[Lustre-discuss] lustre and small files overhead lru_size question

[Wojciech Turek]

Hi,

Lustre operation manual says that recommended values for lru_size  
parameter are in neighborhood of 1000 per osc and 2500 per mdc on  
interactively used client node.
Also it states.
Increasing this on a large number of client nodes is not recommended  
(this parameter controls locks cached on the client), though servers  
have been tested with up to 150,000 total locks (num_clients *  
lru_size).

My question is why not bigger values? What determines the max lru_size.
I would like to be able to determine what is the biggest number of  
lru_size I can set on a fixed number of interactive clients (login  
nodes) with fixed number of osc's and mdc's.

I found this thread where Oleg Drokin suggests to set lru_size to  
41000 (this is an old thread though). So it is significantly bigger  
value then one recommended in the manual.
http://lists.lustre.org/pipermail/lustre-discuss/2005-December/001040.html

Thank You,

Wojciech Turek
  
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