Cloud Storage Gateway:Create a share

Create a share

1. On the Gateways page, click the ID of the file gateway. On the page that appears, click Shares > Create.

2. In the Bucket Settings step, configure the parameters described in the following table.

   Bucket Settings

   Parameter	Description
   Cross-border Binding	If you select Yes, you can access a bucket that resides in a different region from that of the gateway. If you select No, you can only access a bucket that resides in the same region as the gateway.
   OSS Endpoint	Select an endpoint for the region in which the bucket is located.
   Bucket Name	Specify the bucket. You can select an existing bucket from the drop-down list. You can also select the Subdirectory check box and enter a subdirectory of the bucket in the text box that appears. Note The name of a subdirectory can contain only letters and digits. Starting from V1.0.38, you can map the root directory of a file system to a subdirectory of the bucket. This way, you can isolate file access requests. You can specify an existing subdirectory or a subdirectory that does not exist in the bucket. After you create a share, the specified subdirectory serves as the root directory and stores all related files and directories. A file gateway does not support OSS buckets for which back-to-origin routing is configured. CSG cannot guarantee that only one write operation is performed on an object. Therefore, buckets for which retention policies are configured are not supported.
   Encrypt	Specify the encryption settings. You can select None, Server-side Encryption, or Gateway-side Encryption. If you select Server-side Encryption, you must specify a Key ID and an Encryption Algorithm. You can create a customer master key (CMK) in the Key Management Service (KMS) console. For more information, see Create a CMK. Encryption algorithms AES256 and SM4 are supported. If you enable the server-side encryption feature, you can bring your own key (BYOK). Keys that are imported from KMS are supported. After you enable the server-side encryption feature, the system encrypts files that are uploaded to OSS from the share by using the specified key. You can call the GetObject operation to check whether the specified object is encrypted. If the value of the x-oss-server-side-encryption field is KMS and the value of the x-oss-server-side-encryption-key-id field is the key ID in the response header, the object is encrypted. Important Only users on the whitelist can use this feature. The gateway-side encryption feature is available only for enhanced and performance-optimized gateways. For more information, see Enable gateway encryption. When you create a CMK in the KMS console, you must select the region in which the OSS bucket resides.
   Use SSL to Connect Bucket	If you select Yes, the bucket is connected over SSL.

3. In the Basic Information step, configure the parameters described in the following table.

   Basic Information

   Parameter	Description
   Share Name	Specify a name for the share. If you set the Protocol parameter to NFS, the share name is also used as the virtual path of the share when the mount operation is performed based on NFSv4. Note The name must be 1 to 32 characters in length, and can contain letters, digits, underscores (_), hyphens (-), and periods (.). It must start with a letter.
   Protocol	Specify the protocol that you use to connect to the OSS bucket. You can select NFS or SMB. Use the NFS protocol if you need to access the bucket from a Linux system. Use the SMB protocol if you need to access the bucket from a Windows system.
   Cache	Select an existing cache disk. Note Cache disk space is distributed based on the following rules: For a cache disk with a capacity of no more than 5 TB, 20% of that capacity is reserved for metadata storage. For example, if you attach a 40 GB cache disk, the actual space available for data storage is 32 GB. For a cache disk with a capacity of more than 5 TB, 1 TB is reserved for metadata storage. For example, if you attach a 20 TB cache disk, the actual space available for data storage is 19 TB.
   User Mapping	Specify the user mapping between the NFS client and the NFS server. none: The NFS client user is not mapped to the nobody user on the NFS server. root_squash: The NFS client that uses the root identity is mapped to the nobody user on the NFS server. all_squash: The NFS client is mapped to the nobody user on the NFS server regardless of the identity that the client uses. all_anonymous: The NFS client is mapped to the anonymous user on the NFS server regardless of the identity that the client uses. Note This parameter is available only when you set Protocol to NFS.
   Archive	Select whether to enable the archive feature. If you select Yes, the archive feature is enabled. You can use the archive feature to archive and restore files in a share. If you select No, the archive feature is disabled. Note This parameter is available only if you set Protocol to NFS and User Mapping to none. Basic file gateways do not support the archive feature. If you request to read an archived file from a gateway for which the archive feature is disabled, a request to restore the file is still initiated. If the file gateway uses an NFS share, no error is returned, but a certain level of I/O latency occurs. If the file gateway uses an SMB share, a short-lived error occurs, and the read operation is successful after the restoration process is complete.
   Browsable	Specify whether the share can be accessed by using Network Neighborhood. Note This parameter is available only if you set Protocol to SMB.
   Windows Permission Support	The access control settings. For more information about permission control, see Enable Windows permission support. Note This parameter is available only if you set Protocol to SMB. To enable Windows permission support, you must add the gateway to an AD domain first.
   Access-based Enumeration	After Windows ABE is enabled, users can only view files or directories that they have permissions to manage. Note This parameter is available only if you set Windows Permission Support to Yes.
   Add to Sync Group	Specify whether to add the share to a synchronization group. If you add the share to a synchronization group, the reverse synchronization feature is automatically disabled for the share. After you add the share to a synchronization group, all changes made to the data stored in the OSS bucket that corresponds to the share are synchronized to the on-premises client on which the share is mounted. Note To enable this feature, create a synchronization group first. Make sure that the synchronization group and the share use the same OSS bucket. For more information, see Configure express synchronization. Only Standard, Enhanced, and Performance Optimized gateways support the express synchronization feature. The express synchronization feature relies on Simple Message Queue (formerly MNS) and incurs SMQ fees. For more information, see Configure express synchronization.
   Advanced Settings	After you select the Advanced Settings check box, the Advanced Settings step appears.

4. (Optional) In the Advanced Settings step, configure the parameters described in the following table.

   Advanced Settings

   Parameter	Description
   Mode	Select a mode in which you want the share to run. You can select Cache Mode or Replication Mode. By default, a share runs in the cache mode. Replication Mode: In this mode, two backups are created for all data. One backup is stored in the on-premises cache disk and the other backup is stored in the associated OSS bucket. Cache Mode: In this mode, the on-premises cache disk stores only metadata and the data that is frequently accessed. The bucket stores full data. We recommend that you set Mode to Cache Mode if you want to migrate data to the cloud or back up data.
   Transfer Acceleration	Specify whether to enable transfer acceleration. This parameter is available only if you set Cross-region Binding in the Bucket Settings step to Yes. This feature accelerates data transfer across regions by using the public bandwidth of the gateway. Before you use this feature, make sure that the transfer acceleration feature is enabled for the associated OSS bucket.
   Fragmentation Optimization	For applications that frequently and randomly read or write a small amount of data, enabling fragmentation optimization prevents file fragmentation issues of file systems. This feature is an experimental option. You should decide whether to enable this feature based on your actual application requirements.
   Bypass Cache Read	By default, if a cache miss occurs for a read request to a share, the gateway downloads the requested data from the associated OSS bucket to the cache disk. This process involves a certain level of data prefetching. However, if read requests are completely random reads and the size of the cache disk is far smaller than the size of data in the OSS bucket, prefetching data to the cache disk may not deliver satisfactory performance. In this case, consider enabling this feature. We recommend that you enable this feature only when it is necessary.
   Upload Optimization	If you select Yes, cached data is cleared in real time. This feature is suitable for cloud backup scenarios.
   Reverse Sync	Select whether to synchronize metadata of objects in the bucket to your local device. The reverse synchronization feature is useful in scenarios such as disaster recovery, data recovery, and data sharing. Note During a reverse synchronization process, the system scans all objects in the bucket. If there are a large number of objects, you are charged for OSS API calls. For more information, see Pricing. If you select the Add to Sync Group check box in the Basic Information step, the Reverse Sync parameter is unavailable.
   Reverse Sync Interval	If you set Reverse Sync to Yes, you must set the Reverse Sync Interval parameter. Valid values: 15 to 36000. Unit: seconds. Note If the bucket contains a large number of objects, we recommend that you set the interval to be greater than 3,600 seconds. Otherwise, repeated scans result in frequent OSS API calls. This causes an increase in fees generated by OSS API calls.
   Ignore Deletions	If you select Yes, the data that is deleted from the on-premises cache disk is not deleted from the OSS bucket. The bucket stores full data.
   NFS V4 Optimization	Select whether to optimize the upload efficiency if the share is mounted to an NFSv4 file system. If you select Yes, you cannot mount the share to an NFSv3 file system. Note This parameter is available only to an NFS share.
   Sync Latency	Specify a period of time to delay the upload of files. A sync latency prevents frequent on-premises modifications from creating a large number of fragments in OSS. Default value: 5. Maximum value: 120. Unit: seconds.
   Replication Mode Advanced Settings	This parameter is available only if you set Mode to Replication Mode. After you select the Replication Mode Advanced Settings check box, the Replication Mode Advanced Settings step appears.

5. (Optional) In the Replication Mode Advanced Settings step, configure the parameters described in the following table.

   Replication Mode Advanced Settings

   Parameter	Description
   Configure Directory in Replication Mode	Select the directories to which the replication mode applies. If you do not configure directories, the replication mode applies to all data in the share. To configure directories in replication mode, select the check box, click Add Directory, and specify the directories to which you want the replication mode to apply. Directories other than the specified ones use the cache mode. Note If you change the mode of a directory from cache to replication, the files in the directory can be synchronized only when the data download feature is also enabled. We recommend that you enable the data download feature if you use the replication mode. To specify a directory, use its path relative to the mount point of the share. For example, if the directory to which you want to apply the replication mode is /mnt/myshare/mydir/ and the mount point is /mnt/myshare, you can enter /mydir/.
   Data Download	If you enable the data download feature, reverse synchronization or express synchronization synchronizes both data and metadata. If you do not enable the data download feature, only metadata is synchronized. Note Data replication requires the capacity of the cache disk to be greater than 1.1 times the file size to be replicated. Specify the cache capacity based on the expected growth of the bucket usage. The first time you enable the data download feature, a full scan is triggered. This process may affect the performance of the gateway. We recommend that you enable the data download feature during off-peak hours and wait for the system to replicate all the data. The data download feature supports only write-once-read-many storage. If multiple users access the bucket at the same time (including but not limited to direct access or access through the gateway), only one user can upload files to the bucket, and other users can only download data. Data loss may occur if multiple users write data to and read data from the bucket at the same time.
   Download Speed Limit	After you enable data download, you must set this parameter. You can specify a speed limit within the range of 0 MB/s to 1,280 MB/s. If you set this parameter to 0 MB/s, the download speed is unlimited.
   Reverse Sync Interval	Set a reverse synchronization interval. This parameter is available only if you set Data Download to Yes. The reverse synchronization interval ranges from 3,600 seconds to 36,000 seconds. Note If the bucket contains a large number of objects, we recommend that you set the interval to a value greater than 3,600 seconds. Otherwise, repeated scans result in frequent OSS API calls. This causes an increase in fees generated by OSS API calls. Reverse synchronization is triggered only when you access the directory. To make sure that the data in other directories can be downloaded and new data can be downloaded in real time, we recommend that you use express synchronization.

6. In the Confirmation step, check the configuration information. If nothing is wrong, click Completed.