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Theoretical maximum data rate on PER740xd with HBA 330 controller and 32x SAS 12Gbps disks

 

Hi,

We are planning to use our PER740xd nodes with HBA 330 controller and 32x SAS 12Gbps disks as Ceph OSD nodes.

I had a look at this document:

http://i.dell.com/sites/doccontent/shared-content/data-sheets/en/documents/dell-poweredge-raid-contr...

The HBA 330 connects to the host bus with a 8-lane, PCIe Gen3.

The 32x disks will be configured as non-RAID so Ceph will handle data protection. What's the theoretical maximum data rate that we can expect from the 32x disks?

Many thanks.

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Re: Theoretical maximum data rate on PER740xd with HBA 330 controller and 32x SAS 12Gbps disks

Slunav, 

 

With the drives and HBA the maximum data rate will be at 12 Gbps hardware wise, with Ceph we couldn't be certain as we don't support or use it.

 

Hope this helps.

 

Chris Hawk

Dell | Social Outreach Services - Enterprise
Get Support on Twitter @DellCaresPro 
Download the Dell Quick Resource Locator app today to access PowerEdge support content on your mobile device! (iOS, Android, Windows)

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Re: Theoretical maximum data rate on PER740xd with HBA 330 controller and 32x SAS 12Gbps disks

 

Thanks, Chris.

In here:

http://i.dell.com/sites/doccontent/shared-content/data-sheets/en/documents/dell-poweredge-raid-contr...

The document says:

  • Connectors: two x4 internal mini-SAS HD SFF8644
  • Data transfer rates: Up to 12Gbps per port; the total number of ports is 8

How are then the x32 12Gbps SAS drives connected to the 8 ports on the PER740xd? Can I use the iDRAC to find out?

Many thanks.

PS: The HBA 330 host bus type is: 8-lane PCIe Gen3 and its theoretical data rate is 7.88 GB/s or 63.04 Gbps (according to https://en.wikipedia.org/wiki/PCI_Express#History_and_revisions)

 

 

 

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Re: Theoretical maximum data rate on PER740xd with HBA 330 controller and 32x SAS 12Gbps disks

Hi,

 

Probably with this guide, you can refer to how the 32 drives are connected to the controller: Figure 143 Page 174: https://dell.to/30BubES;

 

 

I manage to find a whitepaper showing some architecture guides on R740XD and HBA330 but it's not using 32 drive configurations, but only 24 which is the front back plane: https://dell.to/3fexMMY

 

 


Thanks,
Joey Chong
Dell EMC Enterprise Support Services
Get support on Twitter @DellCaresPro

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Re: Theoretical maximum data rate on PER740xd with HBA 330 controller and 32x SAS 12Gbps disks

Thanks, Joey

I am sorry, I had a look at:

https://topics-cdn.dell.com/pdf/poweredge-r740xd_owners-manual_en-us.pdf

Figure 143, Page 174 as per your suggestion but I am still unable to find out how the 32 drives are connected to the controller.

Very interesting the reference architecture for Ceph!

Many thanks.

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