New UCS Blade Deployment

[joeharb]

We are in the process of moving to the UCS platform for our Voice system.  We will be installing CallManager (Sub), Unity Connection and UCCX during the initial deployment.  Our Bill of Material has a pair of 146 GB drives in each of the Blades.  I am concerned that this is not going to be a enough drive sapce for the deployment.  Is it common/recomended to utilize SAN for the UCS voice deployments?

Thanks,

Joe

[Michael Owuor]

Joe,

If deploying UC on UCS B-Series platform, then you do have to have a SAN. There is not enough local disks to make DAS practical for UC applications. We need lots of spindles to ensure IOPS requirements are met.

Regards.

[joeharb]

Thanks for the reply, we have also recently purchased 600 GB drives that we were considering putting into the blades, I assume from your response that is is not a recommended approach.  Can you explain for about the spindles and IOPS as well as DAS?

Thanks,

Joe

[Michael Owuor]

Storage requirements for an application are a function of both capacity and the IOPS that should be met for the application. So even though the disks may provide needed capacity, if the applications' I/O demands are high, then performance is likely to degrade if the number of disks do not provide the required response time for I/O operations.

We have some IOPs guidelines documented here:

Storage System Performance Specifications

IOPS need to be sufficient to run the aggregate load that the VM’s on that server will generate. Assuming that you wanted to run 4 VMs per blade, CUCM, CUC, CCX and CUP, and assuming the following IOPS numbers for each application:

• CUCM VM IOPS ~200
• CUCn VM IOPS ~130
• UCCX VM IOPS ~150
• CUP VM IOPS ~60

So the total application IOPS requirement would be about 540.

With a raid group, the I/O are spread across the disks. So with just two disks, and with disks each rated at ~200 IOPS, total available IOPS would be ~400, which would not be enough to meet the application IOPS requirements. So you really don’t have a lot of room for scale here.

Compare that with a UCS C210 M2 TRC1 which uses local disks (DAS) and comes with 10x 146GB hard drives. IOPS = 200 * 10 = 2000

Regards,