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| any reason to separate 10k from 15k drives? https://3parug.com/viewtopic.php?f=18&t=77 |
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| Author: | bigiron [ Sun Aug 21, 2011 1:09 pm ] |
| Post subject: | any reason to separate 10k from 15k drives? |
I'm managing an F200 with a mix of NL, FC 10k, and FC 15k drives. The previous admin that initially setup the 3PAR created a FC CPG that has a filter of "-rpm 10," so when we added new 15k FC drives, they didn't become part of the existing FC_CPG. Is there any valid reason to separate the 10k drives from the 15k drives? I think by separating them, you're actually decreasing the overall performance of the system. If there's any valid reason to separate them please educate me. Also, in order to utilize both 10k and 15k FC drives in the existing FC_CPG I just have to remove the "-rpm 10k" filter and just select "default" right? This change can be done online and should not have any effect on existing LUNs. |
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| Author: | Richard Siemers [ Mon Aug 22, 2011 1:10 am ] |
| Post subject: | Re: any reason to separate 10k from 15k drives? |
So assuming you added the new 15k FC drives for capacity reasons, and not sub-volume tiering ... Yes, you will want to change your CPG(s) and perhaps even run some system tuner/dynamic optimizer commands to rebalance across all the drives. I recommend you call support and validate any changes you plan to make to a CPG containing live data, or get your 3PAR/HP sales engineer involved to help out. I personally, if it were my system, would create a new CPG with the -FC filter and no rpm filter, then using dynamic optimizer to move the luns to the new CPG, then delete the old CPG when it is empty. This will rebalance all your data evenly across all spindles, old and new and deliver optimal performance. If you don't have the license for that, contact your sales team for an 30 day eval to get the re-balancing work done. Without a rebalance, only your new data will take advantage of the new spindles... old data will continue to live on the old spindles, all new growth will eventually be limited to the new spindles. I hope this helps! |
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| Author: | bigiron [ Mon Aug 22, 2011 10:33 pm ] |
| Post subject: | Re: any reason to separate 10k from 15k drives? |
Thanks for that very good tip to create a new CPG, that sure looks like the best approach. I'll definitely confirm with our SE but he's out in vacation right now  Is the license you're referring to is Dynamic Optimization, we do have it on the system. |
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| Author: | Richard Siemers [ Tue Aug 23, 2011 11:36 am ] |
| Post subject: | Re: any reason to separate 10k from 15k drives? |
D.O. aka Dynamic Optimization, that is the one. When I finish moving luns around with D.O., I go back and "compact" the cpg that luns were moved out of to recover free space. |
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| Author: | bigiron [ Tue Aug 23, 2011 3:21 pm ] |
| Post subject: | Re: any reason to separate 10k from 15k drives? |
Got it. I started moving the VVs using tunevv in cli and I'm almost halfway done. I'm doing this on two F200 with 7TB used user space each. I'm only executing 3 tasks at a time since I'm not sure how many I can run simultaneously. I tried to use the -waittask option but it executed the task right away and didn't wait for existing tasks to complete first. I also notice that in 3PAR IMC GUI, the "Recent Tasks" list is listing the running tunevv task as "Tune Copy Space," this is misleading since I'm tuning the "user space" using the command "tunevv usr_cpg new-fc-cpg -f vv-name" I'm not sure why it's calling it "Copy Space" |
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