Exchange 2010 Jetstress

Hello,

Thanks in advance for any consideration given to this question.

We have six servers that we are preparing to deploy as two Exchange 2010 clusters. We are running Jetstress and we are seeing that some of the databases are performing worse than the others. In the most recent tests (below), the 'I/O Database Reads Average Latency ' was below 20ms for databases 1 to 32, but above 20ms for databases 33 to 40.

As these database are all on the same RAID10 volume being presented to Windows Server 2012, I cannot see why we should be seeing any significant performance variations between any of the databases. They are on the same volume but database latency varies from 13.2ms on the lowest to 27.8ms on the worst/

Can anyone provide an insight into why we should see a variation in the performance of databases stored on the same RAID volume and any thoughts on how we can improve performance?

<fieldset><legend>Database Sizing and Throughput</legend>

Achieved Transactional I/O per Second	517.008
Capacity Percentage	100%
Throughput Percentage	100%
Initial Database Size (bytes)	24012346884096
Final Database Size (bytes)	24013017972736
Database Files (Count)	40

</fieldset>
<fieldset style="width:900px;height:245px;"><legend>Jetstress System Parameters</legend>

Thread Count	2 (per database)
Minimum Database Cache	1280.0 MB
Maximum Database Cache	10240.0 MB
Insert Operations	40%
Delete Operations	20%
Replace Operations	5%
Read Operations	35%
Lazy Commits	70%
Run Background Database Maintenance	True
Number of Copies per Database	3

</fieldset>

 

Transactional I/O Performance

MSExchange Database ==> Instances	I/O Database Reads Average Latency (msec)	I/O Database Writes Average Latency (msec)	I/O Database Reads/sec	I/O Database Writes/sec	I/O Database Reads Average Bytes	I/O Database Writes Average Bytes	I/O Log Reads Average Latency (msec)	I/O Log Writes Average Latency (msec)	I/O Log Reads/sec	I/O Log Writes/sec	I/O Log Reads Average Bytes	I/O Log Writes Average Bytes
Instance3948.1	18.889	0.748	7.690	5.203	43670.414	36963.976	0.000	0.118	0.000	5.718	0.000	4788.514
Instance3948.2	16.938	0.830	8.659	4.569	43418.878	38615.803	0.000	0.113	0.000	5.463	0.000	4241.497
Instance3948.3	16.813	0.880	7.786	4.892	44561.641	36925.488	0.000	0.112	0.000	5.293	0.000	5929.639
Instance3948.4	16.613	0.912	7.738	5.172	49544.435	36399.381	0.000	0.110	0.000	5.329	0.000	4807.236
Instance3948.5	14.528	0.830	8.042	5.108	45691.347	37968.890	0.000	0.113	0.000	5.078	0.000	4226.354
Instance3948.6	15.797	0.774	7.841	4.417	42253.752	37838.610	0.000	0.109	0.000	5.183	0.000	4854.174
Instance3948.7	15.169	0.885	7.837	4.985	41899.236	37527.005	0.000	0.120	0.000	5.205	0.000	4920.579
Instance3948.8	13.208	0.860	8.876	5.167	42128.818	38869.609	0.000	0.113	0.000	5.712	0.000	4422.834
Instance3948.9	15.228	0.865	8.368	4.892	44826.443	37844.938	0.000	0.119	0.000	5.350	0.000	4563.473
Instance3948.10	14.703	0.838	7.232	4.703	46276.567	37751.927	0.000	0.110	0.000	4.607	0.000	4605.701
Instance3948.11	14.895	0.849	9.237	5.441	42987.246	36604.069	0.000	0.109	0.000	5.756	0.000	4394.979
Instance3948.12	14.919	0.880	8.080	5.108	39447.892	37405.489	0.000	0.117	0.000	5.467	0.000	4782.349
Instance3948.13	15.257	0.821	7.874	4.316	43579.232	37760.396	0.000	0.111	0.000	4.979	0.000	4763.041
Instance3948.14	16.043	0.900	8.156	4.939	45017.263	36239.237	0.000	0.114	0.000	5.266	0.000	4491.500
Instance3948.15	18.453	0.889	8.189	5.553	42929.584	37254.142	0.000	0.119	0.000	5.481	0.000	5027.673
Instance3948.16	19.477	0.847	8.494	5.019	43054.284	37871.949	0.000	0.110	0.000	5.569	0.000	4218.062
Instance3948.17	18.227	0.914	6.907	5.439	43438.850	36005.471	0.000	0.111	0.000	4.377	0.000	5306.598
Instance3948.18	16.698	0.837	7.629	5.200	41815.994	36626.540	0.000	0.109	0.000	5.240	0.000	4562.066
Instance3948.19	16.377	0.839	8.168	4.890	41162.932	36520.759	0.000	0.110	0.000	5.485	0.000	4310.137
Instance3948.20	16.028	0.762	9.417	3.732	44189.538	38476.940	0.000	0.113	0.000	5.506	0.000	4259.588
Instance3948.21	15.882	0.839	8.057	4.573	44574.210	37786.255	0.000	0.119	0.000	5.504	0.000	4672.439
Instance3948.22	15.725	0.834	7.259	4.685	48003.425	37688.659	0.000	0.118	0.000	5.141	0.000	4980.431
Instance3948.23	15.941	0.852	7.933	4.676	42161.632	38590.538	0.000	0.122	0.000	5.220	0.000	4762.992
Instance3948.24	15.965	0.844	8.600	4.563	44110.568	37657.570	0.000	0.121	0.000	5.429	0.000	5056.113
Instance3948.25	17.805	0.859	7.728	4.935	46655.130	36235.428	0.000	0.117	0.000	4.900	0.000	5099.254
Instance3948.26	16.278	0.912	8.581	5.320	45506.436	38606.864	0.000	0.118	0.000	5.278	0.000	4209.333
Instance3948.27	16.842	0.873	8.847	4.935	40179.215	38656.620	0.000	0.110	0.000	5.581	0.000	4058.415
Instance3948.28	17.393	0.850	7.843	4.585	45421.726	35889.823	0.000	0.107	0.000	5.280	0.000	4565.594
Instance3948.29	17.547	0.867	7.913	5.014	44368.517	37242.167	0.000	0.113	0.000	5.445	0.000	4367.294
Instance3948.30	17.879	0.857	7.959	4.788	42295.890	37868.129	0.000	0.109	0.000	5.349	0.000	4559.225
Instance3948.31	18.556	0.902	7.478	5.285	44551.939	36759.884	0.000	0.112	0.000	4.847	0.000	4724.664
Instance3948.32	19.159	0.860	8.441	5.020	44655.842	37811.654	0.000	0.114	0.000	5.651	0.000	4536.399
Instance3948.33	20.017	0.840	7.763	4.489	43454.115	38553.752	0.000	0.113	0.000	5.309	0.000	4520.340
Instance3948.34	20.943	0.879	7.747	5.371	46997.276	36928.814	0.000	0.126	0.000	5.317	0.000	4536.049
Instance3948.35	21.450	0.889	7.984	4.960	45732.749	38092.653	0.000	0.111	0.000	5.548	0.000	4795.407
Instance3948.36	22.044	0.819	7.318	4.835	45945.698	37727.545	0.000	0.108	0.000	5.215	0.000	4560.589
Instance3948.37	23.619	0.867	7.768	4.712	49172.024	37816.462	0.000	0.135	0.000	4.803	0.000	5201.788
Instance3948.38	24.341	0.800	8.022	4.495	43127.886	37162.078	0.000	0.115	0.000	5.569	0.000	4384.444
Instance3948.39	26.598	0.875	7.918	5.324	46341.585	36920.218	0.000	0.120	0.000	4.961	0.000	4678.788
Instance3948.40	27.842	0.853	7.067	5.249	48441.839	36131.505	0.000	0.112	0.000	4.844	0.000	5037.172

 

Any help is very much appreciated.

Thanks in advance,

Stuart

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