You can connect multiple on-premises Cloud Storage Gateway (CSG) agents to an Object Storage Service (OSS) bucket by using a file gateway. If data changes occur in the OSS bucket, you can use the express synchronization feature of CSG to synchronize these changes to the connected agents.
Prerequisites
- A file gateway is created and a cache disk is attached to it. For more information, see Create a file gateway and Attach a cache disk.
- An OSS bucket is created. For more information, see Create buckets.
- A Network File System (NFS) or Server Message Block (SMB) share is created and configured for the file gateway. For more information, see Manage shares.
- Message Service (MNS) is activated and authorized. For more information, see Activate MNS and authorize RAM users to access MNS.
Background information
When you configure the express synchronization feature, you can add one or more shares that are connected to the same OSS bucket to an express synchronization group. All data changes in the bucket are simultaneously synchronized to the CSG agents that are mapped to the shares in the express synchronization group. You do not need to separately synchronize data changes from the bucket. This improves the efficiency and accuracy of data synchronization.
Express synchronization must be used together with MNS. If you enable express synchronization, you are charged for using MNS. For information about MNS billing, see Pricing.
Create a synchronization group
To enable express synchronization, you must create a synchronization group and add shares to the group. Data is synchronized by using these shares.
- Log on to the CSG console.
- In the upper-left corner of the console, select the region where the file gateway is deployed.
- In the left-side navigation pane, click Express Sync.
- In the upper-right corner of the Sync Groups page, click Create.
- In the Create Sync Group wizard, set the following parameters in the Basic Information step, and click Next.
Parameter Description Sync Group Name Enter the name of the synchronization group. Note The synchronization group name must be 1 to 128 characters in length, and can contain letters, digits, periods (.), underscores (_), and hyphens (-). It must start with a letter.OSS Region The region where the OSS bucket resides. Bucket Name Select the name of the OSS bucket. You can select only one OSS bucket for an express synchronization group. All data changes in the bucket are synchronized to the CSG agents that are mapped to the shares in the group. Note If no share is connected to the OSS bucket, no OSS bucket is available in the drop-down list. In this case, you must create a share in the file gateway to map your CSG agent to the OSS bucket. For more information, see Manage shares.Bucket Subdirectory Select a subdirectory if you need to synchronize data from a specific subdirectory of the bucket. - In the Sync Group Settings step, select the shares that you want to add to the synchronization group from the Available Shares section and click the > icon. After these shares are displayed in the Selected Shares section, click Next.
To remove a share from the synchronization group, select the share in the Selected Shares section and click the < icon.
Note After you add an NFS share to a synchronization group, you can specify the noac parameter when you mount the share to a local directory on the CSG agent. This allows you to view the synchronization result at the earliest opportunity. For more information, see Access an NFS share directory. - In the Confirmation step of the Create Sync Group wizard, confirm the information of the synchronization group, and click OK.
Manage a synchronization group
After you create a synchronization group, all data changes in the OSS bucket are automatically synchronized to the CSG agents that are mapped to the shares in the synchronization group. You can perform the following operations to manage a synchronization group:
- View the details of a synchronization group
On the Sync Groups page, click the synchronization group name in the Sync Group Name column or click Details in the Actions column.
In the Sync Group Details dialog box, you can view the details of the synchronization group. You can also click the
icon to view the details in a list, or click the 
icon to view the details on a map. The Sync Group Details dialog box shows the basic information of the synchronization group and the shares in the group. You can also view the following information from the list. Item Description Message Topic Name The name of the MNS topic that is used by the synchronization group. Shared Status The status of a share in the synchronization group. The share can be in one of the following states: - Full Data Sync Awaiting: indicates that the share is waiting for the initial full synchronization.
- Full Data Sync in Progress: indicates that the share is being used for the full synchronization.
- Sync Normal: indicates that the share is being used to synchronize data as expected.
- Express Sync Disabled: indicates that the express synchronization feature is disabled for the share.
- Message Queue Inaccessible: indicates that the queue that corresponds to the share cannot be accessed.
- Message Topic Inaccessible: indicates that the topic that corresponds to the share cannot be accessed.
- Message Queue and Topic Inaccessible: indicates that the queue and topic that correspond to the share cannot be accessed.
Message Queue Name The name of the MNS queue that is used by the synchronization group. - Add a share to or remove a share from a synchronization group
Find the synchronization group and click Settings in the Actions column. In the Set Sync Group dialog box, add a share to or remove a share from the synchronization group. To add or remove a share, follow the instructions in Step 6 in the Create a synchronization group section.
- Delete a synchronization group
Find the group on the Sync Groups page and click Delete in the Actions column. In the message that appears, click OK.