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2010
VNX8000 physical space requirements
I'm trying to plan for a deployment of a brand new VNX8000 and we need to account for future growth as we allocate floor space. I've been through a few different docs on this but I can't seem to find the answer I'm looking for. I know the backend configuration changed but I'm not sure how that might impact the overall physical expansion capabilities of the array. I also know that at launch the VNX8000 only supports 1000 drives. From that I think I can safely assume a maximum footprint similar to a fully loaded VNX7500 (maximum six racks).
I need to account for the potential future state (still to be delivered). So once the VNX8000 is capable of supporting it's target maximum number of drives, will that be acheivable using the standard 15 drive 2U DAEs? Or will it require a combination of the 25 x 2.5" drive DAEs and 60 drive DAEs? What would be the maximum number of cabinets for a fully loaded target state VNX8000?
Again, I know this is futures, but I have to account for potential future growth right now or we risk artifically limiting our expansion by deploying other hardware too close.
jeffwiggins
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October 2nd, 2013 08:00
Allen,
Here is some information that might help you with your location planning.
On the VNX8000 (and others) you will have max cable lenghts.
With regards to using different DAE's types that's fine, making the assumption that you use all the same DAE types here are the count limits assuming 1500 drive max
Max DAE#'s 25-drive (60), 15-drive (100), 60-drive (25)
Typically customers using the 60 drive DAE's are using EMC high density racks supporting a longer DAE and the proper cabling. It is possible to use non-EMC rack's for the dense DAE's subject to an RPQ approval.
Hope this helps.
Jeff.
Allen Ward
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October 2nd, 2013 08:00
So to use one of my favourite phrases "Just to be absolutely clear..." you are confirming that in the future state of the VNX8000 it will be possible to achieve 1500 drives using 100 of the 15 drive DAEs?
And yess I'm fully aware that that might not be optimal and desired, but I need to account for what is possible :-)
jeffwiggins
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October 2nd, 2013 09:00
Hi Allen,
Based on the information that is currently available, yes 100 trays of 15 drive DAE would be one option to get 1500 drives. Many drive types are letting customers leverage the 25 disk DAE to gain some rack efficiency. Of course the dae selection is all drive type dependent.
Also of note the 1500 drive support would be drive slots attached to the system.
if we look at a VNX5300 using only 15 drive DAE's it can only get to 120 drives. Using 25 slot dae's it can use all 125 supported drives. You can't go over the total drive slot counts, including the vault drives in the calculation.
Jeff.
Allen Ward
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October 2nd, 2013 10:00
I'm sorry Jeff, but I find the answer more confusing now. When you present the example of the 5300 it is based on the "old" architecture of FC backend busses and loops with the limitations of the number of busses and DAEs per bus for each model. So the VNX7500 for example could support 1000 drives, but without the use of higher density DAEs could only support 960 (8 backend busses X 8 DAEs per bus X 15 drives per DAE).
There is a new SAS backend for the VNX8000 that replaces some of the old loop technology with point to point connectivity. I haven't seen how this affects limitations of DAEs per bus, although I believe there is still the limit of 8 backend busses overall.
So the very clear questions are:
jeffwiggins
30 Posts
1
October 2nd, 2013 11:00
Sorry Allen, I'll try and clarify.
1)Once the VNX8000 supports 1500 drives the current support plan is to allow for 100 trays of 15 slot DAE's for the system. So YES supported once the VNX8000 is running the required firmware version.
Now, back to your example on the VNX7500. I had the number of drive/slot question come up before and unfortunately some of the documentation had errors.
Referencing first the VNX7500 Hardware information guide - it states 66 DAE's with a total of 960 drives - page 72
The Block and File (Unified) VNX7500 platform supports
After the release of the guide a clarification was issued via an EMC primus ticket emc292116 - The maximum is 10 enclosures with 250 drives per backend SAS port (Bus).
To get to the even 1000 drive slots you would need to mix some of the 15 slot DAE's and the 25 slot DAE's to hit the right drive slot limit.
ie 60 dae's x 15 dae slot = 900 slots + 4 dae's + 25 slot = 100 slots making a grand total of 1000 drive slots.
A VNX5300 can have 2 BackEnd buses
It can only have a max of 125 drives.
Any attempt to exceed the total SLOT count of 125 (adding up all the drives from BOTH BEs) will fail to configure
To max out the slots on the VNX5300 the configuration would need 4x 25 slot DAE's (including the 25 slot DPE)
Going back to the VNX8000, assuming 10 DAE's per bus, 15 drives means that the SPE would need to have at least 10 BE buses configured. Max BE /SP is 16.
Jeff.
Allen Ward
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October 2nd, 2013 12:00
Thank you Jeff. That does clarify things greatly. I guess I was thinking way back to the beinggings with the 8 DAEs per bus limitation. Sometimes it blends in together since I've been working on these beasts since the FC4700.
I appreciate your patience in this thread!