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EMC Performance. John Popplewell ICL Distinguished Engineer john.popplewell@icl.com . Disclaimer. EMC have two product ranges Symmetrix Clariion This presentation is primarily about Symmetrix.
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EMC Performance John Popplewell ICL Distinguished Engineer john.popplewell@icl.com
Disclaimer • EMC have two product ranges • Symmetrix • Clariion • This presentation is primarily about Symmetrix • An EMC system is an intelligent piece of software controlling a cache, controlling industry standard discs. • Two aspects to its performance • FC or Trimetra Controller Cabinet performance • EMC cache performance • Outside the scope of this presentation
EMC Overview • EMC models • Symmetrix 32 Gb cache • Clariion 0.5 Gb cache • ICL processor models • DL & Nova – direct FC connect • SY - connect via ICL peripheral controller (SDS3) • Clariion => DL & Nova • Symmetrix => SY & Nova & DL
EMC StorageWhat does it provide? • Disc Storage • Guaranteed availability • Symmetrix Raid 1 & Raid S* • Clariion [Nova & DL] Raid 1/0 – mirrored and striped (64 kb) • Good performance • Multi platform support within one box • Common storage • Flexibility - investment protection • Fast data copying • Background volume copies (BCV’s) • Offline archiving • Business Continuity • Remote mirrors (SRDF-Symmetrix Remote Data Facility) [* Raid S not supported on VME]
EMC Symmetrix Connection to VME NOVA & DL VME Connection VME System Node Node Node Node IOP IOP IOP IOP Switch Switch SRDF links (dark Fibre channel fibre), external converters needed to use E3/ATM links etc Channel Directors Remote Link ( CDs ) for VME CD CD CD CD Channel Directors co nnection (Escon) (Escon (RLD) (RLD) (paired for resilience) ( RLDs ), for SRDF (paired for resilience) Groups of VME Log Vol Logical Volumes BCV Copy (mirrored for resilience) & their (optional) BCVs Phone Home Symmetrix
EMC Configurations Any SDS3/EMC configuration must be addressed from the three points of: • Capacity • Connectivity • Performance
SDS3/EMC Capacity • Work out the amount of filestore require to replace the existing discs • EMC physical volume • 18, 36 or 73 Gb • Nova Configured as 4 or 9Gb logical volumes • SY Configured as 9Gb logical volumes • DL Configured as 4Gb logical volumes • Each VME 9 Gb logical volume contains ~ 8 Gb • VME is a variable block architecture, therefore 2048 bytes requires 5 * 512 byte fixed blocks • Red tape, headers trailers etc. • Capacity is block size dependant
EMC Capacity 0 2048 ` 10k
EMC view Channel directors 4 SCSI per channeldirector BUS Cache Disc directors x discs per bus (depends on Symmetrix type)4 buses per disc director EMC Connectivity
VME SY - EMC Connectivity • EMC Symmetrix are connected to VME-SY via a Trimetra Controller cabinet • Each TCC contains 4 controllers • Controllers are organised in pairs • A controller pair supports 32 9 Gb logical volumes • The EMC systems are configured with varying numbers of channel directors. • Each channel director supports 4 SCSI interfaces. • Each controller pair requires two SCSI connections in different channel directors.
VME SY - EMC Connectivity • Use fully populated Trimetra Controller cabinets • No resilience benefit in configuring two cabinets with 1 controller pair, rather than one cabinet with two controller pairsunless the cabinets are in different rooms • Smartfibre recommendations • No more than 4 controllers per Smartfibre • Same controller connectivity rules as existing VME controllers, i.e. a SDS controller can be attached to a single or multi-node system, or a partitioned system • An EMC channel director can connect to more than 1 VME system.
SDS/EMC Performance • SDS Controller performance Type IOP’s Controllers / controller cabinet SDS Mk3 ~600 4 Depends a lot on the blocksize(above for reasonable response times, i.e. less than 30 msec response times for 2 Kb xfer) • Safe figure is 250 IO’s second per controller • 4 Controllers per Cabinet • 64 spindles per cabinet • Therefore, a safe figure is ~15 IO’s per second per spindle
SDS3/EMC Performance • CAFS • 4 CAFS controllers per Trimetra Controller Cabinet • Searching speed is a function of hit rate, record size etc. • Rates in Mb / sec hit rate SDS3 SA300T & SA300 • Min 20% 2.56 3.4 • Ave 6.1 6.9 • Max 0% 6.6 7.5
EMC Performance Disc Gb Disc Index SA100 1.43 2.06 SA200 2.88 1.77 SA300 (4.3) 4.3 1.99 SA300 (9) 9.0 1.95 SA150 2.15 2.25 SA300T(9) 9.0 1.86 SA300T(4) 4.0 2.08 LY Disc (9) 9.0 1.63 LY Disc (4) 4.0 1.80 EMC (SDS3) 32 (36) 4.68 assuming 80 % cache hits EMC (SDS3) 8 (18) 4.97 assuming 80 % cache hits GI20 2.88 1.54 GI30(4) 4.0 1.88 GI30(9) 9.0 1.70 ESS 0.65 4.34 FDS20G 2.3 1.14 FDS5000 1.27 1.00 FDS2500 0.62 1.05 FDS760 0.76 1.01 FDS300 0.31 0.91 • Mixture of serial, random and different block sizes
EMC Performance • Benchmark results • Runtime • Heavy IO ~30% of original time • Typically ~70% of original time • OCP dominant ~100% of original time • BCV Establishment • Depends on number of drives etc. • Establish (measured)32 * 9Gb volumes ~ 75 mins • Establishment done in parallel • Therefore done 36 Gb in 75 mins • rate is 8 Mb/sec (Ultrafast SCSI nominal 40 Mb/sec) • Disc rate ~10 => 15 Mb/sec • Split BCV from 1st system and introduce into 2nd system ~ 5 mins
EMC Q&A’s • Q1 Mainframe attach • “Can a SDS controller attach to two VME Systems” • While an EMC system can attach to more than one system, each SDS controller can attach to a single or multinode system - or a partitioned multinode system
EMC Q&A’s • Q2 RAID • Is RAID1 (mirroring) standard? • Yes • Is RAID S supported • No
EMC Q&A’s • Q3 VME / IDMS Duplexing or SRDF? • Discuss ! • IDMS or VME • 1 read and two writes through SDS3 controller • With single EMC frame, twice as much data in EMC cache • EMCMirroring • 1 read and 1 write through the SDS3 controller • Propose • VME Systems distributed < 2Km • VME or IDMS plexing rather than EMC SRDF • Each site will have processors, Smartlans, Internodes etc • With EMC mirroring, 4 copies of data • VME systems distributed > 2 Km • Use EMC SRDF • Need alternative system at remote end • Min of 3 copies of data, probably 4
EMC Q&A’s • Q4 CAFS • “Does CAFS work and what rate can we expect” • Yes, CAFS works, low hit rate comparisons Controller EMC Rate SA300 7.5 Mb/sec SDS2 4.7 Mb/sec SDS3 6.6 Mb/sec
EMC Q&A’s • Q5 Facilities • SRDF (non sys discs) • BCV’s • IPL • SRDF & Sys discs
EMC Q&A’s • Q6 VME Release • “What release of VME is required?” • OVME2 onwards • EMC is SY only
EMC Q&A’s • Q7 BCV issues • Outside the control of VME • BCV’s of a total system are OK • Catalogue and FLF contain information • BCV’s of part of a system (application) are possibly fraught with danger -think • Careful filestore design
EMC Q&A’s • Q8 Hot spares • “are these included in the limit of 96 or 384 discs physical discs?” • Yes and No, • they are invisible to VME • however, the customer has to purchase the hot spares, so beware if fully populating boxes • why buy them -- speedy availability
EMC Summary • Disc Storage • Guaranteed availability (Raid 1 & Raid S***) • Good performance • Multi platform support within one box • Common storage • Flexibility - investment protection • Fast data copying • Background volume copies (BCV’s) • Offline archiving • Business Continuity • Remote mirrors (SRDF-Symmetrix Remote Data Facility) [**** Raid S not available on VME]