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3533
August 9th, 2011 01:00
VNX series - Storage Pool rebalance command?
Hi,
We are about to receive a VNX configured with the FAST licence and two tiers of storage, NL-SAS and SAS...
Because we have 2TB NL-SAS we are using the recommendation of 8 drive multiples configured in RAID 6...
A lot of people have mentioned to me the lack of functionality currently within storage pools, especially regarding rebalancing after adding drives to the pool...
So my two questions are!
Firstly can I create a LUN and specify on what storage type it goes on to and then not allow it to be moved at all regardless of its performance characteristics?
Secondly there are a few articles online that mention the lack of the rebalance command but I am wondering about this... I mean if for example I have 8 SAS and 8 NL-SAS drives and I put data on them in the 1GB chunks mentioned... then expand by adding some disks, then if the original data is getting hammered due to it not being wider striped then the FAST algorithms should see this and promote it up?
I am just not sure about the whole rebalancing LUN's combined with FAST operation... in my mind logically they cannot exist with each other?
Storagesavvy
474 Posts
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August 9th, 2011 16:00
Since you only have two Tiers in your pool you can pin specific LUNs to each tier..
There are 4 tiering settings in FASTVP : Highest Allocation, Auto-Tier, Lowest Allocation, and No Movement..
If you wanted to pin a LUN to the SAS tier, you would use Highest Allocation, for the NL-SAS tier, use Lowest Allocation. If you want to let the array figure it out on its own, use Auto-Tier.
Keep in mind, if the capacity of your highest tier (SAS in your case) can be completely consumed by the LUNs that are set to Highest Allocation, there will be no free space left in that tier for the Auto-Tier LUNs and hence those LUNs will remain in the lower tier (NL-SAS).
As far as rebalance… Today, VP on CX and VNX does not rebalance LUNs within a Pool for any reason. FASTVP does not add any rebalance feature either but the movement of FASTVP slices between tiers over time MAY provide some rebalance of the data. This depends entirely on the size of the pools and tiers, the workload of LUNs in the pool, the tiering settings, and time.
Richard J Anderson
Anonymous User
63 Posts
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June 20th, 2012 06:00
http://virtualgeek.typepad.com/virtual_geek/2012/05/vnx-inyo-is-going-to-blow-some-minds.html
Just in case you haven't heard about:
So – what’s new?
In Rich Napolitano’s keynote – the standout to me is the preview of the upcoming (2H’12) VNX software upgrade – codenamed “Inyo” (because code names are cool). This has 6 big features that will help our customers get more out of their existing infrastructure: