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VMAX Questions
Hi ,
I am working on redesigning virtual environment made of VMAX and VMware and would appreciate getting clarifications on following :
- In VMAX: Does LUN potential MAX IOPS changes with LUN size ?
Case in point : Comparing performance (IOPS/Latency) of 1 x 2 TB LUN vs. 2 x 1 TB LUNs assuming both have same number of metas , same allocation on each tier.
How same scenario plays out in case of VNX with pool made of 3 teirs.
- In VMAX: Does LUN potential IOPS change with number of metas in LUN? Example: Which LUN will give best performance given 1920 GB LUN ( 8 metas x 240GB) vs (16 metas x 120GB) vs (32 metas x 60 GB).
- Does VMAX perform better with less number of FAST policies ?
Background:
I have 3 policies (GOOD (100% SATA,10% Fiber) , BETTER (100% SATA,100% Fiber, 1% SSD) , BEST (100% SATA,100% Fiber, 100% SSD) . I am having performance issues due to storage groups under Fast Policy "GOOD" being trapped in SATA tier, and heating it up. I am thinking about eliminating the GOOD policy and keep only The BETTER and BEST policies with most of my SG are on BETTER, and only high performing servers (Oracle RAC) on BEST policy .
Any feed is much appreciated.
Thanks
Martin0904
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July 23rd, 2015 02:00
Number of Meta´s:
From my Point of view, the potential IOPS Change with the Number of Meta´s, but the Ideal Number for your Workload.... it depends. I use normaly 8 or 16 Meta´s for my bigger LUN´s, rarely 32. But i never did some Testing which gives me the best Performance. The Only thing i know, ist that anything over 32 will not realy gives more Performance.
I think for your Performance Questions you should open a call to your Sales Guy at EMC and do a Telco with a Speed Guru, every time i need such Deep Dive Informations i ask that guys.
VNX Scenario
Within VNX you should normaly see no difference beetween a 1TB or 2TB LUN as they are both striped over the whole Pool and have both the same LUN Queue Characteristics.