Dell PowerFlex Appliance with PowerFlex 4.x Architecture Overview

PowerFlex file architecture

PowerFlex file is deployed on PowerFlex file nodes to provide file services to applications.

PowerFlex file nodes provide compute capabilities (CPU and memory) and consume storage from PowerFlex block (SDS) providing a highly scalable performance for transactional and traditional workloads. PowerFlex file can be scaled independently of PowerFlex storage providing more flexible options for customers.

The following figure highlights applications consuming PowerFlex file storage:

With the native file capabilities available on PowerFlex appliance, administrators can easily implement a highly scalable, efficient, high performance, and flexible solution that is designed for the modern data center. The rich supporting feature set and mature architecture provides the ability to support a wide array of use cases. PowerFlex file uses virtualized NAS servers to enable access to file systems, provide data separation, and act as the basis for multi-tenancy. PowerFlex file services can be accessed through a wide range of protocols and can take advantage of advanced protocol features.

• PowerFlex file servers - PowerFlex file uses virtualized file servers that are called NAS servers. A NAS server contains the configuration, interfaces, and environmental information that is used to facilitate access to the file systems. This includes services such as Domain Name System (DNS), Lightweight Directory Access Protocol (LDAP), Network Information Service (NIS), protocols, anti virus, NDMP, and so on.
• Multi-tenancy - NAS servers can be used to enforce multi-tenancy. This is useful when hosting multiple tenants on a single system, such as for service providers. Since each NAS server has its own independent configuration, it can be tailored to the requirements of each tenant without impacting the other NAS servers on the same appliance. Each NAS server is logically separated from each other, and clients that have access to one NAS server do not inherently have access to the file systems on the other NAS servers. File systems are assigned to a NAS server upon creation and cannot be moved between NAS servers.
• High availability - New NAS servers are automatically assigned across the available nodes. The preferred node acts as a marker to indicate the node that the NAS server should be running on. Once provisioned, the preferred node for a NAS server never changes. The current node indicates the node that the NAS server is running on. Changing the current node moves the NAS server to a different node, which can be used for load-balancing purposes. When a NAS server is moved to a new node, all file systems on the NAS server are moved along with it.
• Protocols - PowerFlex file supports SMB1 through 3.1.1. SMB3 enhancements such as continuous availability, offload copy, protocol encryption, multichannel, and shared VHDX in Hyper-V are supported on PowerFlex file. PowerFlex file also supports the Microsoft Distributed File System (DFS) namespace. This ability enables the administrator to present shares from multiple file systems through a single mapped share. PowerFlex file SMB servers can be configured as a stand-alone DFS root node or as a leaf node on an Active Directory DFS root. DFS-R (replication) is not supported on PowerFlex file SMB servers.

  PowerFlex file supports NFSv3 through NFSv4.1 and as Secure NFS. Each NAS server has options to enable NFSv3 and NFSv4 independently. Support for advanced NFS protocol options is also available. NFSv4 is a version of the NFS protocol that differs considerably from previous implementations. Unlike NFSv3, this version is a stateful protocol, meaning that it maintains a session state and does not treat each request as an independent transaction without the need for additional preexisting information NFSv4 brings support for several new features including NFS ACLs that expand on the existing mode-bit-based access control in previous versions of the protocol.

  NAS servers and file systems also support access for FTP and SFTP. SFTP is more secure since, it does not transmit usernames and passwords in clear text. FTP and SFTP access can be enabled or disabled individually at the NAS server level. Only active mode FTP and SFTP connections are supported.

• Multi-protocol support - When a NAS server has both the SMB and NFS protocols enabled, multi-protocol access is automatically enabled. Multiprotocol access enables accessing a single file system using the SMB and NFS protocols simultaneously.
• Naming and directory services - PowerFlex file supports the following naming and directory services:
  • DNS - A service that provides translations between hostnames and IP addresses
  • LDAP/NIS - Services that provide a centralized user directory for username and ID resolution
  • Local files - Individual files used to provide username and ID resolution
• Filesystem - PowerFlex file leverages a 64-bit file system that is highly scalable, efficient, performant, and flexible. The PowerFlex file is mature and robust, enabling it to be used in many of the traditional NAS use cases.
• Compression - PowerFlex file supports compression using fine granularity storage pools.
• Shrink and extend - PowerFlex file provides increased flexibility by providing the ability to shrink and extend file systems as needed. Shrink and extend operations are used to resize the file system and update the capacity that is seen by the client.
• Quotas - PowerFlex file includes quota support to allow administrators to place limits on the amount of space that can be consumed to regulate file system storage consumption. PowerFlex file supports user quotas, quota trees, and user quotas on tree quotas. All three types of quotas can co-exist on the same file system and can be used together to achieve fine grained control over storage usage.
  • User quotas: User quotas are set at a file system level and limit the amount of space a user may consume on a file system. Quotas are disabled by default.
  • Tree quotas: Quota trees limit the maximum size of a directory on a file system. Unlike user quotas, which are applied and tracked on a user-by-user basis, quota trees are applied to directories within the file system. Quota trees can be applied on new or existing directories.
  • User quotas on tree quotas: Once a quota tree is created, it is also possible to create additional user quotas within that specific directory by choosing to enforce user quotas. When multiple limits apply, users are bound by the limit that they reach first.
• Snapshots - PowerFlex file features pointer-based snapshots. These can be used for restoring individual files or the entire file system back to a previous point in time. Since these snapshots leverage redirect-on-write on technology, no additional capacity is consumed when the snapshot is first created. Capacity only starts to be consumed as data is written to the file system and changes are tracked.
• CAVA - Common Anti-Virus Agent (CAVA) provides an ant virus solution to SMB clients by using third-party anti virus software to identify and eliminate known viruses before they infect files on the storage system. Windows clients require this to reduce the chance of storing infected files on the file system and protects them if they happen to open an infected file. The CAVA solution is for clients running the SMB protocol only. If clients use the NFS or FTP protocols to create, modify, or move files, the CAVA solution does not scan these files for viruses.
• NDMP - PowerFlex file supports three-way Network Data Management Protocol (NDMP) backups, allowing administrators to protect file systems by backing up to a tape library or other backup device. In an NDMP configuration, there are three primary components:
  • Primary system - Source system to be backed up, such as PowerFlex file.
  • Data Management Application (DMA) - Backup application that orchestrates the backup sessions, such as NetWorker.
  • Secondary system - The backup target, such as PowerProtect.

  Three-way NDMP transfers both the metadata and backup data over the network. The metadata travels from the primary system to the DMA. The data travels from the primary system to the DMA and then finally to the secondary system.

• Global NameSpace - Global NameSpace also known as single namespace provides users a virtual view of shared folders by grouping shares/exports located on different servers into one or more single entry point to access multiple-filesystems. With Global NameSpace feature enabled, client hosts with correct access permission would be able to access existing and newly added FS to the Global NameSpace without needing to explicitly map/mount it on each client. Powerflex file supports multi-protocol Global NameSpace (GNS) for both SMB and NFSv4 clients. NFSv3 clients are not supported by the Global NameSpace infrastructure however they can access the shares directly.
• Common Event Publishing Agent (CEPA) - The Dell Common Event Enabler (CEE) framework is used to provide a working environment for the Common Event Publishing Agent (CEPA) facility, which includes sub-facilities for auditing, content/quota management (CQM), Common Asynchronous Publishing Service (VCAPS), and indexing. CEE Common Event Publishing Agent (CEPA) is a mechanism whereby applications can register to receive event notification and context from Powerflex file system. The event publishing agent delivers to the consuming 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
• NAS Server and Filesystem Clone - Powerflex file users can clone their NAS server and filesystem for environment repurposing.
• File-level retention - File-level retention protects files from modification or deletion until a specified retention period. Protecting a file system using File-level retention enables you to create a permanent, and unalterable set of files and directories. File-level retention ensures data integrity and accessibility, simplifies archiving procedures for administrators and improves storage management flexibility.