Click on the calculator icon in the upper left-hand corner. A customer has a heterogeneous pool
with the following configuration:
1000 GiB of Flash, with 400 GiB free
10,000 GiB of SAS, with 2,000 GiB free
80,000 GiB of NL-SAS, with 20,000 GiB free
The customer creates a new LUN with data placement policy set to “auto-tiering”. The LUN is then
populated it with 500 GiB of data. How will that data be distributed (numbers are approximate)?
A.
300 GiB on Flash, 200 GiB on SAS, no data on NL-SAS
B.
166 GiB on Flash, 166 GiB on SAS, 167 GiB on NL-SAS
C.
9 GiB on Flash, 45 GiB on SAS, 446 GiB on NL-SAS
D.
400 GiB on Flash, 100 GiB on SAS, no data on NL-SAS
Important is : numbers are approximate !
So you don’t have to worry when you apply the ratio of the tiers to the size of the new LUN, with Auto-Tiering.
1,000+10,000+80,000 is the total size of the pool : 91,000 GiB
Flash Tier would receive 500/91*1=5.5 GiB
Sas Tier would get 500/91*10=55 GiB
NL-SAS would be allocated 500/91*80=440 GiB
As numbers are approximate, the correct answer is C
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Initial Slice Placement within a Tier
The tiering policies listed above affect the initial placement of a LUN’s slices within the
available tier. For example, initial placement with a pool set to “Auto-Tier” results in
the data being distributed across all storage tiers available in the tier. The distribution
of the data is based on the available capacity of the pool. If 70% of a pool’s free
capacity resides in the lowest available tier, then 70% of the new slices are placed in
that tier.
Answer C is the closest to this calculation. at 90%, 8% and 2% distribution.
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