[lustre-discuss] E5-2667 or E5-2697A for MDS

[Dilger, Andreas]

On Sep 28, 2017, at 04:54, Forrest.Wc.Ling at dell.com wrote:
> 
> Hello :   
>  
> Our customer is going to configure Lustre FS, which will have a lot of small files to be accessed.
>  
> We are to configure 1TB Memory for MDS.
>  
> Regarding to CPU configuration , can we propose E5-2667 or E5-2697A for MDS for good performance ?
>  
> E5-2667 v4 : 3.2GHz, 8 Cores
> E5-2697A v4: 2.6GHz, 16 cores

There is a good presentation showing CPU speed vs. cores vs. MDS performance:

https://www.eofs.eu/_media/events/lad14/03_shuichi_ihara_lustre_metadata_lad14.pdf

Normally, higher GHz is good for the MDS, but if it reduces the number of
cores by half, it may not be worthwhile.  It also depends on whether your
workloads are mostly parallel (in which case more cores * GHz is better),
or more serial (in which case a higher GHz is better).

In this case, cores * GHz is 3.2GHz * 8 = 25.6GHz, and 2.6GHz * 16 = 41.6GHz,
so you would probably get better aggregate performance from the E5-2697A as
long as you have sufficient client parallelism to drive the system heavily.

Cheers, Andreas
--
Andreas Dilger
Lustre Principal Architect
Intel Corporation