[lustre-discuss] Virtual servers

Jon Tegner tegner at foi.se
Thu Feb 16 12:59:35 PST 2017


The first result was indeed with the client on the node where the 
virtual instance hosted the MDS. When I switched to put the client on 
one of the machines where the virtual machine hosts one of the OSS 
performance look a lot more what I would have expected (i.e., decent 
scaling when going from one to two files). Guess my "hypothesis" was wrong!


On 02/16/2017 04:55 PM, Mohr Jr, Richard Frank (Rick Mohr) wrote:
>> On Feb 16, 2017, at 9:56 AM, Jon Tegner <tegner at foi.se> wrote:
>> I have three (physical) machines, and each one have a virtual machine on them (KVM). On one of the virtual machines there is an MDS and on two of them there are OSS:es installed.
>> All system use CentOS-7.3 and Lustre 2.9.0, and I mount the file system on one of the physical machines.
> Which machine of you mount the file system on?  Is it an OSS node or the MDS node?
>> Anyway, when evaluating the performance (using FIO) I expected to see an increased transfer rate when going from one to two simultaneous files in the tests, and I do see this, but only for very small file sizes (around 0.2 GB). On the "non virtual" file systems I have tested the effect of increased transfer rate as the number of files are increased is on the other hand easily verified.
> Have you tried mounting the file system on different nodes?  This could help determine if the problem is always the same or if it might be affected by the type of node (MDS vs OSS) that is being used for the client.
> --
> Rick Mohr
> Senior HPC System Administrator
> National Institute for Computational Sciences
> http://www.nics.tennessee.edu

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