dynamox
6 Thallium

Re: Ask the Expert: Performance Calculations on Clariion/VNX

Thanks, interesting the exception that they mention could be in every environment. Honestly i would rather have more paths (reasonable number of course) to give me more queues and experience slower failover times as that occurs very seldom.

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RRR
5 Osmium

Re: Ask the Expert: Performance Calculations on Clariion/VNX

I’m not sure on this one, but I think I heard a colleague of mine say (years ago) that VMWare ESX can only handle 1024 objects (related to storage). A LUN that uses 4 paths are 4 objects, so if you use 8 paths, eachg LUN will cost you 8 / 1000. I’ve seen ESX clusters with >100 LUNs. Any comment on this?

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JonK1
3 Silver

Re: Ask the Expert: Performance Calculations on Clariion/VNX

Guys, before we forget: Mark has arranged for us to expand this topic onto Twitter for tonight, 7-9PM CEST. Jump in if you like, hashtag is #EMCATE.

http://tweetchat.com/room/EMCATE

See you tonight?!

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dynamox
6 Thallium

Re: Ask the Expert: Performance Calculations on Clariion/VNX

RRR wrote:

I’m not sure on this one, but I think I heard a colleague of mine say (years ago) that VMWare ESX can only handle 1024 objects (related to storage). A LUN that uses 4 paths are 4 objects, so if you use 8 paths, eachg LUN will cost you 8 / 1000. I’ve seen ESX clusters with >100 LUNs. Any comment on this?

I would have to revisit ESXi storage admin guide to look at limitations.

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RRR
5 Osmium

Re: Ask the Expert: Performance Calculations on Clariion/VNX

Check!

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Jim_Hegner
2 Iron

Re: Ask the Expert: Performance Calculations on Clariion/VNX

RRR you are correct, ESXI supports 1024 paths on a server in total, so 4 paths to each lun means 256 luns maximum

I have attached a clip form the VNX unified storage integration with Vmware Vsphere best practices...

that document is a part of the VNX TA expert level curriculum.

ESXI.JPG

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RRR
5 Osmium

Re: Ask the Expert: Performance Calculations on Clariion/VNX

So as long as failovers aren’t an issue and handling 8 paths instead of 4 is ok, then go for 8 paths I guess, but I never encountered a production environment where 8 was a requirement. If failing over with 8 paths causes problems, go for 4.

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Mabro1
4 Beryllium

Re: Ask the Expert: Performance Calculations on Clariion/VNX

Indeed, in 10 minutes we kick off. Looking forward to it

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JonK1
3 Silver

Re: Ask the Expert: Performance Calculations on Clariion/VNX

#EMCATE What makes the 14+2 RAID6 more efficient than the older 6+2 RAID6 for NL-SAS?

A good question from victor over on Twitter...

So for starters, the bigger the RG is, the more data disks you'll have compared to parity disks. In the new situation you'll have the nett capacity of 14 drives to allocate to servers. In the older 6+2 groups you would have to make two groups and still only end up with the capacity of 12 disks. Using 4 parity disks instead of a total of 2. This is just the financial aspect...

Performance wise, a bigger RAID group (obviously ) contains more drives, which will yield you more performance. However, watch out for the downside of this: rebuild times will be longer with larger RAID groups. Or, if you're rebuilding on ASAP rate, the impact on your storage (bus, disks, SP for parity calculations) will be larger.

If you want the performance and low rebuild impact, keep the RG's small and use striped metaLUNs to get you the amount of disks (=IOPs) you need. But you'll pay for it with $$

RRR
5 Osmium

Re: Ask the Expert: Performance Calculations on Clariion/VNX

Better performance in the 14+2 compared to 6+2? If you look at it per GB the larger group performs a little less good!

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