as well as which files are not synchronized. If the data is not the same, can automatically initiate a remirror, if configured. The remirror ensures data integrity between the source and target. When this option is enabled, Double-Take Availability will verify the source replica data on the target and generate a verification log.

      Because of the way the Windows Cache Manager handles memory, machines that are doing minimal or light processing may have file operations that remain in the cache until additional operations flush them out. This may make Double-Take Availability files on the target appear as if they are not synchronized. When the Windows Cache Manager releases the operations in the cache on the source, the files will be updated on the target.

       

    • Verify on this interval—Specify the interval between verification processes.
    • Begin immediately—Select this option if you want to start the verification schedule immediately after the job is established.
    • Begin at this time—Select this option if you want to start taking snapshots at the specified date and time.
    • Mirror files to the target server when verifying—When this option is enabled, in addition to verifying the data and generating a log, Double-Take Availability will also mirror to the target any protected files that are different on the source.

    • Mirror only if the file on the source is newer than the copy on the target—If you are mirroring files to the target during the verification process, select this option if you only want to mirror protected files that are newer on the source than on the target.

      If you are using a database application, do not use this option unless you know for certain that you need it. With database applications, it is critical that all files, not just some of the file that might be newer, get mirrored.

       

    • Use block checksum for comparisons—Select this option to have the verification process perform a block checksum comparison to determine which block are different.
    • Log orphaned files—An orphan file is a file that exists in the source replica data on the target, but does not exist in the protected data on the source. For example, an orphan file may be created if you delete a protected file from the source while the job is stopped. Because the job is stopped, the delete operation is not replicated to the target, so the file is not deleted on the target. This option specifies if orphaned files are logged to the Double-Take Availability log file on the target during a mirror or verification.

    • Move or delete orphaned files—Enable this option to move or delete orphaned files on the target during a mirror or verification.

      • Move or delete all orphaned files—Select this option if you want move or delete all orphaned files.
      • Move or delete orphaned files not modified in the last—Select this option if you want to move or delete only those orphaned files older than the specified time.
      • Delete orphaned files—Select this option if you want to delete orphaned files.
      • Move orphaned files to this folder—Select this option if you want to move orphaned files. Identify the location on the target where you want to move the orphaned files. Make sure the location you specify is not included in the location where the source replica data is located so that the orphaned files are only moved once.

      Orphan file configuration is a per target configuration. All jobs to the same target will have the same orphan file configuration.

      The orphans feature does not move or delete alternate data streams. To do this, use a full mirror, which will delete the additional stream(s) when the file is re-created.

      If Double-Take Availability is configured to move orphan files, the Double-Take Availability log file will indicate that orphan files have been deleted even though they have actually been moved. This is a reporting issue only.

      If delete or move orphaned files is enabled, carefully review any replication rules that use wildcard definitions. If you have specified wildcards to be excluded from protection, files matching those wildcards will also be excluded from orphan file processing and will not be deleted from the target. However, if you have specified wildcards to be included in your protection, those files that fall outside the wildcard inclusion rule will be considered orphaned files and will be deleted from the target.

       

    Target Services Options

    

    • Services to leave running on the target server during protection—Double-Take Availability controls which services are running and stopped on the target during protection. You can specify which services you want to keep running by clicking Add and selecting a service from the list. If you want to remove a service from the list, highlight it and click Remove.

      Services are stopped on the target to protect against retry operations. Do not leave services running unless absolutely necessary.

       

    • Show essential services—This option displays the list of essential services that will remain running on the target. The essential services are displayed in a lighter color than services you have manually added. The essential services cannot be removed from the list.
    Bandwidth

    

    Bandwidth limitations are available to restrict the amount of network bandwidth used for Double-Take Availability data transmissions. When a bandwidth limit is specified, Double-Take Availability never exceeds that allotted amount. The bandwidth not in use by Double-Take Availability is available for all other network traffic.

    • Do not limit bandwidth—Double-Take Availability will transmit data using 100% bandwidth availability.
    • Use a fixed limit—Enter a value, in bytes per second, to limit data transmission. This is the maximum amount of data that will be transmitted per second.
    • Use scheduled limits—Use a schedule to limit bandwidth for different times. Schedules that you create will be maintained if you change to a fixed limit or to no limit.
    • New—Click New to create a new scheduled bandwidth limit. Specify the following information.
    • Daytime entry—Select this option if the start and end times of the bandwidth window occur in the same day (between 12:01 AM and midnight). The start time must occur before the end time.
    • Overnight entry—Select this option if the bandwidth window begins on one day and continues past midnight into the next day. The start time must be later than the end time, for example 6 PM to 6 AM.
    • Day—Enter the day on which the bandwidth limiting should occur. You can pick a specific day of the week, Weekdays to have the limiting occur Monday through Friday, Weekends to have the limiting occur Saturday and Sunday, or Every day to have the limiting repeat on all days of the week.
    • Start time—Enter the time to begin bandwidth limiting.
    • End time—Enter the time to end bandwidth limiting.
    • Preset bandwidth—Select a bandwidth limit rate from the common bandwidth limit values. The Bandwidth field will automatically update to the bytes per second value for your select bandwidth.
    • Bandwidth—If desired, modify the bandwidth using a bytes per second value. The minimum limit should be 28000 bytes per second.
    • Edit—Click Edit to modify an existing scheduled bandwidth limit.
    • Delete—Click Delete to remove a scheduled bandwidth limit.

    All jobs from a single source connected to the same IP address on a target will share the same bandwidth configuration.

     

12. After you have configured your options, click Next to continue.

13. Double-Take Availability validates that your source and target are compatible for your job type. The Summary page displays the options you selected in your workflow and any additional validation items.

    Errors are designated by a white X inside a red circle. Warnings are designated by a black exclamation point (!) inside a yellow triangle. A successful validation is designated by a white checkmark inside a green circle. Click on any of the validation items to see details. You must correct any errors before you can enable protection. Depending on the error, you may be able to click Fix or Fix All and let Double-Take Availability correct the problem for you. For those errors that Double-Take Availability cannot correct automatically, you will need to modify the source or target to correct the error, or you can select a different target. You must revalidate the selected servers, by clicking Recheck, until the validation check passes without errors.

14. Once your servers have passed validation and you are ready to establish protection, click Finish, and you will automatically be taken to the Manage Jobs page.

Do not create any other full-server jobs from your source or to your target. You can create files and folders jobs, but full-server jobs must be used in a one-to-one configuration only.