Best Practices For Designing, Deploying, And Administering .

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Best Practices for designing,deploying, and administeringSAN using EMC CLARiiONStorage SystemsAnuj SharmaEMC Proven Professional Knowledge Sharing 2010Anuj

TABLE OF CONTENTSS.NONAME OF THE TOPICI.AbstractPAGENO.4-5II.III.IV.Executive SummaryIntroductionEssentials6-91011-13A. Designing SAN1. Topology ConsiderationsSAN TopologiesInformation GatheringChoosing a Switch TypeSample SAN FabricB. Implementation Phase1. and Zoning Best PracticesIP SAN Best PracticesRAID Group Best PracticesHBA TuningHot Sparing Best PracticesOptimizing CacheVault Drive Best PracticesVirtual Provisioning Best PracticesDrive Spin Down TechnologyAligning File SystemC. Post Implementation PhaseHealth CheckupPerformance Monitoring2010 EMC Proven Professional Knowledge 838-39394040-4343-4444-454545-4849-522

LIST OF UniverseSAN FeaturesDeployment PhasesSingle Switch TopologyFull Mesh TopologyPartial Full Mesh TopologyCore Edge FabricSAN FABRICExecution Throttle Change SnapshotExtop screenshotExtop screenshotChanging Queue DepthThin ProvisioningCreating Storage PoolsDisk Drive Spin DownDisk CrossingDAE CheckupLCC CheckupDisk Module CheckupDAE CheckupSPE CheckupSPE CheckupNavisphere AnalyzerNavisphere 4848.4950LIST OF TABLES1.Single Switch Subjective Rating172.Full Mesh Switch Subjective Rating183.Partial Mesh Switch Subjective Rating204.Core Edge Subjective Rating215.IOPS Requirements236.Switch Case Scenario247.64 Switch Case Scenario258.Increased ISLs between core and edge switches259.HBA Tuning Parameters3510.Hot Spare Provisioning Example4011.Cache Recommendations4012Vault Drive Recommendations4013.Data Center Environment Requirements48.2010 EMC Proven Professional Knowledge Sharing3

I.ABSTRACTIf your Windows or UNIX networks are expanding to keep pace with a growing business, youneed more than simple, server-based information storage solutions. You need an enterprisecapable, fault-tolerant, high-availability solution and EMC CLARiiON products are theanswer. CLARiiON storage systems employ the industry’s most extensive set of data integrityand data availability features, such as dual-active storage processors, mirrored write caching,data verification, and fault-recovery algorithms and support complex cluster configurations,including Oracle and Microsoft software. CLARiiON data storage solutions have long beenrecognized as the most robust and innovative in the industry. Features of CLARiiON systemsinclude: Flash drives UltraFlex technology Fibre Channel/iSCSI connectivity Virtual provisioning Tiered storage Virtualization-aware management Virtual LUN technology Drive Spin-Down TechnologyThe performance and flexibility of CLARiiON storage systems has to be backed by superioravailability. This is where CLARiiON really shines. Its design has no single point of failure, allthe way down to the fans and power cords.This paper includes the practices that I follow and recommend to realize the benefit ofCLARiiON’s features and optimally utilize its resources to maximize performance; from initialsolution design, to implementation, to SAN administration.When thinking of designing a SAN, there are many important things that you need to considerbefore you jump right into it. For starters, you need to know how the components fit togetherin order to choose a SAN design that will work for you. Like most storage managers, you'llwant to design your SAN to fit today's storage needs as well as meet tomorrow's increasedstorage capacity requirements. Aside from being scalable, the ideal SAN should also bedesigned for resiliency and high availability with the least amount of latency. This article willtouch the following topics:Initial SAN Solution Designing2010 EMC Proven Professional Knowledge Sharing4

SAN topologies to be considered for different SAN deploymentsZoning Best PracticesPractices that should be followed while implementing the SANUsing thin provisioning the best way it should beHow Thin provisioning brings utilization and capacity benefitsVMware ESX Server using EMC CLARiiON storage systems. and many moreThis article will benefit anyone who implements, manages, or administers SAN using EMCCLARiiON storage systems.2010 EMC Proven Professional Knowledge Sharing5

II.Executive SummaryAs an enterprise grows and evolves, the data of the organization grows exponentially alongwith data storage requirements. Meeting legal and organizational compliance requirementshas become more difficult as data retention periods have been extended. To avoid futuretrouble, organizations have started following compliance more seriously.According to an IDC survey, by 2011, the digital universe will be 10 times its size in 2006.The diversity of the digital universe can be seen in the variability of file sizes, from sixgigabyte movies on DVD to 128-bit signals from RFID tags. Because of the growth of VoIP,sensors, and RFID, the number of electronic information “containers” — files, images,packets, tag contents — is growing 50% faster than the number of gigabytes. The informationcreated in 2011 will be contained in more than 20 quadrillion — 20 million billion — of suchcontainers, a tremendous management challenge for both businesses and consumers.Meanwhile, media, entertainment, and communications industries will account for 10 timestheir share of the digital universe in 2011 as their portion of worldwide gross economic output.The picture related to the source and governance of digital information remains intact:approximately 70% of the digital universe is created by individuals, but enterprises areresponsible for the security, privacy, reliability, and compliance of 85%. So the requirementsof storage media is increasing two fold, day by day.Figure 1 Digital Universe2010 EMC Proven Professional Knowledge Sharing6

DAS and NAS implementations allow companies to store and access data effectively, butoften inefficiently. This leads to the isolation of storage to the specific devices, making itdifficult to manage and share. Storage area networks (SANs) have the advantage ofcentralization, resulting in improved efficiencies. A SAN is a dedicated storage network thatsolves many of the complex business data storage needs. Fiber Channel Switches enableincreased connectivity and performance allowing for interconnected SANs and ultimately,enterprise-level data accessibility of SAN applications and accessibility.As SANs continue to grow, many factors need to be considered to help scale and managethem. A SAN should be designed with present and future needs in mind. A SAN should bedesigned keeping in mind the Datacenter Manager needs.For example: 24X7 Data Availability Flexible Architecture Resilient and Robust Architecture Cost Effectiveness Hassle-Free Information Management Scalable Infrastructure Optimally catering to the bandwidth requirements of different applicationsFigure 2 SAN FEATURES2010 EMC Proven Professional Knowledge Sharing7

The storage system is the most important part in a SAN. The speed and efficiency with whichstorage arrays can respond to I/O requests from the servers is critical for minimizingtransaction response times.In addition to speed and efficiency, the storage system should meet the followingcritical requirements: Availability – Ensure that data is accessible at all times when needed. Loss of access todata can have significant financial impact on businesses. Security – Prevent unauthorized access to data. Mechanisms to allow servers to accessonly their allocated resources on storage arrays. Capacity – Ability to add storage capacity “on-demand”, without interruption to thebusiness. If a database runs out of physical storage space, it comes to a halt, thus impactingthe business. Scalability – The storage solution should be able to grow with the business. As thebusiness grows, more servers are deployed and new applications/databases developed. Performance – Service all the I/O requests at high speed. With the centralized model,several servers connect to one storage array. The intelligence of the array, the processors,and architecture should enable optimal performance. Data Integrity – Throughout the I/O chain, checks have to be in place to ensure that data isnot corrupted along the way. The storage system has to “guarantee” that the data that wassent to it was indeed the data that was written to disk and is available for retrieval whenrequested. Manageability – The operations and activities required to meet all of these requirementsshould be performed seamlessly and with minimal disruption to business activity.Also, a 2006 IDC study found that power and cooling costs are escalating rapidly as newer,denser servers and storage come online. Customers building new data centers are planningfor “Green IT”, a hot topic in IT circles. Today’s storage systems should have the intelligenceto use power wisely. EMC CLARiiON addresses this concern with the new Drive Spin Downtechnology. While CLARiiON – as an Intelligent Storage System – meets all the above criticalrequirements, it may not always meet all the requirements of an administrator unless some ofthe practices are followed at the pre-implementation and implementation phases. There are2010 EMC Proven Professional Knowledge Sharing8

practices that we should follow while implementing a SAN that maximize resource utilizationand optimize storage system performance.2010 EMC Proven Professional Knowledge Sharing9

III.INTRODUCTIONThis paper focuses on large IP-SAN or FC-SAN deployments within a data center, andprovides best practices and design considerations when designing a reliable and efficientSAN using EMC CLARiiON storage systems.This paper comprises the following 3sections:Figure 3 PhasesDesigning SANImplementing SANAdministering SANEach section comprises best practices that I feel should be followed at different stages ofSAN deployment to optimally utilize the available resources. Having top-of-the-line SANequipment does not guarantee optimal performance. We need to focus on certain parameterswhile designing, implementing, and administering a SAN to get optimal performance out ofthe available resources.Apart from best practices, this paper will also focus on the features that enable EMCCLARiiON storage systems to stand tall among the competitors.2010 EMC Proven Professional Knowledge Sharing10

IV. ESSENTIALSDomain IDA byte-wide field in the three byte Fibre Channel address that uniquely identifies a switch in afabric. The three fields in a FCID are domain, area, and port. A distinct Domain ID isrequested from the principal switch. The principal switch allocates one Domain ID to eachswitch in the fabric. A user may be able to set a Preferred ID which can be requested of thePrincipal switch, or set an Insistent Domain ID. If two switches insist on the same DID one orboth switches will segment from the fabric.Director SwitchesAn enterprise-class Fibre Channel switch, such as the Connectrix ED-140M, MDS 9509, orED-48000B. Directors deliver high availability, failure ride-through, and repair under power toinsure maximum uptime for business-critical applications. Major assemblies, such as powersupplies, fan modules, switch controller cards, switching elements, and port modules, are allhot-swappable. The term director may also refer to a board-level module in the Symmetrix that provides the interface between host channels (through an associated adapter module inthe Symmetrix) and Symmetrix disk devices. Interswitch link (ISL) a physical E Portconnection between any two switches in a Fibre Channel fabric. An ISL forms a hop in afabric.HBAA bus card in a host system that allows the host system to connect to the storage system.Typically, the HBA communicates with the host over a PCI or PCI Express bus and has asingle Fibre Channel link to the fabric. The HBA contains an embedded microprocessor withon-board firmware, one or more ASICs, and a Small Form Factor Pluggable module (SFP) toconnect to the Fibre Channel link.FabricOne or more switching devices that interconnect Fibre Channel N Ports, and route FibreChannel frames based on destination IDs in the frame headers. A fabric provides discovery,path provisioning, and state change management services for a Fibre Channel environment.LUNIn computer storage, a logical unit number (LUN) is simply the number assigned to a logicalunit. A logical unit is a SCSI protocol entity, the only one which may be addressed by theactual input/output (I/O) operations. Each SCSI target provides one or more logical units, anddoes not perform I/O as itself, but only on behalf of a specific logical unit.2010 EMC Proven Professional Knowledge Sharing11

NASNetwork-attached storage (NAS) is file-level computer data storage connected to a computernetwork providing data access to heterogeneous network clients. A NAS unit is essentially aself-contained computer connected to a network, with the sole purpose of supplying filebased data storage services to other devices on the network. The operating system and othersoftware on the NAS unit provide the functionality of data storage, file systems, and access tofiles, as well as the management of these functionalities.Over SubscriptionThe ratio of bandwidth required to bandwidth available. The switch is oversubscribed when allports, associated pair-wise, in any random fashion, cannot sustain full duplex at full line-rate.Port FencingPort fencing is a policy-based feature that allows you to protect your SAN from repeatedoperational or security problems experienced by switch ports. Port fencing allows you to setthreshold limits on the number of specific port events permitted during a given time period. Ifthe port generates more events during the specified time period, the Connectrix Manager(Port fencing feature) blocks the port, disabling transmit and allows you to receive traffic untilyou have time to investigate, solve the problem, and manually unblock the port.Principal SwitchPrincipal switch in a multiswitch fabric; the switch that allocates domain IDs to itself and to allother switches in the fabric. There is always one principal switch in a fabric. If a switch is notconnected to any other switches, it acts as its own principal switch.SANA storage area network (SAN) is an architecture to attach remote computer storage devices(such as disk arrays, tape libraries, and optical jukeboxes) to servers in such a way that thedevices appear locally attached to the operating system. Although SAN cost and complexityis dropping, they are still uncommon outside larger enterprises.VSANAn allocation of switch ports that can span multiple physical switches, forming a virtual fabric.A single physical switch can sometimes host more than one VSAN.World Wide Node Name2010 EMC Proven Professional Knowledge Sharing12

A unique identifier, even on global networks. The WWN is a 64-bit numberXX:XX:XX:XX:XX:XX:XX:XX). The WWN contains an OUI which uniquely determines theequipment manufacturer. OUIs are administered by the Institute of Electronic and ElectricalEngineers (IEEE). The Fibre Channel environment uses two types of WWNs; a World WideNode Name (WWNN) and a World Wide Port Name (WWPN). Typically, the WWPN is usedfor zoning (path provisioning function).ZoneAn information object implemented by the distributed Nameserver(dNS) of a Fibre Channelswitch. A zone contains a set of members which are permitted to discover and communicatewith one another. The members can be identified by a WWPN or port ID. EMC recommendsthe use of WWPNs in zone management. Zoning allows an administrator to group severaldevices by function or by location. All devices connected to a connectivity product, such as aConnectrix switch, may be configured into one or more zones.Zone SetAn information object implemented by the distributed Nameserver(dNS) of a Fibre Channelswitch. A Zone Set contains a set of Zones. A Zone Set is activated against a fabric, and onlyone Zone Set can be active in a fabric.2010 EMC Proven Professional Knowledge Sharing13

A.Designing SAN1.SAN Topology ConsiderationsThe adoption of SANs is driven by a variety of objectives. Some examples are:The need for more efficient use of enterprise storage arraysDecreasing size of backup/restore windowsIncreasing size of data set to be backed upThe need for improved high availability and disaster tolerance solutionsThe need to enhance storage resource managementSAN design can appear to be a challenging task, due to the large number of variablesinvolved in picking an appropriate design strategy. Designing a fabric involves many variablesthat require consideration. With each variable consideration comes a separate designdecision that must be made. Each design decision will help you create a fabric design that isappropriate for your business information model. The following parameters will help inchoosing the right SAN topology according to the requirements.a. AccessibilityAccessibility refers to the ability of your hosts to access the storage that is required to servicetheir applications. Accessibility can be measured by your ability to physically connect andcommunicate with the individual storage arrays, as well as your ability to provide enoughbandwidth resources to meet your full-access performance requirements. A storage array thatis physically accessible, but cannot be accessed within accepted performance limits becauseof oversaturated paths to the device, may be just as useless as an array that cannot bereached physically.An example of a statistical bandwidth network is the telephone system. The telephone systemis not constructed with enough bandwidth resources to allow every subscriber tocommunicate simultaneously. You may have heard "all lines are currently busy; please tryyour call again later." This message indicates that the number of subscribers has saturatedthe bandwidth currently available, so no new connections are possible until resources arefreed.Similar issues can arise in the design and implementation of a fabric. You should alsoconsider the internal design of the switching devices used in your fabric when considering2010 EMC Proven Professional Knowledge Sharing14

accessibility. While switches may be designed for high levels of connectivity and allow manyphysical attachments, their internal designs may cause internal bandwidth congestion.b. AvailabilityAvailability is a measurement of the amount of time that your data can be accessed,compared to the amount of time the data is not accessible because of issues in theenvironment. Lack of availability might be a result of failures in the environment that cause atotal loss of paths to the device, or it might be an event that caused so much bandwidthcongestion that the access performance renders the device virtually unavailable. Availabilityis impacted not only by your choice of components used to build the fabric, but also by yourability to build redundancy into the environment.Another concept that adds to the availability of an environment is sparing, which is theprocess of dedicating resources to remain unused until they are needed to take the place of afailed resource. The following must be considered in your redundancy and sparing plan: How much bandwidth do I need to preserve after a single event occurs? What other applications might be affected when the original storage resources move to a newpath or down to a single path? Do I need to plan for scenarios that include successive failures? Do I want redundancy built into my connectivity components (as seen with director-classswitching devices)? Do I want to build site redundancy and copy data to another site using CLARiiONMirrorView ? Do I want to build redundancy at the host level with a load-balancing and paths failoverapplication (like PowerPath )? How do I rank my business applications so that I can identify lower priority tasks, so theseresources can be used as spares during a failure event? An example of this would be if task onehad failed due to all of its fiber links being damaged and fiber links from task two were used tobring up the resources associated with task one. When the resources were back online, bothtasks would be working at 50 percent efficiency.2010 EMC Proven Professional Knowledge Sharing15

c. Resource ConsolidationResource consolidation includes the concepts of both physical and logical consolidation.Physical consolidation involves the physical movement of resources to a centralized location.Now that these resources are located together, you may be able to more efficiently usefacility resources, such as HVAC (heating, ventilation, and air conditioning), power protection,personnel, and physical security. The trade-off that comes with physical consolidation is theloss of resilience against a site failure. Flexibility is a measure of how rapidly you are able todeploy, shift, and redeploy new storage and host assets in a dynamic fashion withoutinterrupting your currently running environment. An example of flexibility is the ability tosimply connect new storage into the fabric and then zone it to any host in the fabric.d. SecuritySecurity refers to the ability to protect your operations from external and internal maliciousintrusions, as well as the ability to protect accidental or unintentional data access byunauthorized parties. Security can range from restriction of physical access to the servers,storage, and switches by placing them in a locked room, to logical security associated withzoning, volume accessing/ masking.e. SupportabilitySupportability is the measure of how easy it is to effectively identify and troubleshoot issues,as well as to identify and implement a viable repair solution in the environment. The ability totroubleshoot may be enhanced through good fabric designs, purposeful placement of serversand storage on the fabric, and a switch's ability to identify and report issues on the switchitself or in the fabric. Fabric topologies can be designed so that data traffic patterns aredeterministic, traffic bandwidth requirements can be easily associated with individualcomponents, and placement policies can be documented so that troublesome componentscan be identified quickly.2.SAN TopologiesThis section describes the SAN topologies that can be considered for designing a SANaccording to the importance of parameters explained above. This will help us logically decidewhich topology best suits and meets our requirements.2.a Simple Fibre Channel SAN topologiesA simple Fibre Channel SAN consists of less than four directors and switches connected byISLs and which has no more than two hops. A single switch fabric is the simplest of the2010 EMC Proven Professional Knowledge Sharing16

simple Fibre Channel SAN topologies and consists of only a single switch. A simple FibreChannel SAN consists of less than four directors or Fibre Channel Switches.Fibre SwitchStorageServerManagement StationFigure 4. Single Switch TopologyMost Å --------------------Æ yTable 1: Single Switch Subjective RatingThe following best practices are specific for two switch fabrics.ISL subscription best practice — While planning the SAN, keep track of how manyhost and storage pairs utilize the ISLs between domains. As a general best practice,if two switches are connected by ISLs, ensure that there is a minimum of two ISLsbetween them and that there are no more than six initiator and target pairs per ISL.For example, if 14 initiators access a total of 14 targets between two domains, a totalof three ISLs would be necessary. This best practice should not be applied blindlywhen setting up a configuration. Consider the applications that will use the ISLs.2.b Complex Fibre Channel SAN topologies2010 EMC Proven Professional Knowledge Sharing17

2.b.a Full-Mesh fabricA full-mesh fabric is any collection of Fibre Channel switches in which each switchis connected to every other switch in the fabric by one or more ISLs. For best hostand storage accessibility, it is recommended that a full-mesh fabric contain nomore than four switches. A mesh may contain departmental switches, Whendesigningandimplementing a full-mesh fabric, it is recommended that you lay out the storageand servers in a single-tier logical topology design and plan your ISLrequirements based on the assumption that 50% of the traffic on any one switchwill remain local and the other 50% will originate from the remaining remoteswitches.Figure 5. Full-Mesh TopologyBenefitsFull-mesh configurations give you, at most, one-hop access from any server to any storagedevice on the fabric. This means that when you are adding or migrating storage or serverattachments, you have the greatest possibility of placing the server attachment and matchingstorage attachments anywhere in the fabric and achieving the same response time. Meshesalso ensure that you always have multiple local and remote paths to the data even after fabricevents have occurred.LimitationsScaling a full-mesh solution becomes complicated and costly when increasing the number ofswitches and required ISLs to guarantee traffic performance.Most Å ----------------Æ LeastAttribute54321Accessibility2010 EMC Proven Professional Knowledge Sharing18

uritySupportabilityTable 2: Full-Mesh Switch Subjective Rating2.b.b Partial Mesh fabricFigure 6. Partial-Mesh TopologyA partial-mesh fabric is different from a full mesh in that each switch does not have to beconnected to all other switches. However, to be considered a partial mesh, the fabric must bea configuration where splitting it results in each new sub-fabric being a full mesh. For bestfabric response times, both the managed switch (where zoning is activated) and the principalswitch should be at the logical center of the fabric.BenefitsPartial-mesh designs offer extensive access to both local switch storage and single-hopstorage. A partial mesh also extends accessibility and provides many unique paths to thestorage. Increasing accessibility while maintaining the same level of robustness is a designgoal for every topology. Partial meshes also offer a simple progression into a core/edgedesign. If you look at the center of the partial mesh as the core, you can create the newinfrastructure by simply removing some of the ISLs at the outer edges of the fabric.Limitations2010 EMC Proven Professional Knowledge Sharing19

Increasing the fabric size always increases the dependencies within the fabric. This does notcause a problem, but it does increase the complexity of troubleshooting and the impact onunrelated processes during a fabric event.Most Å ----------------Æ yTable 3: Partial-Mesh Switch Subjective Rating2.b Core Edge Fibre Channel SAN topologies1. Within the two-tier design, servers connect to the edge switches, and storage devicesconnect to one or more core switches. This allows the core switch to provide storage servicesto one or more edge switches, thus servicing more servers in the fabric. The interswitch links(ISLs) will have to be designed so that the overall fabric maintains both the fan-out ratio ofservers to storage and the overall end-to-end oversubscription ratio.2. Three-tier: Edge-core-edge designA three-tier design may be ideal in environments where future network growth will result inthe number of storage devices exceeding the number of ports available at the core switch.This type of topology still uses a set of edge switches for server connectivity, but addsanother set of edge switches for storage devices. Both sets of edge switches connect to acore switch via ISLs.2010 EMC Proven Professional Knowledge Sharing20

Figure 7. Core Edge FabricBenefitsThe compound core/edge model maintains a robust, highly efficient traffic model whilereducing the required ISLs, thus increasing the available ports for both storage and hostattachments. It also offers a simple method for the expansion of two or more simplecore/edge fabrics into a single environment. You can easily create a compound core topologyby connecting the core switches from simple core/edge fabrics into a full mesh. Thecompound core/edge topology creates a robust back-end fabric that can extend theopportunities for sharing of both backup and storage resources.LimitationsCore/edge design models produce a physically larger, tiered fabric which could result inslightly longer fabric management propagation times over smaller, more compact designs.Neither compound nor complex core/edge fabrics provide for single-hop access to all storage.Most Å --------------------Æ idationFlexibilityScalability2010 EMC Proven Professional Knowledge Sharing21

SecuritySupportabilityTable 4: Core Edge Subjective RatingBest Practices for Core Edge TopologyLay out the host and storage connectivity such that if a switch fails, not all of aparticular hosts’ storage becomes inaccessible.The use of two separate management networks is more common with balancedfabrics, but it can still be employed when only one fabric is used.ISL subscription best practice — While planning the SAN, keep track of the number ofhost and storage pairs that would be utilizing the ISLs between domains. As ageneral best practice, if two switches are connected by ISLs, ensure that ther

Switch and Zoning Best Practices 28-30 2. IP SAN Best Practices 30-32 3. RAID Group Best Practices 32-34 4. HBA Tuning 34-38 5. Hot Sparing Best Practices 38-39 6. Optimizing Cache 39 7. Vault Drive Best Practices 40 8. Virtual Provisioning Best Practices 40-43 9. Drive

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