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August 13th, 2020 05:00
InsightIQ Capacity Forecast graph utilization
Hi, we have a 12 node Isilon cluster with two tiers on OneFS version 8.2.2.0 providing 1.72 PiB of storage. I need some advice on interpreting the Capacity Forecast group from InsightIQ (version 4.1.2.7) shown below.
The bit that is confusing me is that the graph shows writable capacity at 1.52PiB and the 90% mark at 1.55PiB. The writable capacity is 1.52TiB because we have VHS set at 10% which appears to be the default (I have another question about that for another post). I understand that best practice is to to leave 10% of available space for OneFS to use.
Am I correct in saying that if we use all the writable capacity then we will have used the 10% that we should be reserving for OneFS? If so, shouldn't the graph be showing the dotted line as 90% of writable capacity rather than 90% of provisioned? The 90% of provisioned seems very misleading.
Any insights welcome.
Ian
DELL-Josh Cr
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August 13th, 2020 11:00
Hi ianmi,
Page 309 https://dell.to/33ZYCGe
If you deselect the option to Ignore reserved space when calculating available free space (the default), free-space calculations include the space reserved for VHS
Let us know if you have any additional questions.
Phil.Lam
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August 14th, 2020 14:00
@ianmi,
You need 10% space for performance and upgrade reasons. You can cross 90%, but perfomance would degrade.
https://www.dell.com/support/article/en-us/sln319234/top-tips-every-admin-should-know-to-keep-their-isilon-cluster-healthy?lang=en
ianmi
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August 19th, 2020 05:00
Thanks Josh - we are running OneFS 8.2.2 but there is no option called 'Ignore reserved space when calculating available free space'. I only have (under SmartPool settings):
My problem isn't actually about VHS - InsightIQ seems to be calculating that correctly (green line). It is that the 90% line is calculated on total provisioned where as I think it would make more sense if this was 90% of writable capacity. I would expect the 90% threshold (dotted orange) to always be below the writable capacity so that it shows the capacity management team how much space is left before things become critical.
Knowing 90% of provisioned doesn't help at all.
Ian
ianmi
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August 20th, 2020 00:00
Hi PhilLam - thanks for responding. I understand that best practice is to to leave 10% of available space for OneFS to use and included that in my original post.
Ian