1. Proving Hardware Bottlenecks &
Architecting For Performance
Matt Henderson: Principal Solutions Architect

2. Agenda
I/O and databases
What to look for
Monitoring tools & techniques
What could be…

3. RAM versus Storage SQL Buffer PLE: Page Life Expectancy Working Set
MRU – LRU chain
Temp tables & 2nd reads
PLE: Page Life Expectancy
How long a page lives in the chain before being cycled out
MSFT recommends over 300 (5 minutes)
Working Set
How much data do you want/NEED in RAM?
Database size isn’t relevant
What’s being worked on now, what will be in the near future?
Workload profile
What data are the users hitting?
Is there any way to predict the future data page hits?

4. CPU Schedulers & Times Slices
One SQL scheduler per logical core
SQL scheduler time-slices between users

5. Waits & Queues Running Waiting Runnable Currently executing process
Waiting for a resource (IO, network, locks, latches, etc)
Runnable
Resource ready, waiting to get on CPU

6. Wait Statistics: Guided Tuning
Waits: What is keeping the SQL engine from continuing?
Application (SQL)
Hardware
Architecture
Tuning
sys.dm_os_wait_stats
WaitType
Wait_S
Resource_S
Signal_S
WaitCount
Percentage
AvgWait_S
AvgRes_S
AvgSig_S
BROKER_RECEIVE_WAITFOR
661.36 4
44.6
LCK_M_IS
139.46
139.35
0.11
489
9.4
0.2852
0.285
0.0002
LCK_M_X
96.86
96.54
0.32
373
6.53
0.2597
0.2588
0.0009
LCK_M_U
83.93
83.91
0.02 32
5.66
2.6227
2.6221
0.0006
PAGEIOLATCH_SH
83.92
83.84
0.08
9835
0.0085
LCK_M_S
82.44
82.1
0.33
419
5.56
0.1967
0.1959
0.0008
ASYNC_NETWORK_IO
54.4
53.61
0.79
33146
3.67
0.0016
ASYNC_IO_COMPLETION
43.1 37
2.91
1.1649
BACKUPIO
42.22
42.19
0.03
12607
2.85
0.0033
BACKUPBUFFER
36.64
36.48
0.15
2175
2.47
0.0168
0.0001
LCK_M_IX
30.88
30.85
130
2.08
0.2376
0.2373
0.0003
IO_COMPLETION
28.12
28.11
0.01
2611
1.9
0.0108
CXPACKET
23.27
21.6
1.67
3542
1.57
0.0066
0.0061
0.0005
PREEMPTIVE_OS_CREATEFILE
18.84
247
1.27
0.0763

7. CPU Utilization & Storage
CPU’s are faster than hard drives
Adding cores does not correct issue
8 10% = 1 80%
40% utilization = 60% over paying

8. Reduce I/O Wait: Maximize CPU Utilization
< 0.2ms
Maximize CPU utilization

9. Accelerate & Consolidate
Same CPU’s
Same work
Less time
Consolidate
Fewer cores = few licenses

10. I/O Patterns: MAXDOP & OLTP
BI: MAXDOP
Dozens of parallel workers
Large batch reads (256k)
Sequential per worker
Bandwidth limited
Latency spikes effect parallel completion
Flushes buffer = low PLE
OLTP
8k page reads, 4k tran log writes
70r/30w common I/O mix
8k read latency effects performance more than 4k log write
Random I/O pattern
Clustered Index matters
PKs, FKs, multi-table & multi-step xacts

11. SQL & Windows Performance Monitoring
PerfMon (Performance Monitor)
Live & recorded stats
Good for system, not SQL
typeperf
Command line tool; live stats
typeperf "\LogicalDisk(*)\Avg. Disk sec/Read"
Resource Monitor
Live file stats, not recorded
Good for processes and files
SQL DMV’s
File: sys.dm_io_virtual_file_stats
Waits: sys.dm_os_wait_stats
I/O: sys.dm_io_pending_io_requests
Objects: sys.dm_os_waiting_tasks
Queries: sys.dm_exec_query_stats
Indexes: sys.dm_db_index_usage_stats

12. Architecting for I/O
Rule of Many: At every layer utilize many of each component to reduce bottlenecks
Virtual disks: 2-4x the existing LUNs
Database files: many per LUN, copy files in parallel
TempDB files: 1 per physical core
MPIO paths: minimum 4 paths per port
MPIO policy: Least Queue Depth
Physical ports: 825MB/s per FC16 port
LUNs: 2GB/s per LUN
Parallelization: Use many objects and many processes to increase parallel workloads
Spread transactions over pages
Use a switch (path multiplier)
Increase MAXDOP (and test)
I/O Latency: Is Sacred. Don’t add anything to the I/O path that doesn’t need to be there
LVM (Logical Volume Manager)
Virtualization
Compression
De-dup

15. Data Warehouse Fast Track: CPU Efficiency & Performance
Broadwell, 2 CPU, 12-core, 3.0GHz, 8 x 16Gb FC
Vendor
Rating
CPU Cores
Efficiency
XtremeIO
20TB 32
0.63
Leveovo (NVMe DAS)
22TB 40
0.55
Pure
23TB
0.58
Lenovo (TMS)
60TB 56
1.07
Vexata
70TB 48
1.46
AVG throughput
Over 8 GB/s
PEAK throughput
Over 13 GB/s

16. DEMO