J_B1
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How to create TDATS if the new disks were added to an existing diskgroup?

The environment is VMAX 20K

E.g I currently have Diskgroup number 4 with 1TB SATAs which I used to create my t3_1tb thin pool (6+2).

If I decide to add more SATA drives to the existing diskgroup how do I create TDATS just from those specific new disks that were just added?

Any responses would be greatly appreciated.

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J_B1
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Re: How to create TDATS if the new disks were added to an existing diskgroup?

The end goal is to expand a thin pool that is slowly reaching its capacity. In order to do that I will need to create the TDATs first.

Lets say I have a diskgroup 4 with a 100 x 1TB SATA drives and I have created TDATs out of drives and used those TDATS to create my t3_1tb thin pool. EMC will install another 100 x 1TB SATA drives and put those in the same diskgroup 4.

My challenge is on knowing how to create the TDATs from whatever new spindles that will be installed.

If I use the following command, will that take in consideration just the new spindles that were just added in disk_group 4?

./symconfigure -sid xxxx -cmd "create dev count=2024, size=1001807 cyl, emulation=FBA, config=6 + 2, disk_group=4, attribute=datadev;"

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J_B1
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Re: How to create TDATS if the new disks were added to an existing diskgroup?

What do you mean if I have space on the existing 100 drives? The capacity on the existing drives is at 100%. I guess I am having a hard time visualizing how this procedure would work, my assumption was that once the TDATS are added to the thin pool then the data would rebalance.

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bhalilov1
2 Iron

Re: Re: How to create TDATS if the new disks were added to an existing diskgroup?

The symconfigure command above will do the job.

At the end it will give you the IDs of the new TDATs created, something like

Local:  COMMIT............................................Done.

      New symdevs: 2060:207F [DATA devices]

    Terminating the configuration change session..............Done.

Add them to the pool :

symconfigure -sid XXX -nop -cmd "add dev  2060:207F to pool t3_1tb  type= thin ; " commit

then enable and start rebalance :

symconfigure -sid XXX -nop -cmd "enable dev  2060:207F in pool t3_1tb type= thin ; " commit

symconfigure -sid XXX -nop -cmd "start balancing on pool t3_1tb ; " commit

J_B1
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Re: Re: How to create TDATS if the new disks were added to an existing diskgroup?

This would be the procedure after the TDATs are created. Thanks for sharing this.

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Quincy561
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Re: How to create TDATS if the new disks were added to an existing diskgroup?

It is important that every disk in the pool have the same number of TDATs, and they are roughly all the same size.

This may be somewhat difficult to achieve with Unisphere if you don't do some calculations up front.

J_B1
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Re: How to create TDATS if the new disks were added to an existing diskgroup?

That's a good point the current disks have 24 hypers each. When calculating cylinder size from the following command, should the cylinder size reflect the size of each TDAT or the whole disk?

./symconfigure -sid xxxx -cmd "create dev count=2024, size=1001807 cyl, emulation=FBA, config=6 + 2, disk_group=4, attribute=datadev;"


Also regarding the dev count should that take in consideration existing disks in the diskgroup that currently have TDATs or just the new disks that were added?


Thanks

J.B

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