[pve-devel] switch to deadline scheduler by default

Alexandre DERUMIER aderumier at odiso.com
Wed Mar 14 13:17:56 CET 2012


>> Many feature only work with CFQ (ionice, openvz IO priorities), so this is not an option. 

Ok, din't know that.

I found an interesting article here :
http://publib.boulder.ibm.com/infocenter/lnxinfo/v3r0m0/index.jsp?topic=%2Fliaat%2Fliaatbpcfq.htm

recommandations for kvm and cfq for best performance are

/sys/block/device/queue/iosched/quantum = 32
/sys/block/device/queue/iosched/slice_idle = 0

Maybe can add them somewhere ?

----- Mail original ----- 

De: "Dietmar Maurer" <dietmar at proxmox.com> 
À: "Alexandre DERUMIER" <aderumier at odiso.com>, pve-devel at pve.proxmox.com 
Envoyé: Mercredi 14 Mars 2012 11:04:24 
Objet: RE: [pve-devel] switch to deadline scheduler by default 

Many feature only work with CFQ (ionice, openvz IO priorities), so this is not an option. 

> I see some user reports about io problem with cfq scheduler 

>From what I see, all those users run some very limited hardware. 

- Dietmar 

> What do you think about switching to deadline scheduler by default ? 
> 
> Also deadline perform with with virtio devices (this is the default scheduler for 
> rhev) For my iscsi san, it also perform better. 
> 
> just put 
> 
> 
> GRUB_CMDLINE_LINUX_DEFAULT="elevator=deadline" 
> 
> in /etc/default/grub 




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	Alexandre D erumier 
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