Hi Everyone,We are experiencing less than expected performance from our Exchange 2003 cluster, I was wondering if it was related to cluster size/disk alignment?We have a 2 node cluster running Exch2003 on a Dell/EMC 3-40 SAN. The write speed is fine, it seems to be the read speed that is slowish...below shows the current disk config. I would appreciate any comments.Best regards,Stuart.++++++++++++++++Description Disk drive Manufacturer (Standard disk drives) Model DELL PERC 5/i SCSI Disk Device Bytes/Sector 512 Media Loaded Yes Media Type Fixed hard disk Partitions 3 SCSI Bus 1 SCSI Logical Unit 0 SCSI Port 1 SCSI Target ID 0 Sectors/Track 63 Size 67.75 GB (72,744,376,320 bytes) Total Cylinders 8,844 Total Sectors 142,078,860 Total Tracks 2,255,220 Tracks/Cylinder 255 Partition Disk #0, Partition #0 Partition Size 39.19 MB (41,094,144 bytes) Partition Starting Offset 32,256 bytes Partition Disk #0, Partition #1 Partition Size 33.90 GB (36,405,089,280 bytes) Partition Starting Offset 41,126,400 bytes Partition Disk #0, Partition #2 Partition Size 33.81 GB (36,298,160,640 bytes) Partition Starting Offset 36,446,215,680 bytes Description Disk drive Manufacturer (Standard disk drives) Model PowerDevice by PowerPath Bytes/Sector 512 Media Loaded Yes Media Type Fixed hard disk Partitions 1 SCSI Bus 0 SCSI Logical Unit 3 SCSI Port 3 SCSI Target ID 2 Sectors/Track 63 Size 65.99 GB (70,860,787,200 bytes) Total Cylinders 8,615 Total Sectors 138,399,975 Total Tracks 2,196,825 Tracks/Cylinder 255 Partition Disk #6, Partition #0 Partition Size 65.99 GB (70,859,738,624 bytes) Partition Starting Offset 1,048,576 bytes Description Disk drive Manufacturer (Standard disk drives) Model PowerDevice by PowerPath Bytes/Sector 512 Media Loaded Yes Media Type Fixed hard disk Partitions 1 SCSI Bus 0 SCSI Logical Unit 2 SCSI Port 3 SCSI Target ID 2 Sectors/Track 63 Size 65.99 GB (70,860,787,200 bytes) Total Cylinders 8,615 Total Sectors 138,399,975 Total Tracks 2,196,825 Tracks/Cylinder 255 Partition Disk #5, Partition #0 Partition Size 65.99 GB (70,859,738,624 bytes) Partition Starting Offset 1,048,576 bytes Description Disk drive Manufacturer (Standard disk drives) Model PowerDevice by PowerPath Bytes/Sector 512 Media Loaded Yes Media Type Fixed hard disk Partitions 1 SCSI Bus 0 SCSI Logical Unit 4 SCSI Port 3 SCSI Target ID 2 Sectors/Track 63 Size 333.99 GB (358,622,208,000 bytes) Total Cylinders 43,600 Total Sectors 700,434,000 Total Tracks 11,118,000 Tracks/Cylinder 255 Partition Disk #7, Partition #0 Partition Size 333.99 GB (358,622,143,488 bytes) Partition Starting Offset 64,512 bytes Description Disk drive Manufacturer (Standard disk drives) Model PowerDevice by PowerPath Bytes/Sector 512 Media Loaded Yes Media Type Fixed hard disk Partitions 1 SCSI Bus 0 SCSI Logical Unit 5 SCSI Port 3 SCSI Target ID 2 Sectors/Track 63 Size 333.99 GB (358,622,208,000 bytes) Total Cylinders 43,600 Total Sectors 700,434,000 Total Tracks 11,118,000 Tracks/Cylinder 255 Partition Disk #8, Partition #0 Partition Size 333.99 GB (358,622,143,488 bytes) Partition Starting Offset 64,512 bytes Description Disk drive Manufacturer (Standard disk drives) Model PowerDevice by PowerPath Bytes/Sector 512 Media Loaded Yes Media Type Fixed hard disk Partitions 1 SCSI Bus 0 SCSI Logical Unit 0 SCSI Port 3 SCSI Target ID 2 Sectors/Track 63 Size 94.13 MB (98,703,360 bytes) Total Cylinders 12 Total Sectors 192,780 Total Tracks 3,060 Tracks/Cylinder 255 Partition Disk #3, Partition #0 Partition Size 99.00 MB (103,809,024 bytes) Partition Starting Offset 32,256 bytes Description Disk drive Manufacturer (Standard disk drives) Model PowerDevice by PowerPath Bytes/Sector 512 Media Loaded Yes Media Type Fixed hard disk Partitions 1 SCSI Bus 0 SCSI Logical Unit 1 SCSI Port 3 SCSI Target ID 2 Sectors/Track 63 Size 94.13 MB (98,703,360 bytes) Total Cylinders 12 Total Sectors 192,780 Total Tracks 3,060 Tracks/Cylinder 255 Partition Disk #4, Partition #0 Partition Size 99.00 MB (103,809,024 bytes) Partition Starting Offset 32,256 bytes

Did you run Jetstress before you deployed Exchange?Have your compared the performance counters against the thresholds described in thehttp://technet.microsoft.com/en-us/library/aa997270.aspx?Have you used a similar configuration as described inhttp://technet.microsoft.com/en-us/exchange/bb412165.aspxfor this storage model?

Stuart,From the looks of it, your disks are not aligned on the 4 KB boundary which is usually what happens when you don't use diskpart to set that when you import a disk. You can see anywhere up to a 15 to 20% performance hit because of this. If you take the starting offset for your last disk and divide it by 4096 you want this to come out to a whole number, it actually comes out to 7.875 meaning you are not aligned. Alignment is a destructive process to the data that is on the disk so I'm not sure what you can do now that you already have data on there and are experiencing a performance problem. Here are a few links about this that might help. Exchange Team Blog describing the reasons why and how to checkhttp://msexchangeteam.com/archive/2005/08/10/408950.aspxHow to use DiskPart at the command linehttp://support.microsoft.com/kb/300415How to Align on the Boundaryhttp://technet.microsoft.com/en-us/library/aa995867(EXCHG.65).aspxMy Personal Blog That Includes a few posts on the subject, take it for what it's worth, just some dude's blog that isn't ever updated ;)http://almostdailytech.com/?tag=disk-alignmentMy intial question I would ask is, is this a new install of exchange or an existing? If it's exsiting what has changed in the environment? How do you know it's read performance, are you using the counters that J-H pointed out? Do you know what the required IOPS you need for your environment is? What are the user performance profiles in your environment? Are the users in Cached Mode or Online Mode for Outlook? Do you have a Blackberry BES server in your environment? Mark Morowczynski|MCSE 2003:Messaging, Security|MCITP: Enterprise Support|MCTS:Windows Mobile Admin|Security+|http://almostdailytech.com

Hi Guys,Thanks for all your comments etc.It turns out that EMC recommended 64K as best practice, I have checked our disks and they all come out as whole numbers...Our current thoughts are now slow LDAP queries as being a factor, still looking into this though... also, we do not have memory optimization enabled as our servers come to a grinding halt after a few days... we have a job logged for this one...Oh... and having the SAN guys trying to create a mirror at 9:30 in the morning didn't help....Thanks,Stuart.

Stuart,To help pinpoint the performance problem try taking a look at this. It has ruling out various things, such as Active Directory. http://technet.microsoft.com/en-us/library/bb124328(EXCHG.65).aspxAlso try running the Exchange Best Practice Analyzer, this might show something else. The boot.ini file should have /3GB /Userva=3030 Mark Morowczynski|MCSE 2003:Messaging, Security|MCITP: Enterprise Support|MCTS:Windows Mobile Admin|Security+|http://almostdailytech.com