Using Tiger Bridge you can automatically migrate all your cloud data to a new cloud storage provider ensuring that all data is migrated and access to it is not interrupted during the migration process.
This article outlines the two possible cloud-to-cloud data migration scenarios using Tiger Bridge. Both require a designated on-premises storage as an intermediate tier for migrating data from one cloud storage provider to another. Choosing one or the other scenario depends on whether the on-prem storage has enough capacity to simultaneously host all your cloud data, in which case you can migrate it in one go. In case data that needs to be migrated cannot all fit the local storage, you can let Tiger Bridge automatically migrate it in batches.
Table of Contents:
Scenario 1: Migrating Data in One Go
Scenario 2: Migrating Data in Batches
Step-by-step Procedures
Pair the Local Source Storage with Your Current Cloud Storage Provider
Pair the Local Source Storage with Your New Cloud Storage Provider
Pair a NAS Source with the New Cloud Storage
Ensure All Data Is Retrieved on the Source
Ensure All Data Is Replicated on the New Cloud Storage
Troubleshooting Failed Replication
Configure Reclaim Space Policy to Free Space on the Source
Optimizing the Data Migration Process
Increase the Number of Parallel Threads during Data Replication to Speed It Up
Automatic Rehydration of Offline Files
Migrate a Specific Version of a File
Scenario 1: Migrating Data in One Go
As long as the data you want to migrate to another cloud storage provider can all fit the designated local storage, which should be used as an intermediate tier, the migration procedure goes like this:
- If you have not done so yet, in Tiger Bridge, pair the local source storage with your current cloud target provider.
- Ensure all data is retrieved locally from your current cloud storage, then disband the pair (select the source in the left pane and click Delete Source).
Note: If some data is located in the archive of the cloud storage, requesting to retrieve it may rehydrate it to an intermediate tier of the target instead. Consider enabling automatic rehydration of offline files in Tiger Bridge to avoid having to repeat the Retrieve command.
Important: If versioning is enabled on your cloud storage, only the latest version of a file can be retrieved locally. If you are using Tiger Bridge versioning, you can select which version of a file to migrate, by following these steps. - Pair the local source storage with your new cloud storage.
- Replicate all data to the new cloud storage (see Ensure All Data Is Replicated on the New Cloud Storage).
- Once all data is replicated, disband the new pair if needed and start accessing your data from the new cloud storage location.
Scenario 2: Migrating Data in Batches
Organizations usually resort to offloading data onto the cloud to save on local storage costs. Thus, retrieving all your cloud data to your on-prem storage is usually impossible in one go as it simply cannot be accommodated there. With the help of Tiger Bridge, you can deploy a setup in which the on-prem storage hosts only the files that are being migrated as well as the files that are currently being accessed by users. If a file is available only on the old target, Tiger Bridge automatically retrieves it on the source, replicates it to the new target, and moves on to the next file queued for replication. If there is not enough free space on the source to accommodate an already replicated file when the next file in the queue has to be retrieved from the old target, Tiger Bridge replaces the already replicated file with a stub, this way freeing space on the source. Should a request for access to a file that is not present on the source, come from a user or an application, Tiger Bridge automatically retrieves that file, pausing the queue of files scheduled for replication on the new target.
This setup keeps all data on both cloud storage targets until the migration is completed. It is also fully transparent to users and applications – a request for access to a specific file on the source may be delayed only for the time needed to retrieve the file locally if it is not present at the moment.
This migration scenario goes through the following steps:
- If you have not done so yet, in Tiger Bridge, pair your current cloud storage with a local source and synchronize their data.
- Export the local source as an SMB or NFS share.
- Pair the exported SMB/NFS share with the new cloud storage target.
- Configure a Replication policy that automatically replicates all data from the current cloud storage target to the new one (see Ensure All Data Is Replicated on the New Cloud Storage).
- Configure Reclaim Space policy that replaces files already replicated to the new cloud storage target with stubs in order to free space for new files to be replicated.
- Verify that all data is migrated to the new cloud storage target and optionally disband the local source and the old cloud storage target (in the left pane, select the source and click Delete Source).
Step-by-step Procedures
Pair the Local Source Storage with Your Current Cloud Storage Provider
- In the Tiger Bridge Configuration, click Tiger Bridge in the left pane and then click Add source.
- Browse to and select the local NTFS/ ReFS volume you will use as an intermediate tier for migrating data, then click Select Folder.
- In the Tiger Bridge Target dialog, click Public Cloud, then select your current cloud storage target provider and click OK.
- In the right pane of the Configuration, fill in the required authentication details to let Tiger Bridge gain access to the target and select the bucket/container from which data will be migrated, then click Apply.
- In the “Existing cloud data action” dialog, do one of the following:
- If you are migrating data in one go, select “Restore all data” and click OK.
- If you are migrating data by retrieving and replicating one file at a time, select “Import all metadata” and click OK.
Note: If you have already paired a source with a cloud storage target to ensure their contents are synchronized, in Windows Explorer, right-click the source, and in the context menu, click “Tiger Bridge |
Synchronize Recursively”.
- In the Configuration, click Resume to resume automatic Tiger Bridge operations.
Pair the Local Source Storage with Your New Cloud Storage Provider
- In the Tiger Bridge Configuration, click Tiger Bridge in the left pane and then click Add source.
- Browse to and select the local NTFS/ ReFS volume to which you have retrieved all data that you want to migrate to the new storage provider, then click Select Folder.
Note: If the source is still paired with the cloud storage from which you want to migrate data, select it in the left pane and click Delete Source, then repeat the step above. - In the Tiger Bridge Target dialog, click Public Cloud, then select the cloud storage provider to which you want to migrate data and click OK.
- In the right pane of the Configuration, fill in the required authentication details to let Tiger Bridge gain access to the target and select the bucket/container to which data will be migrated, then click Apply.
- In the “Existing cloud data action” dialog, do one of the following:
- If you are migrating data in one go, select “Restore all data” and click OK.
- If you are migrating data by retrieving and replicating one file at a time, select “Import all metadata” and click OK.
Note: If you have already paired a source with a cloud storage target to ensure their contents are synchronized, in Windows Explorer, right-click the source, and in the context menu, click “Tiger Bridge | Synchronize Recursively”.
- In the Configuration, click Resume to resume automatic Tiger Bridge operations.
Pair a NAS Source with the New Cloud Storage
To add as a NAS source the local storage on which you will retrieve data from your old cloud storage provider and replicate it to the new one, you must assign an empty folder on a locally mounted volume on the Tiger Bridge computer as the source’s control folder. This folder is used as a control location and contains a copy of each file on the NAS source in the form of a stub file. As a general rule, the capacity of the control folder must be at least 15% of the capacity of the data hosted on the source itself. While stub files take virtually no space, if you are migrating an enormous number of files the size of the control folder can affect the free space available locally. That is why it is advisable to use as a control folder a folder on another locally mounted volume and not the source location itself.
- In the Tiger Bridge Configuration, click Tiger Bridge in the left pane and then click Add source.
- Browse to and select the SMB/NFS share, which will host data that is to be migrated to the new storage provider, then click Select Folder.
- (SMB share only) In the NAS Credentials dialog, enter the username and password of a user with Full Control over the network share in the respective fields.
Important: You must enter the username in the following format [NAS server domain name or IP address]\[username]. For example, if the IP address of your NAS server is 10.200.0.65 and the name of the user, whose credentials you are providing is “test”, enter the following in the Username field:
10.200.0.65\test - In the Tiger Bridge Target dialog, click Public Cloud, then select the cloud storage provider to which you want to migrate data and click OK.
- In the right pane of the Configuration, fill in the required authentication details to let Tiger Bridge gain access to the target and select the bucket/container to which data will be migrated, then click Apply.
- In the “Existing cloud data action” dialog, select “No action” and click OK.
- In the Configuration, click Resume to resume automatic Tiger Bridge operations.
Ensure All Data Is Retrieved on the Source
Depending on the amount of data you are retrieving the process can take a significant amount of time. While Tiger Bridge is retrieving data from the target, its tray icon changes to this 
. Monitor the Tiger Bridge tray icon and once it changes to this 
, verify that all data is retrieved using these steps:
- In Windows Explorer, right-click the source and select Properties.
- In the Bridge tab, make sure the Reclaimed field contains 0 files:
If the Reclaimed field shows that there are still reclaimed files on your local storage, check the Tiger Bridge logs (right-click the tray icon and then select “Open Event Viewer”) for the following error: “Retrieving file <path to file on source> <process name> from the target failed.” If the message is present:
- Make sure the target is accessible.
- If the target is accessible, make sure the replicated file is not deleted from the target.
- If the file is deleted and your target has versioning turned on, attempt to undelete it on the target.
Important: Keep in mind that retrieving data from the archival tier/storage class usually takes longer. Also, on some targets, the request to retrieve data from the archival tier/storage class results in its rehydration to an intermediate tier/storage class and you need to repeat the retrieve data request by right-clicking the source in Windows Explorer and then selecting in the context menu “Tiger Bridge |
Retrieve Data“.
Ensure All Data Is Replicated on the New Cloud Storage
Tiger Bridge’s global Replication Policy takes care to automatically replicate all needed data from the source to your new cloud storage. If you use it with its default parameters, it will begin replicating all files that have not been accessed for 1 minute. To set in motion the replication process make sure automatic operations are not paused (the left pane of the Configuration displays “Tiger Bridge (running)”) and if needed click Resume at the bottom of the Configuration.
Depending on the amount of data the replication can take significant time. You can keep track of the process using the Tiger Bridge tray icon – while the replication queue is being processed the icon looks like this 
. Once all files are replicated to the target, it changes to this .
Troubleshooting Failed Replication
If the tray icon changes to this 
, Tiger Bridge has encountered a problem replicating one or more of the queued files. Note that the replication of a file is terminated if a user or application attempts to access it. You can also check the Tiger Bridge logs (right-click the tray icon and then select “Open Event Viewer”) for the following error: “Replication of file <path to file on source> failed.” If the message is present:
- Make sure the file is not corrupted.
- Make sure the target is still accessible and has not returned any errors.
In the Tiger Bridge Explorer, you can view a full list of all files whose replication has failed and attempt to replicate them again:
- Right-click the Tiger Bridge tray icon and click “Show failed files”.
- Click Settings and in the Settings dialog, clear the “Flat listing” check box to display all failed files, without having to browse your source’s folder structure.
- In the left pane of the Tiger Bridge Explorer, select the source and click “Retry selected” in the toolbar.
Configure Reclaim Space Policy to Free Space on the Source
When Tiger Bridge attempts to read a stub file that is not yet present on the new cloud storage in order to replicate it there, it triggers its retrieval on the source from your old cloud storage. If the source does not have enough free space to accommodate the file, the retrieval and consequent replication of the file will fail. To overcome this, you must add a Reclaim Space to your NAS source.
If you add the policy with its default settings, Tiger Bridge will immediately replace each file that it has already replicated to the new target with a stub, regardless of its size as long as it has not been accessed for more than 4 weeks. The time criteria parameter is ignored if the used space on the source reaches 90%. In this case, Tiger Bridge processes the queue of files scheduled for replacement with stubs, starting from the ones that are least recently accessed and proceeds with the reclaiming of space on the source until the used space falls below 90%. Decreasing the used space threshold will guarantee more free space for retrieving files that need to be replicated. At the same time, if users are working with files on the source, the lower the threshold the bigger the chance that an actively accessed file is replaced by a stub.
To add the Reclaim Space policy to the NAS source:
- In the Tiger Bridge Configuration, select the NAS source in the left pane and click Add policy.
- In the Policy Type dialog, select "Reclaim space" and click OK.
- In the right pane, select the Enabled check box, to enable the policy.
- To change the default parameters of the space reclaiming policy, do the following:
- In “Remove files not accessed for more than” specify for how long a file must not have been accessed for Tiger Bridge to replace it with a stub on the source.
- In “Bigger than”, specify how big a file should be for Tiger Bridge to replace it with a stub. To allow the replacement of all files regardless of their size, leave the default value of 0 Bytes.
- In “Start reclaiming space when used space exceeds” specify the used space threshold, which when exceeded triggers Tiger Bridge to reclaim space. To let Tiger Bridge reclaim space regardless of the used space, leave the value to 0%.
- In “Ignore access time criteria if the used space exceeds” specify the used space threshold, which when exceeded triggers the replacement of replicated files with stubs even if they do not yet meet the access time criteria.
- Click Apply and resume automatic Tiger Bridge operations.
Optimizing the Data Migration Process
Increase the Number of Parallel Threads during Data Replication to Speed It Up
By default, Tiger Bridge replicates files using four threads. You can increase the number of parallel threads in order to increase the replication speed, keeping in mind that using too many threads may hamper the performance of the Tiger Bridge computer.
To set the number of parallel threads during data replication:
- In the left pane of the Tiger Bridge Configuration, click Settings.
- In the right pane, click Advanced.
- In the “Threads count” field of the Advanced Settings dialog, specify the number of parallel threads used by Tiger Bridge during replication and then click OK.
- In the Settings pane, click Apply and when prompted, confirm that you want to restart the Tiger Bridge service.
Automatic Rehydration of Offline Files
By default, when you want to retrieve an offline file, you must first manually rehydrate it to the hot/cool tier of the target and only after that retrieve it on the source either manually or automatically. You can change this behavior and allow the automatic rehydration and consequent retrieval of the file when a user or application attempts to open the offline file on the source.
To enable automatic rehydration of offline files:
- Start the Registry Editor.
Tip: To start Registry Editor, on the Start menu, click Run, and in the dialog, type regedit. - Navigate to:
HKEY_LOCAL_MACHINE\SOFTWARE\Tiger Technology\tiger-bridge\tiersvc\settings - Right-click the active_restore_rehydrate string value and select Modify.
- To set Tiger Bridge to automatically rehydrate and then retrieve a file from the archival tier of the target when a user or an application attempts to open an offline file on the source, change the value to 1 and click OK.
- Run Command Prompt as an administrator.
Tip: To run Command Prompt as an administrator, click Start, type cmd, right-click Command Prompt, and select “Run as administrator”. - Restart the Tiger Bridge service, by executing the following:
net stop tiersvc
net start tiersvc
Migrate a Specific Version of a File
If versioning is enabled both in Tiger Bridge and on your current cloud storage, you can select which version of a file to migrate to your new cloud storage. By default, unless you have specified that the source file points to a specific version on the target, the last version of the file is used. You can select which version to retrieve from the target, by following these steps:
- In Windows Explorer, right-click the file and select Properties.
- In the Properties dialog, click the Versions tab.
- Tiger Bridge lists all available versions of the file in descending order, starting with the newest one. The icon of each version designates the tier on the target it is stored on, and the version currently stored on the source is displayed with a check mark.
- Select a file version in the list and click Restore.
- In Windows Explorer, right-click the folder or the whole source and select Properties.
- In the Properties dialog, select the Versions tab.
- Select the desired date and time in the Timestamp boxes and then click Analyze Content.
Note: Depending on the number of files in the folder and their size the analysis may take time. Keep track of the progress bar below, to make sure Tiger Bridge has gathered the complete information.
- Click “Timestamp Restoration…”.
Tiger Bridge displays a dialog, listing all files, whose current version on the source is different from the version replicated before the selected date and time. It also gives you information about the size of the current version on the source and the date the last version has been replicated as well as about the size and date of the version, which will be restored against the selected timestamp.
- In the left pane of the dialog, select a folder, to restore all its files to their version, replicated before the selected timestamp.
- Select whether to automatically retrieve on the source each file, whose current version differs from the one which will be restored.
- Select whether the version, which will be restored on the source should be added as the newest version on the target.
- Click Restore Selection.