HP ProLiant 4500 Performance of Microsoft Exchange Server 4.0 on Compaq ProLia - Page 20

LoadSim Score vs. # Users, Effect of increasing IS Buffer by 128 Mbytes

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444A/0696 WHITE PAPER (cont.) 2...0 PENTIUM PRO/166 EXCHANGE SERVER HARDWARE CONFIGURATION Machine Class Compaq ProLiant 5000 Processor Subsystem 1 Pentium Pro/166, 512 Kbyte L2 cache System Memory 128/ 256 Mbytes Disk Subsystem Integrated Fast Wide SCSI-2 controller Pagefile and executables volum:e1x2GB Fast Wide SCSI-2 drive PCI SMART-2 Controller Log volume: 2x2GB Fast SCSI-2 drives on port 0, RAID 1 (Array Accelerator enabled) IS volume: 3x2GB Fast SCSI-2 drives on port 1, RAID 5 (Array Accelerator enabled) Network Interface Compaq NetFlex/3 PCI (10BaseT) Operating System Windows NT Server v3.51 + SP4 Table 9. Pentium Pro /166 Exchange Server hardware configuration In this case, the IS buffers were increased by adding 128 Mbytes of RAM to the configuration. Note that the entire additional 128 Mbytes of RAM are allocated to the IS buffer, i.e. the IS buffers were originally set to 9833 (39 MB), and they were increased to 42601 (167 MB). Each IS buffer is 4 Kbytes in size, so a net of 32768 buffers are added to allocate 128 Mbytes of RAM. Score 4000 3500 3000 2500 2000 1500 1000 500 0 500 LoadSim Score vs. # Users Effect of increasing IS Buffer by 128 Mbytes (lower score is better) 1000 Number of Users 1500 39 MB 167 MB Figure 9. Performance benefit of increasing IS buffers. • The benefit of adding extra IS buffers produces significant benefit, especially at higher user levels. This is because the extra IS buffers are relieving the disk subsystem of a certain amount of the I/O load.

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W
HITE
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APER
(cont.)
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P
ENTIUM
P
RO
/166 E
XCHANGE
S
ERVER HARDWARE CONFIGURATION
Machine Class
Compaq ProLiant 5000
Processor Subsystem
1 Pentium Pro/166, 512 Kbyte L2 cache
System Memory
128/ 256 Mbytes
Disk Subsystem
Integrated Fast Wide SCSI-2 controller
Pagefile and executables volume
: 1x2GB Fast Wide
SCSI-2 drive
PCI SMART-2 Controller
Log volume
: 2x2GB Fast SCSI-2 drives on port 0, RAID
1 (Array Accelerator enabled)
IS volume
: 3x2GB Fast SCSI-2 drives on port 1, RAID 5
(Array Accelerator enabled)
Network Interface
Compaq NetFlex/3 PCI (10BaseT)
Operating System
Windows NT Server v3.51 + SP4
Table 9. Pentium Pro /166 Exchange Server hardware configuration
In this case, the IS buffers were increased by adding 128 Mbytes of RAM to the configuration.
Note that the entire additional 128 Mbytes of RAM are allocated to the IS buffer, i.e. the IS
buffers were originally set to 9833 (39 MB), and they were increased to 42601 (167 MB). Each IS
buffer is 4 Kbytes in size, so a net of 32768 buffers are added to allocate 128 Mbytes of RAM.
LoadSim Score vs. # Users
Effect of increasing IS Buffer by 128 Mbytes
(lower score is better)
0
500
1000
1500
2000
2500
3000
3500
4000
500
1000
1500
Number of Users
Score
39 MB
167 MB
Figure 9. Performance benefit of increasing IS buffers.
•
The benefit of adding extra IS buffers produces significant benefit, especially at higher user
levels. This is because the extra IS buffers are relieving the disk subsystem of a certain
amount of the I/O load.