Creating and managing file systems using GUI
You can create, view, and
modify file systems.
A file system consists of a set of disks that are used to store file metadata as well as data and
structures, including quota files and recovery logs. The file system achieves high performance I/O
in the following ways:
- Stripes data across multiple disks that are attached to multiple nodes:
- All data in the file system is read and written in wide parallel stripes.
- The block size for the file system determines the size of the block writes.
- The block size that is specified at the time of file system creation, is global across the file system, and cannot be changed after the file system is defined
- Optimizes for small block write operations; a block is also
subdivided into subblocks, so that multiple small block application writes can be aggregated and
stored in a file system block, without wasting space in the block.
- Provides a high performance metadata (inode) scan engine to scan the file system rapidly to enable fast identification of data that needs to be managed or migrated in the automated tiered storage environment.
- Supports a large block size that can be configured by the administrator to fit I/O requirements:
- Typical block sizes are the default (4 MiB), which is suitable for
most workloads, especially mixed small random and large sequential workloads.
- For large sequential workloads, the file system can optionally be defined with block sizes up to 16 MiB.
- Uses advanced algorithms that improve read-ahead and write-behind file functions for caching.
- Uses block-level locking based on a sophisticated token-management system that provides data consistency, while allowing multiple application nodes concurrent access to the files.
Creating and deleting file system
Use the Create File System
option available in the page to create file systems.
Deleting a file system removes all of the data on that file system. Use caution when performing this task. To delete a file system, select the file system to be deleted and then select Delete from the Actions menu.
File system monitoring options
The File Systems page provides an easy way to monitor the performance, health status, and configuration aspects of the all available file systems in the IBM Spectrum Scale™ cluster.
The following options are available to analyze the file system performance:
- A quick view that gives the number of protocol nodes, NSD servers, and NSDs that are part of the
available file systems that are mounted on the GUI server. It also provides overall capacity and
total throughput details of these file systems. You can access this view by selecting the expand
button that is placed next to the title of the page. You can close this view if not required. The graphs displayed in the quick view are refreshed regularly. The refresh intervals are depended on the displayed time frame as shown below:
- Every minute for the 5 minutes time frame
- Every 15 minutes for the 1 hour time frame
- Every six hours for the 24 hours time frame
- Every two days for the 7 days time frame
- Every seven days for the 30 days time frame
- Every four months for the 365 days time frame
- A file systems table that displays health status, performance details, and other important
configuration aspects of file systems available in the system. The following important details are
available in the file system table:
- File systems configured in the system
- Health status. The detailed information about the events reported against each file system are available in the Events tab of the file system detailed view.
- Capacity information
- Certain information of remote file systems that are mounted from a remote cluster.
- Mount status, mount configuration, and number of local and remote mounts. .
- Number of pools that are part of the file system. A file system consists of one or more pools. Detailed information of pools of a file system are available in the Pools tab of the file system detailed view.
- Number of NSDs that are part of the file system. Detailed information of NSDs of a file system are available in the NSDs tab of the file system detailed view.
- Performance data. To find file systems with extreme values, you can sort the values displayed in the file systems table by different performance metrics. Click the performance metric in the table header to sort the data based on that metric. You can select the time range that determines the averaging of the values that are displayed in the table and the time range of the charts in the overview from the time range selector, which is placed in the upper right corner. The metrics in the table do not update automatically. The refresh button above the table allows to refresh the table with more recent data. The detailed performance details per node, pool, and NSDs are available in the detailed view of the file system.
- Protocols that are used to export or share the data stored in the file system.
- Number of nodes on which the file system is mounted. Details specific to each node on which the file system is mounted are available in the detailed view of the file system. You can also mount or unmount the file system from the detailed view.
- A detailed view of the performance and health aspects of individual file systems. To see the
detailed view, you can either double-click on the file system for which you need to view the details
or select the file system and click View Details. The detailed performance view helps to drill-down to various performance aspects. The following list provides the performance details that can be obtained from each tab of the performance view:
- Overview: Provides an overview of the file system performance.
- Events: System health events reported for the file system.
- NSDs: Details of the NSDs that are part of the file system.
- Pools: Details of the pools that are part of the file system.
- Nodes: Details of the nodes on which the file system is mounted.
- Filesets: Details of the filesets that are part of the file system.
- NFS: Details of the NFS exports created in the file system.
- SMB: Details of the SMB shares created in the file system.
- Object: Details of the IBM Spectrum Scale object storage on the file system.
- Properties: Provides details of the file system attributes. You can also utilize the Automatic mount option to configure the automatic mount mode of the file system.
Managing access control
You can control the access to files and directories in a file system by defining access control lists (ACLs). ACLs can be inherited within a file system. The link path of the file system does not inherit any ACL from a parent path. Therefore, you can set the ACL of the file system link path using the Edit Access Control option.
When creating a file system, a default ACL is set. To modify the access controls defined for a file system, right-click the file system that is listed in the file system view and select Edit Access Control. The owner, owning group, and access control list cannot be modified if the directory is not empty. Users with the role Dataaccess are allowed to modify owner, group, and ACL even when the directory is not empty.
Mounting or unmounting a file system
You can use the IBM Spectrum Scale GUI to mount or unmount individual file systems or multiple file systems on the selected nodes. Use the , , or page in the GUI to mount or unmount a file system.
The GUI has the following options related to mounting the file system:
- Mount local file systems on nodes of the local IBM Spectrum Scale cluster.
- Mount remote file systems on local nodes.
- Select individual nodes, protocol nodes, or nodes by node class while selecting nodes on which the file system needs to be mounted.
- Prevent or allow file systems from mounting on individual nodes. Do the following to prevent file systems from mounting on a node:
- Go to .
- Select the node on which you need to prevent or allow file system mounts.
- Select Prevent Mounts from the Actions menu.
- Select the required option and click Prevent Mount or Allow Mount based on the selection.
- Configure automatic mount option. The automatic configure option determines whether to
automatically mount file system on nodes when GPFS daemon starts or when the file system is accessed
for the first time. You can also specify whether to exclude individual nodes while enabling the
automatic mount option. To enable automatic mount, do the following:
- From the page, select the file system for which you need to enable automatic mount.
- Select Configure Automatic Mount option from the Actions menu.
- Select the required option from the list of automatic mount modes.
- Click Configure.
Note: You can configure automatic mount option for a file system only if the file system is unmounted from all nodes. That is, you need to stop I/O on this file system to configure this option. However, you can include or exclude the individual nodes for automatic mount without unmounting the file system from all nodes.
You can utilize the following unmount features that are supported in the GUI:
- Unmount local file system from local nodes and remote nodes.
- Unmount a remote file system from the local nodes. When a local file system is unmounted from the remote nodes, the remote nodes can no longer be seen in the GUI. The page lists the remote nodes that currently mount the selected file system. The selected file system can be a local or a remote file system but the GUI permits to umount only local file systems from the remote nodes.
- Select individual nodes, protocol nodes, or nodes by node class while selecting nodes from which the file system needs to be unmounted.
- Specify whether to force unmount. Selecting the Force unmount option while unmounting the file system unmounts the file system even if it is still busy in performing the I/O operations. Forcing the unmount operation affects the outstanding operations and causes data integrity issues. The IBM Spectrum Scale system relies on the native unmount command to carry out the unmount operation. The semantics of forced unmount are platform-specific. On certain platforms such as Linux, even when forced unmount is requested, file system cannot be unmounted if it is still referenced by system kernel. To unmount a file system in such cases, identify and stop the processes that are referencing the file system. You can use system utilities like lsof and fuser for this.
Some administrative actions like repairing file system structures by using the mmfsck command, require that the file system is unmounted on all nodes.
Policies
IBM Spectrum Scale provides a way to automate the management of files by using policies and rules. You can manage these policies and rules through the page of the management GUI.
A policy rule is an SQL-like statement that tells the file system what to do with the data for a file in a specific pool if the file meets specific criteria. A rule can apply to any file being created or only to files being created within a specific fileset or group of filesets.