Hi all, Can somebody help me with this issue of native io problem in rhel 6.1 ??? Im still stuck with this issue.. -----Original Message----- From: redhat-list-bounces@xxxxxxxxxx [mailto:redhat-list-bounces@xxxxxxxxxx] On Behalf Of Amit Tewari Sent: Wednesday, July 13, 2011 12:42 PM To: redhat-list@xxxxxxxxxx Subject: Poor native io performance on kvm guest in Rhel 6.1 Hi all, I am having following test setup where I run multiple guest os on a host machine on kvm. Host machine operating sysyetem- Rhel 6.1 Virtualization -KVM Guest operating system -Rhel 6.1 Number of guest os - 2,4 ,8 ,16 Storage - Lvm based storage for guest os(disk storage) RAM of guest machine-1 gb Im testing IO benchmark to evaluate Disk io performance of kvm guests using benchmark bonnie and iozone on 2 gb file size So these benchmark tools are run on guest machines. I tested the two benchmark results with following guest configuration file 1. <disk type='block' device='disk'> <driver name='qemu' type='raw' cache='none' io='threads'/> 2. <disk type='block' device='disk'> <driver name='qemu' type='raw' cache='none' io='native'/> Benchmark results of bonnie for and iozone is better for io=threads option as compared to io=native option However redhat 6.1 technical notes say than we should keep io=native option in guest configuration file for disk storage,because it gives better IO results. But in my case for file size of 2 gb performance of iothread is better for disk storage. So is the bug that was reported in rhel 6.0 fo native IO is still not solved on rhel 6.1. Please find the link below for looking at the bug that was found in rhel 6.0 https://bugzilla.redhat.com/show_bug.cgi?id=611205 Please find below data for comparison of io=thread and io=native option 1. Bonnie results tested on 2 gb filer size .ram size 1 gb, io=threads option in guest xml file on kvm ,number of virtual machines = 8 Bonnie sequential output Per Char(K/Sec) 49857.17 Block (K/Sec) 200353.38 Rewrite (K/Sec) 12028.58 Bonnie sequential input Per Char(K/Sec) 26358.50 Block (K/Sec) 39596.83 2. Bonnie results tested on 2 gb filer size .ram size 1 gb, io=native option in guest xml file on kvm ,number of virtual machines = 8 Bonnie sequential output Per Char(K/Sec) 48020.83 Block (K/Sec) 68927.33 Rewrite (K/Sec) 5150.92 Bonnie sequential input Per Char(K/Sec) 6387.88 Block (K/Sec) 23258.08 As we can see from the output that performance of io=threads is better than io=native on lvm based disk storage. But red hat says io=native is better. But in my test setup 8 virtaual machine are running , so can somebody throw some light that why red hat says native perfrmnace is better, ithink the bug has not been solved in rhel 6.1 .because io=thread ioption shows better results.. Regards Amit Tewari DISCLAIMER: ------------------------------------------------------------------------ ----------------------------------------------- The contents of this e-mail and any attachment(s) are confidential and intended for the named recipient(s) only. It shall not attach any liability on the originator or NECHCL or its affiliates. Any views or opinions presented in this email are solely those of the author and may not necessarily reflect the opinions of NECHCL or its affiliates. Any form of reproduction, dissemination, copying, disclosure, modification, distribution and / or publication of this message without the prior written consent of the author of this e-mail is strictly prohibited. If you have received this email in error please delete it and notify the sender immediately. . ------------------------------------------------------------------------ ----------------------------------------------- -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list DISCLAIMER: ----------------------------------------------------------------------------------------------------------------------- The contents of this e-mail and any attachment(s) are confidential and intended for the named recipient(s) only. It shall not attach any liability on the originator or NECHCL or its affiliates. Any views or opinions presented in this email are solely those of the author and may not necessarily reflect the opinions of NECHCL or its affiliates. Any form of reproduction, dissemination, copying, disclosure, modification, distribution and / or publication of this message without the prior written consent of the author of this e-mail is strictly prohibited. If you have received this email in error please delete it and notify the sender immediately. . ----------------------------------------------------------------------------------------------------------------------- -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list
