Navisphere Analyzer Question - SP Balancing

Question

I am monitoring our cx3-40f with Analyzer and notice that SPA is being utilized almost twice as much as SPB (60% vs. 25% averages). My understanding (still pretty new at the CLARiiON) is that we want both SP's to be balance or at least close to the same percentage.

I ran a LUN report and saw that SPB actually has about 15 more luns assigned to it than SPA.

My question is: is there an efficient way to determine which LUN's are the heavy utilizers so that I could move them over to SPB to balance the utilization more. I know the performance survey graph shows me by LUN, but I was wondering if there was something that would give a highest average utilization per day type listing.

Thanks.

chiodp · Answer

If you have NaviSphere analyzer you can collect a nar file for a period of 24 hours and if you looks at the single luns utilization during that period or also at the iops you can easily figure out which luns are the most busiest ones .

We always suggest to split the luns between the two sps in half . For example if you have 30 luns assign 15 to SPA and 15 to SPB .

This is an empiric method but works most of the time .

kelleg · Answer

If you set the Archive Interval (in Tools/Analyzer/Data Logging) to 600 seconds and set Periodic Archiving enabled and Stop After for 7 days, Analyzer will create an Archive about every 24 hours. You can then look at the NAR file - it will contain all the LUNs.

Rather then just Utilization, you should look at both Total IOPS and Total Bandwidth for each LUN - this will show you the load to each LUN - you should try to balance the LUNs based on load.

glen

gem_guy · Answer

So, the utilization metric is not valid here, or should we just not depend on it?

AranH1 · Answer

Correct, Glen is providing additional metrics that will give you a deeper understand of the load being placed on each SP.

If you just balanced the number of LUNs on each SP you wouldn't have a balanced performance (utilization, i/o, etc...) as not all LUNs will have the same load placed on them by the hosts. Monitoring the LUN performance will help you decide which LUNs need to be on separate SPs to balance the i/o load and help generate that nice even utilization metric.

kelleg · Answer

Utilization is useful to see where your activity is on the LUNs or the SP''s, but Utilization just means something is happening on the LUN, not now really busy it is. That's why you need to look at the LUNs (and the disks) for IO load (IOPS and Bandwidth).

Use the On-Line help for Analyzer, each of the values is described in detail. Also the Best Practices guide will help for deciding now to construct LUNs and Raid Groups.

EMC CLARiiON Best Practices for Fibre Channel Storage: FLARE Release 26 Firmware Update - Best Practices Planning

http://powerlink.emc.com/km/live1/en_US/Offering_Technical/White_Paper/H2358_clariion_best_prac_fibre_chnl_wp_ldv.pdf

EMC CLARiiON Fibre Channel Storage Fundamentals - Technology Concepts and Business Considerations

http://powerlink.emc.com/km/live1/en_US/Offering_Technical/White_Paper/H1049_emc_clariion_fibre_channel_storage_fundamentals_ldv.pdf

glen

CLARiiON

Navisphere Analyzer Question - SP Balancing

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