Quantum StorNext. Product Brief: Distributed LAN Client

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1 Quantum StorNext Product Brief: Distributed LAN Client NOTICE This product brief may contain proprietary information protected by copyright. Information in this product brief is subject to change without notice and does not represent a commitment on the part of Quantum. Although using sources deemed to be reliable, Quantum assumes no liability for any inaccuracies that may be contained in this product brief. Quantum makes no commitment to update or keep current the information in this product brief, and reserves the right to make changes to or discontinue this product brief and/or products without notice. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or information storage and retrieval systems, for any person other than the purchaser s personal use, without the express written permission of Quantum.

2 Executive Summary StorNext, Quantum s next generation data management solution, has been developed to enable rapid file sharing amongst servers and provide cost effective data retention. Initially offered with the release of StorNext 3.0, an advanced data sharing capability was added that allows LAN-based access to StorNext volumes. Termed Distributed LAN Client (DLC), these clients connect to StorNext volumes through clustered gateway systems essentially turning StorNext File System environments into clustered NAS like solutions. Distributed LAN Clients (DLCs) can dramatically lower connectivity costs to StorNext managed storage by applications that do not require direct Fibre Channel SAN access. This is especially attractive to customers with High Performance Computing (HPC) and rendering projects where a large data set is broken into segments and processed by multiple servers. DLC also solves key limitations with NFS and CIFS data sharing through improved resiliency, load balancing and per-stream performance. Methodology Traditional StorNext clients, referred to as SAN Clients, connect directly to a shared SAN storage pool typically via Fibre Channel (FC). Multiple clients can access the storage pool concurrently, so a MetaData Controller (MDC) is required to manage access (see graphic 1). The MDC serves as a traffic cop, handling disk allocation as well as data coherency so that when multiple clients are reading / writing from the same file, they all see the same file content. SAN Clients are ideal for customers that have low latency, high throughput requirements (300s+ MBps to multi-gbps per node performance). For customers that are not bound by high throughput requirements or have a mix of performance requirements, DLC allows LAN-based servers to indirectly connect to shared storage via DLC gateway servers. The DLC gateway servers are StorNext File System (SNFS) SAN Clients that connect directly to the shared storage pool over a FC interface. DLCs are ideal for customers who have farms of servers (rendering, seismic processing, desktop editors, etc.) all needing to access a shared set of files, but not at FC speeds. DLC is also used when customers have a variety of performance needs and want to mix SAN and LAN connectivity (see graphic 2). To access the SAN shared storage, a DLC starts off by communicating with the MDC to determine file location, disk allocation, and permissions the same as a SNFS SAN Client. Once the DLC knows where a file is located, it passes a data request to the DLC gateway server that have direct connectivity to the SAN shared storage. The DLC gateway server then retrieves the data and passes it back to the Distributed LAN Client (see graphic 3). DLC is built using a unique block I/O which increases performance while reducing overhead common with NFS or CIFS transfers. The transfer size of each I/O from the DLC is tunable. The StorNext DLC is capable of up to 1MB of data transferred per each I/O transaction. In contrast, NFS is only capable of 65KB using jumbo frames to increase data transfers per I/O. DLC offers reduced CPU consumption, more efficient data transfers and reduced data fragmentation on the centralized storage disk. Metadata Request StorNext SAN Client MDC Graphic 1: SAN Client Communication Mac Client 1 Client 2 Client 3 Shared Processing UNIX Graphic 2: LAN Client Architecture LAN Clients Retain/ Distribute Metadata Request Clustered Gateway Clustered Gateways High-Speed Ingest MDC Graphic 3: LAN Client Communication Linux StorNext Product Update 2

3 An additional benefit of using DLCs is more efficient data streaming. In the case of video applications, eliminating dropped frames when viewing real-time videos and reducing file fragmentation is paramount. For performance driven applications, DLC delivers the ability to process, modify and analyze data at a much higher rate. DLC is cross-platform capable, making it much more flexible than other block I/O solutions. Many competitive solutions only support one operating system (commonly Linux). StorNext DLC supports mixed LAN attached clients running Linux, Windows and even UNIX (Solaris x86). This eliminates application or server isolation, opening the environment to the most widely used platforms in the industry. It also eliminates the need to NFS/CIFS mount your Windows or Solaris machines; they can participate in the shared high performance DLC environment using LAN-based network infrastructure. Automatic Load Balancing brings additional cost savings and performance with StorNext DLC. No expensive hardware switches or secondary software layers are needed when using StorNext DLC. The MDC monitors the load to each DLC gateway server and will re-allocate requests to balance the system across the available gateway Network Interface Cards (NICs). This eliminates specific DLC gateway servers becoming hot spots where a majority of the I/O is focused on one server while other servers in the environment are not being utilized. DLC environments are further enhanced by automatic failover. If a DLC server should fail, the I/O requests for that server will be re-directed to another active server. This protects the LAN Clients from losing access to their data. Since this process happens automatically, it greatly reduces the administrative load of having to re-map and mount the client machine to a new NFS/CIFS target. This is a feature built-in to StorNext DLC, eliminating the need for extra software or hardware products to provide this level of resiliency. The setup and administration of DLC is simple, flexible and user-friendly. The DLCs are not assigned to specific servers, but LAN Network Interface Cards (NICs). This provides total flexibility and control when establishing a DLC environment. When a DLC mounts the environment, it is presented a list of the active DLCs assigned NIC cards from the multiple DLC gateway servers. The Administrator can select any number of the assigned DLC gateway server NIC cards to be used by the DLCs. The DLC can dynamically use the assigned NICs for its data transfers. If any one of the NICs should fail, the data is dynamically redirected and load balanced across the remaining healthy NIC cards. This failover can happen either on the DLC or DLC gateway server. This allows gateway servers to be added or removed without impacting data I/O, sub-groups of DLCs to be assigned to specific DLC gateway servers, and a level of high availability not possible with standard NFS/CIFS transfers. Implementation Considerations Using Distributed LAN Client with WAN Clients: Metadata operations still pass through the MDC. This communication methodology is suitable for LAN traffic, but not necessarily WAN traffic. On a WAN, latency could be relatively high, because the DLC must first request access via the MDC, wait for the response, and then access data from the DLC gateway server. Therefore, we recommend to evaluate WAN-optimization strategies if DLC is to be used in a WAN environment. For more information on determining latency impacts contact the Quantum Software Architecture Group. Running Additional Applications on the Clustered Gateway: Because the DLC gateway server is a StorNext SAN Client, some customers may be inclined to run applications on the DLC gateway server. Quantum does not recommend this practice. The DLC gateway server is responsible for handling data I/O for multiple Distributed LAN Clients and, at peak load, may need to handle many concurrent I/O streams. The load associated with handling this traffic can be significant, thus generating resource contention. Latency: When determining what applications should utilize DLC, consideration should be given to the throughput required by the application as well as response time. For instance, many production StorNext Product Update 3

4 video applications require a constant data stream with no apparent latency or disruption in data flow. SAN Clients are an excellent choice for these applications because they utilize direct storage connections and deliver the highest possible performance characteristics. DLCs on the other hand, access data over an IP network that is almost always slower than FC and utilize protocols that suffer from latency as client counts increase. In addition, DLCs receive data via a gateway system. This indirect connection is, as with most NAS devices, inappropriate for highest speed, low latency streaming of data. Load Balancing and Resiliency: Load balancing is achieved using various StorNext components. First, large I/Os are sliced up into smaller concurrent I/O requests that are issued across multiple DLC gateway servers, thus increasing throughput by using multiple NICs in parallel. Second, loads are balanced based on queue depth. If the I/O queue to a specific gateway server begins to grow and is not fulfilled quickly, the DLC shifts subsequent I/O to different DLC gateway servers. This mechanism provides for real-time load balancing based on DLC gateway servers latency and throughput. DLC gateway servers that process requests faster will receive more requests from Distributed LAN Clients. On the other hand, when all queues are empty, individual Distributed LAN Clients will pick a single DLC gateway server, selected at random, to service requests. As additional DLC gateway servers are added, Distributed LAN Clients are automatically informed and can start using them for I/O requests. In the event a DLC gateway server becomes unavailable, Distributed LAN Clients will continue to use the remaining DLC gateway servers, allowing for continuous, transparent access to data. I/O that was in progress will be reissued automatically. Clustered Gateways and the MDC: To access data, the DLC must communicate with the MDC to determine where data resides. Once the Distributed LAN Client knows where data is located, it sends a data I/O request to a DLC gateway server. No metadata flows between the Distributed LAN Client and the DLC gateway server. Note that the DLC gateway server may need to contact the MDC during the first access of a file to satisfy Distributed LAN Client I/O. LAN network: Generally, there are no special requirements to use DLC, but it is necessary to have all of the clients on a Gig-e network. A mixed 100base-T and Gig-e network is not supported. TCP offload cards (TOE) and Jumbo frames are not necessary to use DLC. The StorNext Tuning Guide has more detail on the LAN network settings: SoftwareandDocumentationDownloads/SNMS/Index.aspx#Documentation As explained previously, DLC also has the ability to bind or trunk NIC cards for increased aggregate performance. No additional software or hardware is necessary to bind NIC cards. DLC will experience linear performance expansion with the addition of multiple NIC cards. This allows a DLC server or LAN client to increase their performance by utilizing more NIC ports. This is a very inexpensive way to leverage increased performance over NFS or CIFS. Further increases in performance can be obtained by adding additional subnets between the DLC gateways and LAN clients. This allows data to be load balanced amongst the different gateways. The noted performance increase is linear as you add additional subnets. 440 MB/sec has been observed when writing over four dedicated subnets from a single LAN client. It is also possible to use Infiniband networks (IB) with DLC. Customers wanting a lower latency network could elect to use IB over TCP. Max Client Count per DLC Gateway: For the highest level of scalability, Quantum recommends using 64-bit operating systems for the gateway servers. Using 64-bit Windows or Linux enables customers to scale to greater than 1,000 (version 3.5 or higher) LAN Clients. The Software Architecture Group should be consulted to determine the number of gateway servers to implement for a given configuration. StorNext Product Update 4

5 Performance: Distributed LAN Client performance has been verified in various test scenarios. See table for details. Use Cases Thousands of DLCs have been deployed throughout the world interoperating with many different applications and in a wide range of environments. Following are just a few examples: StorNext Client (FC) ~310 MB/s (2 4Gb FC HBA, 4 streams, 2MB Blocksize) Single Proxy Client (Ethernet) Setup 1 ~111 MB/s (1 Proxy Server, 1 1Gb Ethernet) close to physical limit (~90%) Single NFS Client (Ethernet) ~73 MB/s (1 NFS server, 1 1Gb Ethernet) (~59% of physical limit) Single Proxy Client (Ethernet) Setup 2 ~210 MB/s (2 Proxy Servers, 2 1Gb Ethernet) close to physical limit (~84%) DLCs running on render nodes across Infiniband connected to several different StorNext File System clients have experienced nearly 500 MB/sec per node. DLC was used over a 10GB WAN to transfer large files between facilities 40 miles apart. Over one hundred DLCs running on process nodes, each with a single NIC attached to four Gateway Servers (two of which are also MDCs). Both data and StorNext metadata share the same network. Each Gateway Server has four bonded NICs for maximum performance and resiliency. Conclusion Quantum StorNext software delivers a new standard of performance and flexibility. The addition of DLC to StorNext File System further provides customers maximum capability to build data networks that can combine the data sharing capabilities of clustered NAS, DLC and direct FC interconnections. DLC is just one more step in expanding the capabilities of StorNext to customers requiring performance increases over NAS, but without the infrastructure cost of a SAN implementation or the scalability limitation of other clustered NAS solutions. StorNext continues to be a smart investment for performance-minded users who require resilience, scalability and uninterrupted data I/O. Additional Information Summary value of Distributed LAN Client is as follows: Access to StorNext shared storage by LAN-based servers controls costs Fan-out to thousands of clients for true scalability Increased resiliency over NFS or CIFS through transparent path failover and multiple DLC gateway servers. Higher per-stream performance than NFS or CIFS as well as load balancing increases throughput For additional details on how Distributed LAN Client works, available tuning and monitoring parameters, as well as how Distributed LAN Client is used to help customers expand shared storage access, consult your Quantum s Software Sales or Software Architecture Group team member. For more StorNext information, please visit For contact and product information, visit quantum.com, call or send an to softwareinfo@quantum.com Backup. Recovery. Archive. It s What We Do Quantum Corporation. All rights reserved. Quantum, the Quantum logo, and all other logos are registered trademarks of Quantum Corporation or of their respective owners. About Quantum Quantum Corp. (NYSE:QTM) is the leading global storage company specializing in backup, recovery and archive. Combining focused expertise, customer-driven innovation, and platform independence, Quantum provides a comprehensive range of disk, tape, media and software solutions supported by a world-class sales and service organization. This includes the DXi -Series, the first disk backup solutions to extend the power of data deduplication and replication across the distributed enterprise. As a long-standing and trusted partner, the company works closely with a broad network of resellers, OEMs and other suppliers to meet customers evolving data protection needs. PB00021 v2 Mar 2009