Hello,

I had a query on FAST DP Storage policy.

FAST moves application data at the volume (LUN) level. Entire devices are promoted or demoted between Tiers based on overall device performance.

Eg:

Assume I have following Storage Tiers

# Tiers

EFD_TIER1

FC_TIER2

SATA_TIER3

# Policy

Gold_Policy : 10% EFD_TIER1

                     40% FC_TIER2

                     50% SATA_TIER3

# FAST SG ( Devices which are under FAST Control )

- CASE 1

Assume the devices are created from SATA DG

LUN1 - 100G

Q1/ Assume if there are more I/O demands, then what happens

      how it will move the LUN1 to say EFD or FC Tier, as the policy sets restrictions on the maximum allocation we can have from those Tier EFD / FC.

     

Q2/ As per the policy 10% should be on EFD, 40% FC & 50% SATA hence how will the initial allocation be spread across Tiers for 100G Lun. As capacity

      Alogrithem will alert saying out of capacity compliance issue.

- CASE 2

Assume the devices are created from SATA DG

LUN 1 - 100G

LUN 2 - 50G

LUN 3 - 50G

Q1/ How will the device spread across Tiers

Q2/ How does the device movement occur between tiers during more I/O requirement i.e which device will get promoted / demoted..

      Assume 100G device demand more I/O and need to move to FC Tier how will it occur as the policy says we can have only 10% of its storage coming

      from FC Tier.

Lastly..

What I have understood after going through the documents,

1/ Is it advisable to have 100% allocation to all tiers incase of FAST DP, so that device in the SG have flexibility to move across Tiers based on the IO requirement.

10G - LUN1

40G - LUN2

50G - LUN3

Assume the devices are created from SATA DG

Policy

EFD_TIER1 - 100%

FC_TIER2 - 100%

SATA_TIER3 - 100%

2/ Plan ahead the device which need more IO, its size and then define the policy.

 

10G - LUN1

40G - LUN2

50G - LUN3

Assume the devices are created from SATA DG

I expect 10G device will need more IO hence need to be on EFD, similarly 40G average good to have it on FC and lastly 50G less IO be it on SATA

Hence I will define policy according to my requirements

Policy

EFD_TIER1 - 10%

FC_TIER2 - 40%

SATA_TIER3 - 50%

3/ Have policy 100% and whichever LUN need more IO define the Tier percentage accordingly.

10G - LUN1

40G - LUN2

50G - LUN3

Assume the devices are created from SATA DG

I expect 10G device will need more IO hence need to be on EFD

Policy

EFD_TIER1 - 10%

FC_TIER2 - 0%

SATA_TIER3 - 100%

Appreicate if somebody can please help clarify my query on FAST, I'm not able to find much info on FAST DP compare to FAST VP.

any documents or links which gives more info the FAST DP will be highly appreciated.

Thanks

Yousuf.