Very good!

Digging a bit more into the ko2iblnd parameters, it seems the default for 
'map_on_demand' comes out as '1' - both on mlx4 and mlx5 boxes.
I was reading about earlier issues with in rdma, which supposedly pushed the 
default to 256 -  but that was perhaps to long ago.
Is it necessary to tune this parameter nowadays?

Regards
Thomas


On 1/30/22 20:41, Horn, Chris wrote:
Yes, this means the server has peer_credits=8, so can only accept that value. 
It informs the client of this so subsequent client connection attempt uses the 
lower value.
________________________________
From: lustre-discuss <[email protected]> on behalf of Thomas 
Roth <[email protected]>
Sent: Saturday, January 29, 2022 11:46 AM
To: [email protected] <[email protected]>
Subject: [lustre-discuss] 'queue depth too large', but connection works

Dear all,

test system: servers 2.12.7, and a client 2.12.6., all mlx4.

The client has some non-default ko2iblnd parameters, including 
"peer_credits=16".

I mounted my test system there and happily copied around some directories. Only 
afterwards I found
  > LNetError: 5278:0:(o2iblnd_cb.c:2551:kiblnd_passive_connect()) Can't accept 
conn from 10.20.3.64@o2ib6, queue depth too large:  16 (<=8 wanted)
in the MDS log.

I did read LU-3322, but obviously did not the point. "Can't accept conn" used 
to deny client access, but the MDS that didn't like my client just
created some ~25k new objects on behalf of that client.

Does this mean client and server negotiate a suitable value, but behind the 
scenes?

Regards,
Thomas
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