[lustre-discuss] how to mapping of RPC rate to bandwidth/IOPS?

[肖正刚]

Hi, Andreas
Thanks for your reply.
I am geting more clearer，now.

Thanks

Andreas Dilger <adilger at whamcloud.com> 于2020年6月10日周三 上午11:00写道：

> On Jun 2, 2020, at 02:30, 肖正刚 <guru.novice at gmail.com> wrote:
>
>
> Hi all,
> we use TBF policy(details:
> https://jira.whamcloud.com/secure/attachment/14201/Lustre%20NRS%20TBF%20documentation%200.1.pdf)
> to limit rpcrate coming from clients; but I do not know how to mapping of
> rpcrate to bandwidth or iops.
> For example:
> if I set a client's rpcrate=10，how much bandwith or iops the client can
> get  in theory?
>
>
> Currently, the TBF policies only deal with RPCs.  For most systems today,
> you are probably using 4MB RPC size (osc.*.max_pages_per_rpc=1024), so if
> you set rpcrate=10 the clients will be able to get at most 40MB/s (assuming
> applications do relatively linear IO).  If applications have small random
> IOPS then rpcrate=10 may get up to 256 4KB writes per RPC, or about 2560
> IOPS = 10MB/s.
>
> Cheers, Andreas
> --
> Andreas Dilger
> Principal Lustre Architect
> Whamcloud
>
>
>
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>
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