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December 9th, 2013 02:00

Disk Groups in EMC Vmax

Hi ,

I am new to EMC Vmax array, I have few doubts

The Disk groups in Vmax contains drives and each drive is sliced in to hypers, as per my knowledge hypers from different drives with raid protection from a diskgroup forms a datadevice.

We can create data device using the command in symcli:

create dev count=1, size=203500.8, emulation=FBA, data_member_count=4, config=RAID-5, attribute=DATADEV, disk_group=SD;


My question  ,

data_member_count=4 , how does hypers are selected from DG to create sym data device, whtr hypers from same drive or different drives, do we need to set any configuration in bin file for this.

Can anyone explain this how it works , pls let me know if i am wrong.

2. Command to find Disks which are not part of any DISK_Groups.

Thanks and Regards.

4 Apprentice

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423 Posts

December 9th, 2013 05:00

Hello and Welcome to the Forums.,

to answer your question the VMAX algorithms will create the hypers on your array on different physical spindles ensuring that RAID members are not on the same physical spindles.   If you don't have disks to satisfy the request you will get an error telling you "could not find disks that satisfy our mirror/RAID policy"

There is no command to find disks that are not part of any disk groups.  Each disk when inserted in the array is configured into the bin file by your CE to be in one of the configured disk groups.

Hope this helps

6 Operator

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2.1K Posts

December 10th, 2013 01:00

Disk Group only contain the physical disks. I believe using the disk group to define the different technology (EFD, FC 15K, 10K, SATA) These different disk groups are created during BIN change.

Normally all the disk should be in disk group. During creating Symm device, the Enginuity will select proper and most suitable disk to meat your configuration. User is only able to select which disk group gonna be used to create symm device.

8 Posts

December 10th, 2013 03:00

Thank you all..

1 Rookie

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40 Posts

December 11th, 2013 21:00

data device means meta device ,where we can write data.one meta volume create with the help of few hyper volume .that's why hypers are selected from DG to create sym data /meta device.one single hyper volume  known as gate keeper.single hyper is not used to write data.In your command (dev count=1) it means u want to create 1 meta volume.(data_member_count=4) it means 4 hyper volume. (size=203500.8) this is single hyper volume size.so your meta volume size will be (203500.8x4)=814003.2  where u can write data.

now your doubt is clear ?

11 Legend

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20.4K Posts

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87.4K Points

December 11th, 2013 21:00

if only what you wrote made any sense.

1 Rookie

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40 Posts

December 13th, 2013 04:00

Can u write your question more simple ?

July 31st, 2014 11:00

seriously ! ?

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