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## Disk count in DMX 3

Hi All,

I am trying to understand the disk configuration in the below table.How we calculating the minimum and maximum number of disks ?

1 Solution

Accepted Solutions
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## Re: Disk count in DMX 3

The maximum drive count is dependent on how many storage bays are configured.  Up to 240 drives per bay.

The minimum drive count isn't as calculated as neatly because the directly connected storage bays require vault drives, the daisy chained bays do not.  And there are rules, depending on specific configuration, on how many drives need to be populated before adding disk directors and/or storage bays.

9 Replies
3 Argentum

## Re: Disk count in DMX 3

The maximum drive count is dependent on how many storage bays are configured.  Up to 240 drives per bay.

The minimum drive count isn't as calculated as neatly because the directly connected storage bays require vault drives, the daisy chained bays do not.  And there are rules, depending on specific configuration, on how many drives need to be populated before adding disk directors and/or storage bays.

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## Re: Disk count in DMX 3

The maximum drive count is also a factor of the number of DA boards.  Each DA board pair can have some maximum number of drives.  There are also valult considerations.

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## Re: Disk count in DMX 3

I have two more question.

1. In above screen shot,it talking about 2 DA configurations.In that case are we configuring half of the storage bay ie,2 POD contain total of 8 DAEs ?

2.In a DAE how the total 15 drives are connected to the 2 LCC.are these 15 drives have connectivity to both the LCC cards ?

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## Re: Disk count in DMX 3

1. Correct.  The 1st pair is DA-1/DA-16.  They populate the bottom half of each of their respective bays.  They are fail-over for each other so they connect to the same drives/DAEs/PODS/Bays.

2. The drives are dual-ported, and are insterted in the front of the drive enclosure. Two LCCs plug into the rear of the encosure. Each drive connects to both LCCs.

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## Re: Disk count in DMX 3

Hi Michael,

So,In a 2 DA configuration there is should be only  one directly connected storage bay.DMX3 product guide says minimum number of drives in DAE is 4.So in that case 4 * 8 = 32 will be the minimum drives count.Considering the vault drive configuration count may vary.Just doing some math calculations

2.

Considering DA 1/16 configuration,one of the LCC, LCC A will be connected to the DA 1 and other LCC B  will be connected DA 16.If all drives connected to both the drives how these drives come under DA C/D loop.All these drives come under both DA or half drives in DA 1 and half drives in DA 16?

3 Argentum

## Re: Disk count in DMX 3

1. Technically you are correct, 4 / DAE required as absolute minimum for vault, or 32 total.  Such a minimum configuration would require an RPQ for consideration.  The numbers in that table may be the minimum for a standard config in the ordering system, and may also include some spares.

2. A particular DAE will be either C loop or D loop, not both.  The drives in the DAE alternate by which DA has primary/active control.  If first drive is DA-1, 2nd will be DA-16, 3rd will be DA-1 again, and so on.  If DA-1 or it's LCC or components between them fail, DA-16 will take control all drives in the DAE.

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## Re: Disk count in DMX 3

ok..

so, its like a active/passive kind of connection.first drive will have active connection to DA 1 and passive to 16.second drive passive with DA 1 and active with 16A.So if the DA 1 or its LCC fails, all drive become active in DA 16.

Is this correct ?

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