Multi-Path I/O - End to End High Availability and Performance

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MULTI-PATH I/O - END TO END HIGH AVAILABILITY AND PERFORMANCE
Why MPIO? Most IT administrators recognize the inherent value of RAID - by redundantly storingBecause most storage data you protect information from infrastructure failures and provide continuous access.devices support multiple Most storage devices support multiple SAN connections for performance and SAN connections for per- reliability, but in many configurations servers use only a single storage connection. formance and reliability. This creates a single point of failure and potential performance bottleneck for I/O. Multi-MPIO provides multiple path Input/Output (MPIO) is server software that extends redundancy to the entire I/Opaths from servers to pathway in a SAN, delivering fault tolerance, high availability, and better performance. storage, delivering fault tolerance, high availability, MPIO DEPENDS ON SEVERAL ARCHITECTURAL FEATURES:and better performance. . The storage array must be MPIO capable, with multiple interfaces that allow multiple concurrent connections to data.. Storage must be redundant andhot serviceable.. The hosts must have multiple con-nections into the SAN, plus MPIOsoftware to create and manage theconnections in a manner consistentwith the operating system.. Redundant, high-bandwidth network switches are required.
SAFER, FASTER, MORE AVAILABLE MPIO uses redundant connections todeliver high availability - having multi-ple host connections, multiple switches, and multiple storage interfaces eliminates allsingle points of failure, so data flow can continue despite any component malfunction.With a single connection or data path, any network component, switch, or storage failure results in work stoppage.
MPIO can also enhance performance - by concurrently using multiple data paths,applications gain throughput. MPIO on the host load balances I/O requests over theexpanded host connectivity (with multiple NICs, TOEs, or HBAs) into the SAN. I/Otravels over many paths simultaneously for improved performance and lower latency. MPIO CHOICES SAN PATH BALANCING - AN MPIO IMPLEMENTATIONThe two primary forms of MPIO are network-based and stor- CHALLENGEage-based. Network-based MPIO offers failover and load In SAN configurations, many connections from host tobalancing, but has configuration and operational limitations switches feed into fewer connections from switches to and requires special network setup. It only supports software storage. It is common for 10 hosts to be connected to a initiators with NICs or TOEs, not HBAs. Network and switch single storage array through the SAN; this can be a naturalconfigurations are restricted, and certain network manage- bottleneck. But with MPIO, you can manage the paths inment features must be disabled. Since these solutions load both halves of your architecture - from server to switch andbalance using random I/O distribution with no awareness of from switch to storage - eliminating the congestion. link status, network operations are less efficient. For optimal operation, all network paths between the hostStorage-based MPIO offers and the storage must be balanced. Multi-path software onNetwork-based MPIO delivers a more powerful, flexible, and the host handles the host-to-switch connection, but how aresome failover and load balancing, efficient solution, and works the switch-to-storage connections balanced? In many solu-but is more complex to set up andmanage. Storage-based MPIO with any mix of NICs, TOEs, tions this is a manual task, which increases the administrativeoffers more advanced functionality and HBAs. This method burden and decreases operational efficiency. It is also a jobwith fewer restrictions. requires no special setup or that is never complete, as workloads change constantly. network configuration - ahost can leverage multiple PS SERIES ARRAYS ADDS AUTOMATION FOR MPIOconnections to any number of storage devices. This solution ENVIRONMENTSalso supports a rich variety of load balancing algorithms, PS Series arrays simplify multi-path management by automat-including active-active, minimum queue, active-passive, ically monitoring and load balancing I/O across multiple hostfastest response time, etc. and storage connections - online, continuously, without disrupting servers. Intelli... [download for more]