Exchange Storage Sizing and Hardware Exposed Jim McBee

Who is Jim McBee!!?? Consultant, Writer, MCSE, MVP and MCT – Honolulu, Hawaii Principal clients (Dell, Microsoft, SAIC, Servco Pacific) Author – Exchange 2003 Advanced Administration (Sybex) Contributor – Exchange and Outlook Administrator Blog ● ●

Agenda The sizing quandary User usage profiles Microsoft’s hardware recommendations Network sizing RAM sizing CPU sizing Disk sizing Did you get it right?

The sizing quandary

Typical solution Throw hardware at the solution… Sometimes you get it right… ● and sometimes you don’t… Often disk capacity is still undersized

Usage profiles

Messaging user types TypeMessages sent/received Mailbox size Light5 sent 20 received 50MB Average10 sent 40 received 100MB Heavy20 sent 80 received 200MB Large30 sent 120 received 500MB

Active Directory

Sizing domain controllers Use Windows 2003 SP1 if possible Windows 2003 domain and forest functional level Use 4:1 ratio ● For each 4 Exchange CPUs/cores use 1 DC/GC core ● This ratio assumes dedicated Exchange DCs Redundant DNS servers and domain controllers Larger Active Directories… ● Put transaction logs and databases on different spindles ● If NTDS.DIT database exceeds about 1GB, use Windows the /3GB /USERVA=3030 switches ● If the NTDS.DIT database exceeds about 2.5GB, use Windows 2003 x64 or Windows 2008 x64

Problem indicators MSExchangeDSAccess Process – E2K3 MSExchange ADAccess Domain Controllers ● LDAP Read Time ● LDAP Search Time Should be below 50 milliseconds on average Should never exceed 100 milliseconds

Network sizing

Network connections 100Mbps / Full Duplex Switched backbone is best Ensure that network adapter is inserted in to network at maximum speed possible ● May require manual configuration on server and switch Use separate 1GB Ethernet connections for iSCSI

Key indicator you may have network problems Performance monitor: ● MSExchangeIS / RPC Averaged Latency Should be below 50 milliseconds May indicate hardware problems, but network is often the culprit ● Network Interface / Bytes Total/sec Watch for this counter to approach maximum network bandwidth

CPU sizing

Microsoft’s recommendation Server roleMinimumRecommendedMaximum Mailbox1 CPU core4 CPU cores8 CPU cores Client Access1 CPU core4 CPU cores Hub Transport1 CPU core4 CPU cores8 CPU cores Unified Messaging 1 CPU core4 CPU cores Combined function 1 CPU core4 CPU cores Edge Transport1 CPU core2 CPU cores4 CPU cores

Megacycles per second Number of MHz that are required for a particular server Take an average CPU usage during the busiest part of the day Megacycles per mailbox = (Avg CPU * Speed of processors in MHz * Number of processors) / Number of mailboxes

Excessive CPU usage? Average processor usage stays above 70 – 80% during the busiest parts of the day

Memory sizing

RAM is the key to improving performance in Exchange Exchange 2003 ● 4GB of RAM per server ● User /3GB /USERVA=3030 in BOOT.INI file ● Large environments ● 2GB – 4GB of RAM for front-end servers and bridgehead servers For tuning information… ● See KB How to Optimize Memory Usage in Exchange Server 2003

Exchange 2003 and caching Exchange 2003 Extensible Storage Engine maximum cache ● 1.2GB of cache ● 576MB or 896MB by default 500 users on an optimized E2K3 server ● 2.4MB of cache per user 1000 users on an optimized E2K3 server ● 1.2MB of cache per user 2000 users on an optimized E2K3 server ●.6MB of cache per user

Exchange 2007 memory sizing Server roleMinimumRecommendedMaximum Hub Transport2GB1GB per CPU core (2GB minimum) 16GB Client Access2GB1GB per CPU core (2GB minimum) 8GB Unified Messaging 2GB1GB per CPU core (2GB minimum) 4GB Edge Transport2GB1GB per CPU core (2GB minimum) 16GB

Mailbox server roles Minimum of 2GB of RAM ● Minimum of 3GB of RAM if LCR is used ● Recommend 4GB of RAM Recommend 2GB + 5MB per mailbox for heavy users Can size memory based on number of storage groups, too. ● Add 2GB for each four storage groups ● Take whichever value is higher BOOT.INI optimization is not necessary 32GB maximum practical amount

Cache is essential If you follow recommendations for heavy users, each user will ALWAYS have 5MB of cache available Sufficient memory is essential to get expected disk performance Less available cache = More frequent disk I/O

Disk sizing

Introducing IOPS IOPS = Disk I/O operations per second ● Pronounced eye-ops Typical I/O capacity ● 10,000 RPM SATA drive = 70 IOPS ● 10,000 RPM fiber channel disk = 100 IOPS ● 15,000 RPM fiber channel disk = 120 IOPS ● 15,000 RPM SAS drive = 170 IOPS

Exchange 2003 IOPS Estimates User typeDatabase volume IOPS Light.5 Average.75 Heavy1.0 Large1.5

Exchange 2003 diminished cache performance MailboxesEstimated IOPS Calculated IOPS Required Actual IOPS Required Why? Less cache per mailbox

Exchange 2007 IOPS Estimates User typeDatabase volume IOPS Light.14 Average.20 Heavy.27 Large.41 *Assumes you are following Microsoft’s memory recommendations for Exchange 2007

Factors that affect IOPS Antivirus software Backups Outlook in cached mode LCR (estimates are 150% of database IOPS) Full text indexing (10% overhead for E2K7) Forms processing, work flow systems, or unusual messaging spikes Online maintenance Other server roles on same hardware (such as Hub Transport) Paging Connectivity / protocol logging Messaging records management

Transaction Logs and IOPS Microsoft’s estimates are for databases only Transaction logs may generate 10 – 25% additional I/O

Viewing Disk Transfers/sec

You can help! Use the maximum amount of practical memory for Exchange mailbox servers Sizing disk on right sector ● Use DiskPart.exe ● See KB Configure caching controllers for 75% write / 25% read

Signs of a disk bottleneck Physical disk’s Avg. Disk sec/Transfer >.02 on a sustained basis Physical disk’s Disk Transfers/sec staying at a sustained level

Sustained I/O activity

Tools you can use Performance monitor Exchange Best Practices Analyzer Performance Tuning Analyzer Exchange Server JetStress Exchange Server Load Generator Exchange Server Stress and Performance Exchange Troubleshooting Assistant User Monitor Microsoft Operations Manager

Free eBook The Shortcut Guide to Exchange Server 2007 Storage Systems ● m/SGES2K7SS.htm m/SGES2K7SS.htm

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