[Linux-cluster] dlm and IO speed problem <er, might wanna get a coffee first ; )>

[Wendy Cheng]

Kadlecsik Jozsef wrote:
>
> What is glock_inode? Does it exist or something equivalent in 
> cluster-2.01.00?
>   

Sorry, typo. What I mean is "inoded_secs" (gfs inode daemon wake-up 
time). This is the daemon that reclaims deleted inodes. Don't set it too 
small though.

>  
> Isn't GFS_GL_HASH_SIZE too small for large amount of glocks? Being too 
> small it results not only long linked lists but clashing at the same 
> bucket will block otherwise parallel operations. Wouldn't it help 
> increasing it from 8k to 65k?
>   

Worth a try.

However, the issues involved here are more than lock searching time. It 
also has to do with cache flushing. GFS currently accumulates too much 
dirty caches. When it starts to flush, it will pause the system for too 
long.  Glock trimming helps - since cache flush is part of glock 
releasing operation.

-- Wendy