Inexpensive Failover Cluster? Easy!

    When it comes to a low-cost cluster solution coupled with the ability to get shared access to drives and pack it all in a 2U form factor, then, at first glance, meeting all three requirements at the same time seems unlikely. But Fujitsu managed to fulfill all these conditions in the PRIMERGY CX420 S1 cluster, which is delivered as a turnkey solution for ensuring the continuity of business applications in small and medium-sized businesses (SMBs), while deprived of the choice of low-cost fault-tolerant solutions.




    Ideology


    It is no secret that companies in the SMB sector usually do not have the ability to hire system administrators with experience in building fault-tolerant systems. Moreover, the activities of many companies are directly related to ensuring the continuity of business processes. For example, dropping the server of an online store for minutes will lead to loss of orders, idle hours will affect reputation, and a day or two of idle time will drastically reduce the attractiveness of a business and may lead to its collapse ... And if a DDoS attack is more efficiently reflected at the provider level, then from a fall The server itself is easier to protect with the help of redundancy, which is taken into account in the server in question.

    The PRIMERGY CX420 S1 is designed as a fail-safe cluster for Windows Server 2012 oriented to use in the SMB segment. Its configuration is available for a system administrator who is familiar with Windows Server and does not require special training. Thus, engineering services can very accurately plan the time, and the finance department - the costs of its implementation. Another feature of the CX420 cluster is that it is a complete solution that does not require a separate external storage system, providing joint access of both server nodes to 12 drives installed in the cluster body, which again reduces implementation costs.

    Architecture


    Fujitsu PRIMERGY CX420 S1 is a two-node cluster running Microsoft Windows Server 2012. Actually, the CX420 S1 is a 2U chassis in which two server nodes are installed. Each node is a PRIMERGY CX272 S1 server, including a pair of modern (up to 8-core) Intel Xeon E5-2600 processors (CPUs from E5-2603 to E5-2680 are supported). The processor supports four-channel data exchange with memory; in total, each node allows you to install 16 modules with a capacity of up to 16 GB, which gives a maximum of 256 GB of RAM per node.




    In addition to two external gigabit network ports, each server has a service LAN port and three PCIe slots, one of which must have SAS-expander installed. The CX272 S1 server has up to two internal bootable SATA disks (without hot swapping, with the ability to mirror) and a SAS connection to shared drives located in the chassis of the CX420 chassis. Drives (up to 12 pcs.) Have a 3.5-inch form factor, however it is possible to use the same number of 2.5-inch drives in special adapters for a 3.5-inch slot.

    Shared drives give the first unique properties of the cluster in question. All 12 dual-port cluster drives are combined into a single disk space using Windows Storage Spaces technology. The presence of two ports provides simultaneous access to space from both nodes. If necessary, this disk space can be expanded by connecting an additional two-port external JBOD array to 12 SAS disks.

    The nodes have a height of 2U and are located horizontally relative to each other. Between them in the chassis is a central compartment containing fans and hot-swappable power supplies. The nodes are interconnected by a gigabit Ethernet channel (implemented on the backplane inside the chassis). This channel is used to synchronize the cluster (“heartbeat”). The ventilation system generates two independent air flows through both nodes and expels air through the central unit back. The nodes themselves are fanless and packageless, which, incidentally, allowed to reduce the cost of the system. The power consumption of the cluster is no more than 1200 watts.

    Thus, the entire cluster fits in a standard 2U rack and does not require special conditions for power supply and cooling.

    Readiness


    High availability requires hardware and software redundancy. The hardware redundancy in the Fujitsu PRIMERGY CX420 S1 is provided by duplication of compute nodes, each of which allows for hot swapping. In addition, on-the-fly power supplies can be replaced. As mentioned above, the synchronization of cluster nodes is organized through a gigabit Ethernet channel, which is located on the backplane. Depending on the scenario, when one of the nodes is disconnected, either the entire load is transferred to another node without delay in operation, from the point of view of the user, or failover is performed for a short time to start tasks from the failed active node on the passive backup node. Moreover, failover is supported both for native applications and those working in a virtual environment. SAS adapters on the board do not require the use of RAID, since the work of shared disk space is organized by means of Windows 2012 Storage Spaces. This technology provides a number of advantages compared to traditional RAID systems, representing something more likely closer to WAFL from Netap than just “spreading” data across RAID group disks. In particular, it provides thin provisioning: you can fine-tune the use of various disks from those in the cluster. This is especially true if different types of drives are used. than just “smudging” data across RAID group disks. In particular, it provides thin provisioning: you can fine-tune the use of various disks from those in the cluster. This is especially true if different types of drives are used. than just “smudging” data across RAID group disks. In particular, it provides thin provisioning: you can fine-tune the use of various disks from those in the cluster. This is especially true if different types of drives are used.



    You can see about the capabilities of Storage Spaces on the cluster here , and about the configuration here .

    Total


    “In the face” of the Fujitsu PRIMERGY CX420 S1, users get a compact (2U) and low-cost high-availability cluster with shared storage, without having to use external storage. In addition to saving on the equipment itself, the partner will be able to save on maintenance, since the system is designed to work under Windows Server 2012. It will not require special knowledge in the field of fault tolerance and clustering from the engineers serving it.
    At the same time, the Fujitsu PRIMERGY CX420 S1 is made for use in standard server racks and is designed for traditional air cooling without additional requirements (and therefore without costs) to the infrastructure.

    ***

    FAQ


    This cluster was presented to our partners a little earlier at the Fujitsu Server Cluster PRIMERGY CX420 S1 webinar , so we wanted to immediately answer the typical questions that the audience asked our employee Pavel Borokh, product marketing manager, PRIMERGY servers in Russia and the CIS countries.

    1) Alternative operating systems
    It is possible to use operating systems other than Windows Server 2012 only through virtualization using Hyper-V. Programs that will work in a virtual environment, too, will be restored after failover.

    2) Differences from other Fujitsu servers.
    For example, we have put together an alternative system with support for 12 SAS disks with a capacity of 900 GB and duplication functions.



    When using two single-server PRIMERGY RX200 S7 servers and ETERNUS DX60 S2 disk storage, as you can see in the picture, it took up more rack space, has more consumption, and most importantly - it costs 32,300 euros instead of 26,530 euros for the Fujitsu PRIMERGY CX420 S1. This does not mean that we picked up a poor set of servers and storage systems, just the CX420 S1 meets the stated goals as accurately as possible - a compact high-availability server with standard infrastructure requirements.
    Please note that the prices above are European List Price. To find out the cost in Russia, you need to contact our partners.

    3) Differences from other 2U clusters
    We do not pretend to be exclusive in design - two servers and a connecting unit in the 2U form factor. However, for example, servers from other manufacturers make it possible to assemble a cluster for high-performance computing in this volume, while the CX420 is designed to build a cluster for high reliability, with built-in recovery procedures in case of failure.

    4) The development potential of the
    PRIMERGY CX420 S1 is one of a number of planned ready-made solutions from Fujitsu for Microsoft software. Soon we will also present ready-made solutions (“appliances”) for Microsoft SQL Server and Sharepoint Server.

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