Are there any official information on MOS about hugepages in PV Linux on OVM?
How can we turn on this feature for PV Guest VM? We are running one big database and it has some problems with pagetables. SR is opened on that.
VM Server Linux ovsru0240vh021 188.8.131.52-45.6xen
VM Server grub.conf
title Oracle VM server (184.108.40.206-45.6xen)
kernel /xen.gz dom0_mem=11110M allowhugepage
module /vmlinuz-220.127.116.11-45.6xen ro root=UUID=cd09ac72-3ccc-4dba-b7f7-9d7caa44904d
I'm also interested in using hugepages for oracle database in Oracle VM environment.
Little bit experimentation(xen source code) and googling give me xen boot parameter allowsuperpage=1
Then with superpages = 1 in vm.cfg it was able to allocate HugePages in PV domU.
domU OEL 6 with 2.6.39-200.29.2.el5uek
AnonHugePages: 0 kB
Hugepagesize: 2048 kB
I didn't find any documentation, howto or examples using this in Oracle VM ( or generally with Xen).
Any informations about benchmarks, stability and status of support of hugepages(superpages) in Oracle VM are welcome.
I've got some informations about AMM and Hugepages(with ASSM).
We are preparing server (Oracle Vm hypervisor), that will host two large VMs (64bit OEL, 60+GB each). Each VM with cca 6 databases ( 2 with large SGA, rest smaller).
Ability to use huge pages give us the posibility to reduce pagetable walks and pagetablesize, so CPU and RAM savings.
I don't know what can give us the use of AMM in such a configuration?
AMM can partition the RAM between database instances.
I would definitely not recommend to use AMM in such configuration.
Please use MOS to read about Hugepages and AMM support. AMM is not supported with Hugepages. Only ASMM is supported.
You can read some valuable info about Linux, DB and memory management here: