[Lustre-discuss] Lustre & SQLite

[Michal Wesolowski]

Oleg, thanks for your support

m.

Oleg Drokin wrote:
> Hello!
> 
> On Feb 12, 2009, at 3:29 PM, Michal Wesolowski wrote:
>>> Yes, this is somewhat outdated.
>>> 1.6.6 and above have posix advisory locking working (though  
>>> performance is not ideal,
>>> especially if you have many clients doing a lot of locks on the  
>>> same file at the same
>>> time).
>> Do you mean file locking mechanism in Lustre doesn't perform as  
>> efficiently as on local system or is not yet optimized? Or is there  
>> any general impact on Lustre when at least one node has flock option  
>> turned on? For example additional burden on MDS or OSSes which  
>> results in lower IO/s performance.
> 
> It is both not very optimized and slower than local system since it  
> needs to send network rpcs for locking (Except for the localflock  
> which is same speed as for local fs).
> The performance impact would only be realized if not only you mount  
> with -o flock, but actually use posix locking, and mostly only in  
> those operations.
> There is no impact on OSS operations at all. The only MDS impact is  
> there is now a bit more processing to handle those locking RPCs.
> 
> Bye,
>      Oleg
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