Using SAN-Based Raw Disk Mappings and VMware ESX Server to Create Easy and Inexpensive High Availability, Disaster Recovery and Reduced Backup Windows

Dan Weiss, Manager of Network Services

Moore and Van Allen PLLC

AgendaIntroductionCustomer profileBenefits of SANs

Why SANs?Why SANs with ESX Server?

RDMs explainedWhat is an RDM?RDM typesBenefits of using RDMs

Agenda, cont.

Our challengesHigh availability SLAsDR done rightClosing the backup windows

Q & A

Customer ProfileWho Am I?

Graduate of Appalachian State University: 1989Double major: Accounting and Information SystemsCertifications: VCP, MCSE, CNE, CCAFormerly an ERP consultant, programmer, instructor and director of technical servicesVice President of the Charlotte VMware Users GroupCurrently employed at Moore & Van Allen PLLC as manager of network servicesResponsible for networking, infrastructure, DR and securityIn the middle of a 3 year firm-wide DR projectManage a group of 8 technical professionalsEmployed in IT for 16 yearsFirst IT job: Lotus 1-2-3 Macro Developer

Customer ProfileWho Is MVA?

Sophisticated corporate law firm based in Charlotte245 attorneys, 600 employeesAssist local, national and international clients

HistoryFounded in 1950

Locations2 Offices in uptown Charlotte, N.C.Raleigh, N.C. and Charleston, S.C. Offices

Contacthttp://www.mvalaw.comdanweiss@mvalaw.com

Customer ProfileMVA’s IT Snapshot

1.5Tb of active messaging data (not including archive)2Tb of active documents (not including archive)+-35Tb of SAN based storage (98% VMware)174 Servers3 offices10Mb Extended NativeLAN links with T1 Backup LinksDual 6Mb Ethernet Internet Service running BGP

Customer ProfileMVA’s IT Snapshot, cont.

2 Offices in uptown Charlotte connected via dark, single mode fiberRaleigh, NC, and Charleston, SC, officesEMC Clariion SANs using asynchronous mirroring13 VMware ESX Servers – mostly quad processorCost of downtime: $30,000 per hour

Why SANs?Why complicate your data center with a SAN?

Pay as you growCentralize storage managementLayered applications

SnapshotsClonesMirroring

Prevent inefficiency: captive storageNon-disruptive, on-line LUN expansion

Why SANs?Why complicate your data center with a SAN? (cont.)

Transfer rates up to 3x SCSI ArraysWrite-back cacheRedundant data paths from server to storageContinuous data protection/correctionNew features such as iSCSI, NAS on SAN, ILM, etc.LAN-free backups

Why SANs With ESX Server?Share physical HBAsShare FC switch portsPay as you grow-great for VMFSBoot from SANMultipathing within ESX ServerVirtual to virtual clusteringPhysical to virtual clusteringRDMs

What Is an RDM?An RDM:

Is a way for virtual machines to directly access LUNs on a SANIs a way to merge VMFS manageability with the power of SANUses symbolic links to proxy access from a mapping file to a SAN LUNSystem/boot drive of a virtual machine is a traditional .vmdkfile on an VMFS partition, additional (non-bootable), would be created as an RDM

Two Different Kinds of RDMsRDM compatibility mode:

Virtual Mode-Allows mapping to a SAN LUNCan still use Vmotion and REDO logsOK for N + 1 Clustering

Physical Mode-Direct SCSI pass-thruNo Vmotion and REDO logsCan use SAN Layered AppsRDMs maintain pathing on SAN no matter which ESX Server they run from or which VMFS partition they are on

Physical vs. Virtual RDMs

How Do I Benefit by Using RDMs?RDM benefits:

Ability to use SAN layered applications such as snaps, clones, and mirroring (where supported by storage vendors)Ability to use Storage Resource Management (SRM) softwareRecommended way to do virtual to virtual and virtual to physical clusteringPerformance improvement???Physical to virtual and virtual to physical

High AvailabilityWe need critical systems to failover within 15 minutesNon-critical systems should be available within a business dayTerrabytes of data on physical servers

Difficult to quickly move/migrateNo easy way to protect data

Tried host-based replicationUsed VMware for N + 1 targetsToo much host overhead for busy and critical servers

Needed SAN capabilities but also needed VMware’sserver virtualization and ease of managementSAN and ESX Server was the logical next step

Disaster RecoveryRequired mirroring of data to another SANNeeded Snaps and BCVs (clones) for roll-backsWanted quick recovery without the wait of a long restoreServer sprawl and rapid deployment were requirementsSAN and ESX Server was the logical combinationE-mail (Exchange) and document management (Hummingbird) are top applications

Closing the Backup Window36 hour backup windows!Creeping into the workday from the night beforeBackup to disk was better, but not by muchMan-hours spent managing backup jobsNeeded LAN-free backups and restoresSnaps and BCVs are backed up in most cases

The virtual machine is never tied up in a backup jobExchange and SQL benefit the most

ResultsAll critical data (physical servers or virtual servers) is SAN-basedCan easily P to V or V to P as necessaryESX Servers share a common VMFS partition

Non-critical virtual machines and RDMsEasy to migrate traditional virtual machinesAny ESX Server can host an RDM-based virtual machine without remapping

Snaps and BCVs each dayCost savings of $184,000 in 2004 and estimated to be $250,000 in 2005All critical data is mirrored to DR site via SAN replication