Storage Area Network at Sheffield Hallam University

The Storage Area Network at Sheffield Hallam UniversityNik Sellars Servers and Storage Service ManagerInformation Systems & Technology (IS&T)1The SAN at SHUOverviewFirst SAN implemented in 2000Two Data Centres Fibre Channel NetworkTwo FabricsComponents of the SAN at SHUFibre Channel SwitchesApplication ServersTape LibrariesDisk Storage ArraysNexsanDell Compellent Fibre Channel Switches10 x Brocade 6510 & 500048 / 32 ports 2, 4, 8 and 16Gb/s

Application ServersOperating SystemsVMWare ESX (32, 750 virtual)Windows (24)Solaris (10)Linux (6)Netware (4)Processor ArchitecturesIntel / AMDSUN SparcHost Bus Adaptors (HBAs)EmulexQlogicBrocade

Tape Libraries2 x Quantum Scalar i6000Four LTO 5 Tape Drives1.5 TB per Tape (3TB compressed) Robot Arm744 Tape SlotsControlled by IBM Tivoli Storage Manager

Nexsan Disk Storage Arrays9 x Nexsan SATABeast Some High Availability FeaturesFixed PerformanceSAS or SATA DisksNo Advanced FeaturesHigh DensityCheap

Dell Compellent Disk Storage Arrays4 x Compellent Storage CentersHigh Availability (no single point of failure)RAID, Hot Spare, Multi-pathSSD, FC, SATA and SAS DisksScalable PerformanceFeature Rich Large Initial Investment

Dell Compellent Storage CenterWe have four Compellent Storage Centers, one located at City Campus, the other at Hallamshire Business Park

Components of the Dell CompellentsControllersDisk enclosures (SBOD, SATA, SAS) DisksSoftwareControllersEach Storage Center has dual clustered SC-040 Dell Compellent storage controllers2.53 Ghz Quad Core, 6GB RAM, 6 x PCI-E slots

ControllersConnectivity3 x 4 Port, 4 Gbps FC (Qlogic) per Controller6 Back End, 6 Front End (Including 2 Mirror)1 x 4 Port SAS (LSI) per ControllerEach port, 4 lanes, 6 Gbps per lane, 96 Gbps total1 x 2 Port, 1 Gbps iSCSI Cards per Controller1 x IP Interconnect1 x IP Management Port

Disk Enclosures7 x SBOD Disk Enclosures, fibre connect2 x SATA Disk Enclosures, fibre connect16 x SAS Disk Enclosures, SAS connect

DisksTier 1, SSD, 146GB, 2 active (+1 hot spare)2500 IOPS per disk15 per GBTier 2, FC / SAS, 15k, 300GB / 600GB, 174 active (+8 hot spare)180 IOPS per disk1.30 per GBTier 3, SATA / SAS, 7.2k, 2TB, 140 active (+10 hot spare)70 IOPS per disk0.25 per GB

SoftwareStorage Center System Manager (SCOS)Runs on the controllers (Free BSD)Management interface for Storage CentersCurrent version 6.3.10 (64-bit)Java based GUI

Features of the Dell Compellent Storage CenterStorage VirtualisationThin ProvisioningAutomated Tiered StorageSnapshotsRemote ReplicationLive Volume

Much of this functionality builds on the Dell's Dynamic Block Architecture. This feature is unique to Dell.

Traditional Storage ArchitecturePhysical disks - Different Types15K SAS / FC

7K SAS / SATATraditional Storage ArchitectureDivided into RAID Groups15K SAS / FC

7K SAS / SATARAID Group1 - RAID 10, 12 disks 15KRAID Group2 - RAID 10, 4 disks 7KRAID Group3 - RAID 5, 9 disks 7KRAID Group4 - RAID 5, 5 disks 15KRAID Group5 - RAID 10, 12 disks 15KRAID Group6 - RAID 5, 9 disks 7KRAID Group7 - RAID 5, 9 disks 7KRAID Group Divided into LUNsData written in blocks

Traditional Storage ArchitectureLUN101 - 500GBLUN102 - 60GBLUN103 - 250GBLUN104 - 100GBLUN105 - 100GB

Traditional Storage ArchitectureLimitationsDisks allocated to RAID GroupsDifficult to change laterSpace allocated to LUNs when they are createdCan't reduce and reallocate later Difficult to expand size of LUN or RAID grouprestriping of dataFree space can get fragmentedFree storage inevitably ends up in the wrong place

Traditional Storage ArchitectureMore LimitationsRAID set tied to a single disk typeLUNs tied to a single RAID groupTherefore LUNs tied to a single disk and RAID type

Dynamic Block Architecture enables functionalityBuilt-in at the block levelNo performance or capacity impact

Metadata for each block includesCreation, Access, and Modification timeFrequency of accessType and Tier of disk driveRAID levelCorresponding volume (LUN)Data type

Dynamic Block ArchitectureMetadataDiskData blocks22Dynamic Block ArchitectureDisks are not allocated to RAID GroupsLUNs are not created within RAID GroupsSpace is not allocated to LUNs when they are created

Disks are grouped into tiers by typeTier 1 SSDTier 2 15K, FC / SASTier 3 7K, SATA / SASAll disks are virtualised (pooled)LUNs (or Volumes) are created from the poolAll Volumes are thin provisionedAll Volumes are assigned a Storage Profile

Dynamic Block ArchitectureStorage ProfilesDefine which tiers of storage a Volume can use. A single volume can be spread across multiple tiers.Define which RAID types a Volume can use. A single volume can be spread across multiple RAID types.Within tiers, frequently accessed data is placed on the outer tracks of the disk for increased performance.Data progression runs every 24 hours and moves blocks based on metadata.

Automated Tiered StorageDefault Volumes on the SHU Storage Centers. All data is written to Tier 2, RAID 10Within 24 hours this is re-striped to Tier 2, RAID 5 (5 disks)Data not read in 12 days is moved to tier 3, RAID 6 (10 disks)Data read twice in 4 days progresses back up to Tier 2, RAID 5 (5 disks)SnapshotsFull CopyConsumes additional storage capacityTakes long time to createCopy on First WritePerformance overheadDifficult to recover to earlier point in timeRedirect on WriteNo performance overheadEasy to recover to earlier point in time27Snapshots (Replays)GUI scheduling interfacePolicy Driven Manual and Scripted replay creation Space efficient, time based replaysA Replay can be mapped to any serverReplays are read and writeCan recover without full clone or rollbackCompellent Solution11:4512:0012:1512:30Remote ReplicationAll snapshots (replays) are asynchronously replicated from City to HBPActive replay is used to replicate changes between replays

SummaryWhat we have coveredBackground and Architecture of the SAN at SHUMajor Components of the SAN at SHUCompellent Storage CenterQuestions?Demo