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September 29th, 2009 23:00

Changing storage strategy

Hello,
is it possible to change existing storage strategy, and how? We are upgrading our Centera, and would like to change from Performance to Capacity, if possible.

Natasa

8 Posts

September 30th, 2009 00:00

We would change Content Protection from CPM to CPP as well.
Product Guide states that "It is not possible to change the protection scheme of data that has already been stored." Therefore I assume it might be changed for new data?

Natasa

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274.2K Posts

September 30th, 2009 05:00

Yes, it is possible to change the storage strategy from performance to capacity. This is a dynamic change (that is, it can be done online) and applies to content written after the setting takes effect. The same applies to change from CPM to CPP. That is, the change can be done online concurrent with customer activity. It applies only to new data written after the change take effect.

Keep in mind that there is a software license required to upgrade from CPM to CPP. Also, it is necessary that there be a minimum of 8 nodes in the cluster for CPP to work. Not only that, but it requires that there be 8 nodes in the cluster with free space. For example, let's say your customer started with a 4-node configuration. After a time, they filled these four nodes and are now planning to add four more nodes to cluster and want to convert from CPM to CPP. While you will be able to convert the cluster protection scheme to CPP, the Centera will not be able to store anything using CPP as there will only be four nodes in the cluster with free space on them (remember that the original four nodes are full). In this case, they would need to add 8 nodes to the cluster in order for CPP to work for them.

Dave Remaklus

September 30th, 2009 06:00

Hi Naty

Both changes need to be done with the GlobalServices Version of the viewer connected as emcservice.

set protection write parity thresholdvalue with m2 as fallback will configure all objects bigger than the configured thresholdvalue to be written in parity mode. Should not enough nodes be available Centera would store objects mirrored instead of not accepting them at all.
This is an enduser object/file size threshold value.

set feature storage-strategy capacity will set storage strategy to capacity.

Both settings apply objects written after the changes are made.

Best regards, Holger

8 Posts

October 11th, 2009 22:00

Thank you both!

Regards, Natasa
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