The Thoroughly Modern Mainframe

1
The Thoroughly Modern Mainframe

• Dr. Michael Salsburg
• NTSMF Users' Group
• Dec 9, 2002

2
Agenda

• Large Scale WINTEL Servers
• Disruptive technology or trend?
• Scale Up or Scale Out ?
• A Workload-motivated discussion ofSMP and
  CC-NUMA
• PCI-Based I/O
• Consolidation
• Emerging Technologies

3
Server Industry Trends
Source IDC
Intel will dominate server chip market
Windows 2000 will be pervasive server OS
4
The x440 CompetitionGartner Oct 2002
5
A Comparison using Moores Law

• Comparison of CPU Speeds / tpcM for 4x cpu WINTEL
  systems

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TPC-C Top 10
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(No Transcript)
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Scale Up or Scale Out?

• Two of the 3-tiers in current application
  architectures use scale-out for growth
• Increase of Web servers
• Increase of Application Servers
• Database back end cannot be scaled out
• Scale up is needed for large database
  applications
• Scale out has some inherent down sides
• additional administrative/management attention
• Move headroom needed for heavy traffic

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SMP / NUMA Workload Discussion

• As code executes on the processor, memory is
  referenced. This can be broken into three
  regions
• High Locality of Reference
• Memory is immediately re-referenced ( 95)
• Working Set the set of addresses on which the
  software primarily focuses
• Persistent Storage addresses that are stored on
  physical devices

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Scale Out- SMP or NUMA? Workload Interference

• When two processes are running on the same
  system, their memory references will interfere.
• It is preferable to only interfere at the
  persistent storage level
• Interference at higher levels can decrease cache
  efficiency and slow down processing, effectively
  reducing the CPU power

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SMP / NUMA SMP Topology

• A bank of CPUs share a bank of Memory
• Each CPU has a local cache to optimize high
  locality of reference
• A cache miss has uniform latency time to get data
  from memory
• Dirty memory references require fetching the
  updated memory from another CPUs cache
• The CPU can stall waiting for a memory reference

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SMP / NUMA Workload Discussion

• Percentages of references based on TPC-C workload
  profile
• Relative time units show orders of magnitude
  between cache hit and persistent storage

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SMP / NUMA NUMA (Non-Uniform Memory Access)

• Overcome bus congestion and physical fabrication
  limitations found in a single bus architecture
• Two memory latencies near and far
• The NUMA ratio is the ratio of far latency over
  near latency
• Originally 30, now it is around 3

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SMP / NUMA Hybrid (Unisys ES7000)

• Another level of cache is introduced
• Memory accesses can be non-uniform when comparing
  Next Level Cache hits to memory references
• Overcomes the fabrication/congestion problems of
  a single bus architecture

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PCI-Based I/O
Cellular MultiProcessing (CMP) Architecture
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PCI-Based I/O
6.4 GB
6.4 GB
SP2
Scalability Port
533MHz
4
PCI-Express
16X, or 8X_at_5Gb
HyperTransport
PCI-X
3
SP1
GB/sec Max Bus or per direction
266
2
1X 4X 8X
133
1
0.8 GB
PCI
66
2001 earlier
2002
2003
2004
2005
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Enterprise-Level Backup / Restore
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Enterprise-Level Backup / Restore

• Complete recovery of a 2.5 terabyte database
• From tape, the database was recovered in only 88
  minutes with a sustained throughput during
  restore of 2.2 TB/hr.
• From the hardware snapshot, the same database was
  recovered in only 11 minutes.
• Complete backup of a 2.5 terabyte database
• Backup to tape took only 68 minutes with minimal
  impact on online operations and sustained
  throughput of 2.6 TB/hr.

19
Consolidation

• "Our servers were multiplying like rabbits,"
  says Jeff Smith, manager of corporate network
  services at La-Z-Boy Inc., a Monroe, Mich.-based
  residential furniture producer that just
  completed a Windows NT server consolidation
  project. "Our distributed environment was
  becoming more and more difficult to manage."
• Thinning The Server RanksComputerworld Aug 26,
  2002

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Consolidation

• How do you stuff over 130 CPUs worth of workload
  into a 32x CPU system?
• Veeerrrry carefully
• Why are current server farms filled with
  under-utilized servers?
• Web Hosting Sites
• New web servers are installed when Peak CPU
  utilization reaches above 35.
• Speed and reliability are very important to your
  web site. All of our servers are maintained at
  less than 15 CPU utilization. This ensures that
  your web site downloads as fast as possible! 

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ConsolidationResponsive Consolidation

• Which would you prefer an average queue size of
  0.2 on a 1x or a 32x system?

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ConsolidationBenefits

• Simplified Management / Administration
• Higher Utilization (less headroom)
• Less Variability of Service
• Less Overall CPU Overhead
• Less software licenses

23
Emerging CPU Technologies32x INTEL CPU TPC-C
Results
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Itanium IIWhats so great about 64 bits?

• For transaction processing, memory addressing is
  increased and therefore the amount of main memory
  increases
• The top 5 TPC-C results were achieved using 64
  bit computing
• TPC-C is a large database application this is a
  sweet spot for 64 bit commercial computing
• Bigger is DEFINITELY Better!!