Re: Hardware difference in the same Rack

[Mohamad Gebai <mgebai@xxxxxxx>]

On 2/21/19 1:22 PM, Fabio Abreu wrote:

Hi Everybody,

It's recommended join different hardwares in the same rack  ?

For example I have a sata rack with Apollo 4200 storage and I will get another hardware type to expand this rack, Hp 380 Gen10.

I was made a lot tests to  understand the performance and these new disks have 100% of utilization in my environment and the cluster recovery is worst than another hardware.

Can Someone recommend a best practice or configuration in this scenario? I  make this issue because if these disks not performing as hope, I will configure another pools to my openstack and maybe that's not make sense to me because I will split nova process in the computes node if I have two pools .

It's usually better to have homogeneous hardware across your cluster. Mixing hardware will cause your requests to will be subject to the "weakest link in the chain". For instance, write requests latency will be bound by the latency of your slowest device. In practice there might be other issues as well that have been pointed out on this list before (feel free to search).

Having separate pools on different kind of hardware sounds like a good approach. Otherwise, depending on your workload, it might be worth thinking about tweaking the primary affinity of OSDs so that your fast OSD are more likely to be primaries (reads are served from the primary OSD only). Depending on your new disks (throughput and size), maybe look at tweaking the weights. But that's just the beginning of a real hassle in terms of management.

Mohamad

_______________________________________________
ceph-users mailing list
ceph-users@xxxxxxxxxxxxxx
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com