[Linux-cluster] Performance tuning help sought

Kadlecsik Jozsef kadlec at sunserv.kfki.hu
Tue Mar 4 10:35:19 UTC 2008


Hello,

We have some performace problem in our GFS cluster. It manifests mostly in 
slow folder access in mail clients (pine, mutt) running on the nodes. When 
switching from one mailfolder to another, sometimes a large folder is 
loaded quickly - but usually a small folder, or even paging in the same 
folder takes a noticeable time. Looking at the performance tips of the 
GFS FAQ:

- we can neither preallocate files nor disable quota
- the cluster is alreay connected over 1Gb Ethernet
- statfs_slots is increased to 128
- dunno how to increase or decrease the cached GFS locks:
	- there is no /proc/cluster/ directory
	- how can one actually monitor the number of cached locks?
- the size of the filesystem is 1TB and was created with the default
  resource groups size. So recreating the filesystem with increased
  RGs size is one possible tuning option, as far as I see.
- breaking up the filesystem into smaller ones would make life much 
  harder for us, so if there are other possibilities we'd better avoid it

What can we do, besides increasing the RGs size? 
Is there any kernel parameter, which could be tuned (say vm parameters)?
Would it help to set higher MTU values for openais? (But how could one set 
it?)

Best regards,
Jozsef
--
E-mail : kadlec at mail.kfki.hu, kadlec at blackhole.kfki.hu
PGP key: http://www.kfki.hu/~kadlec/pgp_public_key.txt
Address: KFKI Research Institute for Particle and Nuclear Physics
         H-1525 Budapest 114, POB. 49, Hungary




More information about the Linux-cluster mailing list