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Understanding Cache

Hello,

I believe i'm hitting a problem with the cache?  I have a workflow that creates a new volume and i am manually deleting that volume later.  However, that workflow keeps erroring on subsequent runs because it thinks that volume already exists.  I took a look at storage.volume and see the volume still listed there.

How can i manage that cache better or force it to refresh either manually or programatically?

Thanks

Sean

Re: Understanding Cache

Hi,

The volume you have created is reserved for future provisioning actions from the WFA.

You can clean the reservations from the reservation screen ,or directly from the monitoring screen by clicking "Clean Reservation"

You can read more on reservations below

Reservations

You can use the OnCommand Workflow Automation resource reservation capability in workflows to

ensure that the required resources are available for successful execution of workflows.

The WFA commands have the capability to reserve the required resources and remove the

reservation after the resource is available in the WFA cache database, typically after a cache

  1. acquisition. The reservation capability ensures that the reserved resources are available for the

workflow until the reservation expiration period, which you have configured in the WFA

configuration settings.

You can use the reservation capability to exclude resources reserved by other workflows during

resource selection—for example, if a workflow that has reserved 100 GB of space on an aggregate is

scheduled for execution after a week, and you are executing another workflow that uses the Create

Volume command, the workflow that is executing does not take up the space reserved by the

scheduled workflow to create a new volume. In addition, the reservation capability enables

workflows to be executed in parallel.

When previewing a workflow for execution, the WFA planner considers all the reserved objects,

including the existing objects in the cache database. If you have enabled reservation, the effects of

the scheduled workflows and the workflows that are executing in parallel, and the existence of

storage elements are considered when planning the workflow. If a workflow fails because of

reservation created by another workflow and if you want to use the reserved objects for your current

workflow, you can clean the reservation made by the other workflow in the Monitoring window

Re: Understanding Cache

useful information.One question..

As you mentioned above.."You can use the OnCommand Workflow Automation resource reservation capability in workflows to ensure that the required resources are available for successful execution of workflows.

can you please give one example how to this?.

@ slair: Apologize if i m diverting the actual topic.


Re: Understanding Cache

Hi,

Every time a command is scheduled for execution a reservation is created .

Every time an SQL  filter (resource selection ) is execute it takes into consideration past reservation .

Example:

An array has 2 aggregate

Aggregate A - 100 GB free capacity

Aggregate B -  80 GB free capacity

Workflow logic :Search aggregate with most free capacity and create volume size of 40GB on it .

First execution :Aggregate A will be selected

Second execution : Aggregate B will be selected - The WFA identify that in Aggregate A 40 GB out of the 100 GB are reserved .

You do not need to do anything specific for this to happen - this works automatically during the workflow planning and execution

Hope it is clear

Re: Understanding Cache

Great.I understood.I will test this.Thanks.