• Configuring file systems

    PDF

    Configuring file systems

    Create a file system

    Before you begin

    Make sure there is a NAS server configured to support the SMB protocol, and that a pool exists with enough available storage space.

    Procedure
    1. Under Storage, select File > File Systems.
    2. Select the Add icon.
    3. On the Protocol window, select Windows Shares (SMB). Then select the associated NAS server.
    4. Optionally click Advanced to select advanced SMB settings.
    5. Continue following the steps in the wizard while noting the following:
      • On the Storage page, the Thin checkbox is selected by default. If you do not want to create a thin file system, remove the checkmark from the Thin checkbox. Removing the checkmark also disables the Data Reduction option.
      • On the Storage page, select the Data Reduction checkbox to enable data reduction on the file system. Data reduction is applied on all new incoming writes. Data that already exists on the file system does not have data reduction applied. Data reduction can be enabled only on thin file systems that reside in All-Flash pools, and only for thin file systems created on Unity systems running OE version 4.2.x or later.
      • On the Shares page, optionally, configure the initial share for the file system.
      • You can configure a snapshot schedule for the file system when you create the file system, or you can do this at a later time.

    Advanced SMB file system settings

    You can set these advanced settings when you change the configuration of an existing SMB-enabled or multiprotocol-enabled file system.

    Setting
    Description
    Sync Writes Enabled
    When you enable the synchronous writes option for a Windows (SMB) or multiprotocol file system, the storage system performs immediate synchronous writes for storage operations, regardless of how the SMB protocol performs write operations. Enabling synchronous writes operations allow you to store and access database files (for example, MySQL) on storage system SMB shares. This option guarantees that any write to the share is done synchronously and reduces the chances of data loss or file corruption in various failure scenarios, for example, loss of power.

    This option is disabled by default.

    The synchronous writes option can have a big impact on performance. It is not recommended unless you intend to use Windows file systems to provide storage for database applications.
    Oplocks Enabled
    (Enabled by default) Opportunistic file locks (oplocks) allow SMB clients to buffer file data locally before sending it to a server. SMB clients can then work with files locally and periodically communicate changes to the storage system rather than having to communicate every operation over the network to the storage system. This feature is enabled by default for Windows (SMB) and multiprotocol file systems. Unless your application handles critical data or has specific requirements that make this mode or operation unfeasible, leaving the oplocks enabled is recommended.

    The following oplocks implementations are supported:

    • Level II oplocks, which informs a client that multiple clients are currently accessing a file, but no client has yet modified it. A level II oplock lets the client perform read operations and file attribute fetches by using cached or read-ahead local information. All other file access requests must be sent to the server.
    • Exclusive oplocks, which informs a client that it is the only client opening the file. An exclusive oplock lets a client perform all file operations by using cached or read-ahead information until it closes the file, at which time the server must be updated with any changes made to the state of the file (contents and attributes).
    • Batch oplocks, which informs a client that it is the only client opening the file. A batch oplock lets a client perform all file operations by using cached or read-ahead information (including opens and closes). The server can keep a file opened for a client even though the local process on the client machine has closed the file. This mechanism curtails the amount of network traffic by letting clients skip the extraneous close and open requests.
    Notify on Write Enabled
    Enable notification when a file system is written to.

    This option is disabled by default.

    Notify on Access Enabled
    Enable notification when a file system is accessed.

    This option is disabled by default.

    Enable SMB Events publishing
    Enable the processing of SMB events for this file system.

    Change file system properties

    If the associated NAS server is a replication destination, many configuration options cannot be changed.

    Procedure
    1. Under Storage, select File > File Systems.
    2. Select the relevant file system, and then select the Edit icon.
    3. On the General tab, change the description of the file system and the file system size. You can also view the file system capacity and free space on this tab.
      If a thin file system was created on a Unity system running OE version 4.1, you can also change the minimum allocation size. You cannot reduce the storage size lower than the current allocation.

      You can enable data reduction for thin file systems created on a Unity system running OE version 4.2.x or later. As data reduction is applied to all new incoming writes to a file system, data reduction statistics (such as data reduction ratio) display on the Properties page.

      If data reduction is enabled and then subsequently disabled, existing data in the file system will remain as is, but newly-written data will not have data reduction applied.

    4. On the Snapshots tab, manage the file system's snapshots or configure a snapshot schedule for the file system.
    5. On the FAST VP tab, change the file system tiering policy and view the data distribution per tier.
    6. On the Advanced tab, optionally do any of the following:
      • Change the advanced SMB properties of a file system.
      • Enable Events Publishing for a file system.
    7. On the Quota tab, configure or change settings for file system quotas and quota trees.
    8. On the Replication tab, configure or change the file system replication settings.
      Replication can be set on the file-system level only if the replication session already exists for the NAS server where the file system resides.

    About Events Publishing

    Events Publishing allows third-party applications to register to receive event notification and context from the storage system when accessing file systems by using the SMB protocol. The Events Publishing agent delivers to the application both event notification and associated context in one message. Context may consist of file metadata or directory metadata that is needed to decide business policy.

    You must define at least one event option (pre-, post-, or post-error event) when Events Publishing is enabled.

    • Pre-event notifications are sent before processing an SMB request.
    • Post-event notifications are sent after a successful SMB request.
    • Post-error event notifications are sent after a failed SMB client request.
    Table 1. Event descriptions
    Value
    Definition
    OpenFileNoAccess
    Sends a notification when a file is opened for a change other than read or write access (for example, read or write attributes on the file).
    OpenFileRead
    Sends a notification when a file is opened for read access.
    OpenFileReadOffline
    Sends a notification when an offline file is opened for read access.
    OpenFileWrite
    Sends a notification when a file is opened for write access.
    OpenFileWriteOffline
    Sends a notification when an offline file is opened for write access.
    OpenDir
    Sends a notification when a directory is opened.
    CreateFile
    Sends a notification when a file is created.
    CreateDir
    Sends a notification when a directory is created.
    DeleteFile
    Sends a notification when a file is deleted.
    DeleteDir
    Sends a notification when a directory is deleted.
    CloseModified
    Sends a notification when a file is changed before closing.
    CloseUnmodified
    Sends a notification when a file is not changed before closing.
    CloseDir
    Sends a notification when a directory is closed.
    RenameFile
    Sends a notification when a file is renamed.
    RenameDir
    Sends a notification when a directory is renamed.
    SetAclFile
    Sends a notification when the security descriptor (ACL) on a file is changed.
    SetAclDir
    Sends a notification when the security descriptor (ACL) on a directory is changed.

    Create Events Publishing notifications

    Before you begin

    Before you can set up Events Publishing for a NAS server:

    • You cannot enable Events Publishing for a NAS server that is acting as a replication destination.
    • At least one file system must exist for the NAS server.
    • You must obtain the IP addresses of the CEPA servers.
    • Ensure that SMB protocol events notifications have been enabled on the File Systems Properties Advanced window.
    Procedure
    1. Under Storage, select File > NAS Servers.
    2. Select the relevant NAS Server, and then select the Edit icon.
    3. On the Protection & Events tab, select the Events Publishing sub-tab.
    4. Select the Enable Common Event Publishing checkbox.
    5. On the New Event Pool window, specify the required items. You must configure at least one event from one of the available categories (pre-event, post-event, or post-error event).
    6. Click Configure.
    7. Click Apply after you finish configuring events.

    About automatic file system shrink and extend

    The system automatically shrinks and extends a thin file system based on capacity needs.

    Thin-provisioned file systems are automatically extended or shrunk by the system when certain conditions are met. Automatic extend prevents the file system from running out of space. Automatic shrink improves space allocation by releasing any unused space back to the storage pool.

    The file system is automatically extended when the used space exceeds 75% of the allocated space.

    The system checks the used-to allocated ratio of the file system every 1.5 hours. If there are five consecutive checks (7.5 hours) where the used-to-allocated ratio remains under 75%, the system initiates an automatic shrink.

    For Unity systems running OE version 4.1.x, you can set a minimum allocated size for a thin file system; automatic and manual shrink operations will not be able to reduce the size of the file system below this minimum. The default minimum allocated size for a thin file system is 3G.

    About manual file storage resource shrink and extend

    You can manually extend or shrink file systems.

    File resource shrink

    The shrink operation reduces the space the file resource uses from the pool, allowing the pool to reclaim the free, unused space from the target file resource.

    For thick-provisioned file resources, you can shrink the size of the resource and return unused space to the pool. For example, if a thick file system is shrunk from a size of 1 TB down to 500 GB:

    • The amount of used space for the resource remains the same.
    • The free space for the resource is reduced by 500 GB.
    • The total pool free space is increased by slightly less than 500 GB.
    • The pool size used for the resource is reduced to approximately 500 GB.

    The system displays a message indicating exactly how much space will be reclaimed by the pool as a result of the shrink operation.

    For thin-provisioned file resources, you can manually shrink the size of a file resource to a size that is equal to or less than the allocated size.

    For Unity systems running OE version 4.1.x, the minimum size of a thin storage resource is 3 GB. You cannot shrink a thin file resource below the size used. For Unity systems running OE version 4.2 or later, the thin file storage resource minimum allocated size option is not supported.
    File resource extend

    The manual extend operation does the following for thin- and thick-provisioned file resources:

    • For thin-provisioned file resources, increases the visible (virtual) size of the resource without increasing the actual size allocated to the resource from the pool.
    • For thick-provisioned file resources, increases the actual space allocated to the resource from the pool.
    You cannot extend a thick file resource beyond the total pool free size.

    Manually shrink or extend the size of a file storage resource

    The ability to manually shrink or extend the size of a storage resource applies to file systems. A manual shrink allows the pool to reclaim space, while a manual extend allocates more space to the storage resource.

    You can cancel a manual shrink operation, but the progress made prior to cancellation will not be reverted.
    Procedure
    1. Select a storage resource, and then click the Edit icon.
    2. In the Size field, enter the new reduced (shrink) or increased (extend) size of the storage resource.
      For Unity systems running OE version 4.1.x, the minimum size of a storage resource is 3 GB. You cannot shrink below the size used or extend beyond the total pool free size.