emcmagic
2 Iron

Other than being used as tier in FAST VP, are they also being used for provisioning?

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I have 3 symtiers configured for FAST VP, and being associated 3 different VP POOLs,  EFD, SATA, and FC, respectively.

Among these 3 VP POOL's, only FC pool has bound thin devices. The other VP POOLs, EFD and SATA, only have enabled devices ( believe I can call them TDATA).

If I understand this picture correctly, Auto Provisioning is only used for FC VP pool, we are not using SATA pool for auto provisioning. Then my question is, how these SATA devices are provisioned, or are we use them as STD for provisioning, then how to verify that?

Appreciate your advice!

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Quincy561
4 Germanium

Re: Other than being used as tier in FAST VP, are they also being used for provisioning?

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With FAST VP, we generally don't recommend binding to the SATA pool.  You can use the allocation by policy feature to allocate on the SATA or EFD pool when bound to the FC pool. 

Not sure if the auto-provisioning will take advantage of that feature.

Same with the EFD pool, generally too expensive of a resource to bind to that tier.

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Quincy561
4 Germanium

Re: Other than being used as tier in FAST VP, are they also being used for provisioning?

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With FAST VP, we generally don't recommend binding to the SATA pool.  You can use the allocation by policy feature to allocate on the SATA or EFD pool when bound to the FC pool. 

Not sure if the auto-provisioning will take advantage of that feature.

Same with the EFD pool, generally too expensive of a resource to bind to that tier.

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emcmagic
2 Iron

Re: Other than being used as tier in FAST VP, are they also being used for provisioning?

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Thank you both for sharing.

Is this commonly practice to use SATA as just one of tiers in FAST VP?

How do I verify that SATA devices are not being used for provisioning at all. If I understand correctly, people could use them as STD to provision them as regular way.

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Quincy561
4 Germanium

Re: Other than being used as tier in FAST VP, are they also being used for provisioning?

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It is common to just use the SATA tier for FAST VP demotion.  Since the SATA tier generally can't support much IO, especially writes (new allocations will be 100% write workload), you don't want too much workload there otherwise the whole system could be impacted.  If you know the nature of the workload is mostly idle data that the SATA drives can support, you could put them directly into the SATA tier.

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Re: Other than being used as tier in FAST VP, are they also being used for provisioning?

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When used with FASTVP, you only need to bind to one tier/pool. In your case you are binding TDEVs to the FC pool, and then you apply a FASTVP policy to the devices. The Policy defines the rules under which FASTVP can move portions of the TDEVs into the other tiers.

You will end up with the FC pool appearing to be oversubscribed, but having free space, and the EFD and SATA tiers having 0% subscription, but having lots of data in them. This is normal for FASTVP and binding all TDEVs to the FC tier is recommended.

dynamox
6 Thallium

Re: Other than being used as tier in FAST VP, are they also being used for provisioning?

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emcmagic wrote:

Thank you both for sharing.

Is this commonly practice to use SATA as just one of tiers in FAST VP?

How do I verify that SATA devices are not being used for provisioning at all. If I understand correctly, people could use them as STD to provision them as regular way.

remember that STD devices are built on top of disk groups, not pools

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rohang1
2 Iron

Re: Other than being used as tier in FAST VP, are they also being used for provisioning?

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that's correct, Quincy56.

With FAST VP, the VP policy will take care of which of the 3 pools (or tiers contained in the policy) to get the thin device extent from and you'd only need to bind the TDEV to 1 of the available pools, generally the FC pool/tier.

Like you said, if you know that the nature of the workload is mostly idle, then creating TDEVs and binding them to the SATA pool would suffice.

Thanks.

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rohang1
2 Iron

Re: Other than being used as tier in FAST VP, are they also being used for provisioning?

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12.jpg

Hello emcmagic,

If you've created TDEVs and have bound them to the FC pool/tier, you could still have the TDEV using extents from the SATA pool/tier. This is when the FAST VP controller thinks you have extents that can be moved to the SATA tier because they're mostly idle.

To verify if there's a TDEV that is using the SATA (or the EFD tier) :

# symcfg show -pool <> -thin -detail -gb -sid XXX

Scroll down and Look at the "Other pool bound thin devices" section for the SATA pool .. If it lists one or more TDEVs, these are the TDEVs that have actually come from another pool/tier (the FC tier in this case) and are using extents from the SATA data devices (TDATs)

[In short, a TDEV bound to the FC tier is using extents from the SATA tier]

Another way to check if the TDEV (that is bound to the FC pool) is asking for extents from the SATA pool :

# symcfg list -tdev -range 5EcB:5EcB -bound -detail -v

Thanks.

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rohang1
2 Iron

Re: Other than being used as tier in FAST VP, are they also being used for provisioning?

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just for your reference ..

Another way to check if the TDEV (that is bound to the FC pool) is asking for extents from the SATA pool (and/or the EFD pool):

# symcfg list -tdev -range 016F:016F -bound -detail -v

image15.png

This is how, the output would look like, for TDEV 016F, that is bound to 1 pool/tier, but is requesting tracks from the other 2 pools contained in the policy.

Thanks.

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emcmagic
2 Iron

Re: Other than being used as tier in FAST VP, are they also being used for provisioning?

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Hi rohang,

Your messages are very helpful, and beyond what I am questioning on. Appreciate your help.

To make sure I understand you correctly. In your case, TDEV is bound to SATA_FASTVP, and asking, and asking only (not allocated yet) for extents from FLASH_FASTVP, and FC_FASTVP. correct?

the following is the result of running "symcfg list -tdev -range 0fa3:0faf -bound -detail -v". In my case here, TDEV is bound to FC_T1, and extents are actually allocated in ATA_T2. correct?

                  S Y M M E T R I X   T H I N   D E V I C E S

-------------------------------------------------------------------------------

                                   Pool        Pool          Total

                  Flags     Total  Subs     Allocated       Written

Sym  Pool Name    EMSP     Tracks    (%)  Tracks  (%)  Tracks   (%) Status

---- ------------ ----- --------- ----- --------- --- --------- --- -----------

0FA3 FC_T1        FX..    2209680     0         0   0   1269492  57 Bound

     ATA_T2       --.-          -     -   1269624  57         -   - -

0FA7 FC_T1        FX..    2209680     0         0   0   2207778 100 Bound

     ATA_T2       --.-          -     -   2207844 100         -   - -

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