3 Agenda Why should you care about Flash based storage disks? Types of Flash based storage disksDell Flash based storage solutionsCase studies – performance analysisQ&A
4 Why should you care about Flash based storage disks?
5 Why should you care about flash based storage drives? HDDs are performance limited by the spinning speed of the disk (15K rpm) and its mechanical head movementCompared to HDDs flash based storage or Solid State Drives (SSDs)Have no moving partsExtremely fast, low-latency, and high IOPSSingle SSD can replace many HDDsConsolidate rack spaceSave on power and coolingFASTERSLOWERFlash SSD Technologies
7 Types of flash based storage disks or SSDs FASTERSLOWERFlash SSD TechnologiesSAS/SATA based SSDsUse the same SAS/SATA based interface as HDDsAccessed by the system through OS driver stackPerformance better than HDDs but still limited by OS driver stackPCIe based SSDsDirectly connected to PCIe busDirectly connected to CPU and system memory through PCIe busFaster than HDDs and SAS/SATA based SSDsTwo typesSingle-level cell (MLC) NANDBest suited for performance intensive applicationsSmaller capacityMulti-level cell (SLC) NANDSuited for applications having high capacity requirementsLower cost alternative to SLCs
9 Dell Flash based storage solutions Server-side PCIe SSD based solutionsDatabase directly on Dell PowerEdge Express Flash PCIe SSDsDatabase cached on Dell PowerEdge Express Flash PCIe SSDs using Fluid Cache for DASStorage-side PCIe SSD based solutionsDell Compellent All-Flash arraySAS/SATAPCIe-SSD
10 Case studies –Dell Flash based Storage Solutions Performance analysis
11 Case Study #1 Oracle OLTP Database directly on Dell PowerEdge Express Flash PCIe SSDs
12 Introduction to Express Flash PCIe SSD Directly connected to PCIe busUp to four PCIe SSDs per server2.5 inch plugged into a device bayCapacity: 175GB/350GBHot Swappable: add or remove a device without halting or rebooting the systemThe Dell PowerEdge Express Flash PCIe SSD is built with SLC NAND flash andcan be used as an internal storage of Dell PowerEdge servers. This not onlyremoves the performance bottleneck posted by the mechanical parts ofconventional HDDs, also improves the storage IO performance by eliminatingthe latency and performance bottleneck between the server and the externalstorage. For example, a single Express Flash PCIe SSD drive response time canresult in up to 26 ms, up to 1/4th lower than 4 SAS SSD drives and up to1/10th the latency of 16 traditional HDDs. This makes PCIe SSDs the idealstorage for the applications that require low latency and high IOP (IO PerSecond) operation. Figure 1 shows that the Dell 12 Generation PowerEdgeserver R720 can have up to 4 high performance internal PCIe SSDs drives inadditional to the regular SAS or SATA drives which are usually used for OSand local file systems. The four PCE-e SSDs drives fit into driver carries andare front accessible and can be used for improving the database performance.Enterprise-grade SLC NAND and sophisticatedNAND-management algorithms deliver up to12.5 and 25 petabytes of drive life (175GB/350GBcapacity, respectively). Also, since NAND SSDshave a finite number of program and erasecycles, Dell warrants the Express Flash PCIe SSDto a maximum amount of data written to theSSD in total bytes written. The SSD monitorsthese cycles, and Dell software managementapplications notify you when the warranty limitsare reached.
13 Use Cases of PCIe SSDs for Oracle Database Use PCIe SSDs stores the entire database schema.PCIe SSDs stores portions of a database schemafour PCIe SSDs combining withMD3220 external storage with 24HDDsPCIe SSD used as Oracle Smart flash cache in a 11g R2 RAC Databasetwo PCIe SSDs combining with
14 Performance Testing Results Use PCIe SSDs stores the entire database schema:comparison of two configurations:Baseline: the entire database schema stored in Hard Disk Drives (HDDs)Compared group: the entire database schema stored in PCIe SSDsTPS Comparison: 569% increaseResponse time (MS) Comparison:250% increase of # of users for 1 second time99 times reduce of query response timefor 600 users
15 Performance Testing Results User case 2: PCIe stores partial database:Config1 : all the database objects stored in HDDs. (Base Line)Config2: all indexes stored in PCI-e SSD Drives ,Config3: all indexes plus one most active table stored in PCI-e SSDsConfig4: all indexes plus four active tables stored in PCI-e SSDResponse time Comparisons:TPS Comparisons: %-200% increase of # of users in 1 sec mark14%-310% TPS Increases times decrease of response time for 800users
16 Performance Testing Results Use PCIe as the smart flash cache for RAC--- an extension of database buffer cacheConfigure PCEI SSD as Oracle Smart cache:Set udev rule in /etc/udev/rules.dKERNEL=="rssda1",OWNER="oracle", GROUP="dba", MODE="0775"
17 Performance Testing Results SELECT name, value FROM v$sysstatWHERE name IN ('physical read flash cache hits', 'physical reads', 'consistent gets', 'db block gets', 'flash cache inserts');NAME VALUEdb block getsconsistent getsphysical readsphysical read flash cache hitsflash cache inserts44.8% increase of TPS (Transactions Per Second)
18 Performance Testing Results 5.8 times decrease of Query Average Response Time
19 Performance Testing Results Observed different database wait patterns
20 Performance Testing Results Free buffer wait eventProcess A: Fast data read from smart flash cacheProcess B: Slow process to free a slot in memory due to the slowwriting a dirty block to diskFast process A has to wait for slow process B Free buffer wait
21 Oracle Deployments: Challenges Business Challenges:Structured Data Growth at CAGR > 50%Flat or declining IT budgetsDo more with lessSupport aggressive Goto market requirementsTechnical Challenges:Increase performance and availabilityIncrease AutomationReduce Management ComplexityIncrease online data accessibility
22 Case Study #2 Oracle OLTP Database on Dell Compellent All-Flash Storage Array
23 Solving Database challenges Common Approaches:Add more processing/ memoryAdd more storageAdd Server FlashHigh touch database tuning and managementLimitations:Limited effectivenessStorage overprovisioning not sustainablePoint fix/Capacity Constrained
24 Better Solution: Automated Tiered Storage Benefits of Automated Tiered Solution:Increase performance without increasing costScale performance/capacity independentlyRight data in the right place at the right time – at the right costAutomation reduces management overheadIncrease amount of data that is onlineLeverage existing investments
25 New Compellent All Flash Array Solution Flash Tiering Economics:Improve cost per GB and cost per I/OReduce HW requirementsReduce SW LicensingReduce maintenance/support costsReduce environmental cost factorsIncrease SSD CapacityReduce SSD costs80%5X75% Lower CostThan most All-Flash solutions>300K IOPS>100,000 IOPS and sub-millisecond latency running OLTP workload
26 Read Intensive Enterprise SAS SSD Write-Intensive Enterprise SAS SSD SSD TieringHow it works:Flash Optimized TieringWrite Intensive Tier for Reads/WritesRead Intensive Tier for Read Only DataOn Demand data progressionFlash Optimized Storage ProfileEnhanced Flash Wear monitoringCapacity addition through NL-SAS$$$RAID 10$$RAID 5$RAID 6Read Intensive Enterprise SAS SSD(1.6TB MLC)HDD(15K, 10K, 7.2K)Write-Intensive Enterprise SAS SSD(400GB SLC)Tier 1Tier 2Tier 31. Dell case study: 7-Eleven; 2, Salesforce.com
27 Performance Test Environment Test Hardware:2 X M820 Blade ServersBlade IO modules:A: M GbE SwitchB: Force 10 10GbE SwitchC: M GB FC SwitchStorage : 2 X SC8000 Compellent Controllers4 X SC220 enclosures:72 X 15k SAS disks6 Write Intensive (SLC)SSDs6 Read Intensive (MLC) SSDsTest Software:Oracle Linux 6.4 UEK kernelOracle Database EnterpriseEditionOrionDell Quest Benchmark Factory100%86%
33 Case Study #3 Oracle OLTP Database Cached on Dell PowerEdge Express Flash PCIeSSDs using Fluid Cache for DAS
34 What is Fluid Cache for DAS? Server-based caching technologyLeverages Dell’s hot pluggable PowerEdge Express Flash PCIe SSDsTransparent to the ApplicationReduces latency & accelerates response times for any Linux-based application needing improved random IO reads and writes (i.e. Oracle OLTP) or sequential readsConsists of software, PowerEdge w/ Express Flash and optional PowerVaultOSOracle Linux 6.2 (RedHat Compatible Kernel)PlatformsR620, R720, R820, T620RAID ControllerDell PERC H710P, H710, H810
35 Fluid Cache for DAS Differentiators Write-back cache accelerates data writes as well as readsPools up to 4 Express Flash PCIe SSDs in a serverProtects write cache data with efficient block replication technologiesCombines performance enhancements with data integrityCache stays warm on rebootSAS/SATAPCIe-SSD
36 PowerVault JBOD Storage PowerVault JBOD Storage How Fluid Cache works: Enables High Speed Flash Performance for Direct Attached StorageShared Read/Write Cache PoolServer>50x IOPSFluid Cache for DASOracle DatabasePCIe SSDs1X IOPS1x IOPSShares PCIe Flash Cache Pool for VDs across up to 3 RAID Controllers (only 2 used here)RAID cont.InternalStorageRAID cont.RAID cont.ExternalPowerVault JBOD StorageExternalPowerVault JBOD StorageDell (Server + Storage+ Flash) + Fluid Cache Application Acceleration
37 Fluid Cache for DAS: Oracle OLTP Database reference architecture PowerEdge R720Database & OSOracle Single Node 11gR2 Enterprise or Std. Edition DB SWOracle Linux 6.2 (RedHat Compatible Kernel)PowerVault MD1220H810 connected to MD1220s in balanced modeMD1220s connected in a daisy chain8 x R10 Data Volumes, 4 x R5 FRA* Volumes, 12 Global Hot Spares* FRA – Flash Recovery Area (contains Archive Logs, Backups, etc.)
38 TPC-C Performance: Transactions per second (TPS)
39 TPC-C Performance : Average Response Time (ART)
41 Fluid Cache for DAS Resources Dell Express Flash PCIe SSDs –Fluid Cache for DAS user’s guide - ftp://ftp.dell.com/Manuals/all- products/esuprt_electronics/esuprt_software/esuprt_cache_soluti ons/dell-fluidcache-das_User's%20Guide_en-us.pdfOracle OLTP Fluid Cache for DAS reference architecture white paper – ftp://ftp.dell.com/Manuals/all- products/esuprt_electronics/esuprt_software/esuprt_cache_soluti ons/dell-fluidcache-das_White%20Papers90_en-us.pdf
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