Re: [Xen-users] poor I/O with xen kernel

[Lennart Hansen <lennart.hansen@xxxxxxxxxxx>]

Anyone who can recommend where to go with this?

It's really demoralising seeing Raid controllers loose so much I/O even in Dom0.

We are seriously considering bare metal and docker for our applications if we 
can't solve this issue with I/O performance on Xen or worse yet Vmware *yikes* 
 

On Tue, 27 Jan 2015 16:04:24 +0000
Niki Vasilev <nikolay.vasilev@xxxxxxxxxxx> wrote:

> More info about this:
> 
> 
> filename: 
> /lib/modules/3.13.0-32-generic/kernel/drivers/scsi/megaraid/megaraid_sas.ko
> description:    LSI MegaRAID SAS Driver
> author:         megaraidlinux@xxxxxxx
> version:        06.700.06.00-rc1
> 
> this is the kernel and the driver version on both Xen and Non-Xen 
> version of Ubuntu Server
> 
> And this is the Xen kernel and driver version on CentOS
> 
> filename: 
> /lib/modules/3.13.0-32-generic/kernel/drivers/scsi/megaraid/megaraid_sas.ko
> description: LSI MegaRAID SAS Driver
> author: megaraidlinux@xxxxxxx <mailto:megaraidlinux@xxxxxxx>
> version: 06.700.06.00-rc1
> license: GPL
> 
> and the Intel Raid controller version:
> 
> 82:00.0 RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS-3 
> 3108 [Invader] (rev 02)
> 
> 
> ......
> 
> The Areca Raid Version is:
> 
> 02:00.0 RAID bus controller: Areca Technology Corp. ARC-1880 8/12 port 
> PCIe/PCI-X to SAS/SATA II RAID Controller (rev 01)
> 
> the Xen and non-xen Kernels are the same as above
> 
> is any body else is having this issue ?
> 
> Cheers,
> 
> Niki
> 
> On 27/01/15 13:28, Niki Vasilev wrote:
> > Hi there,
> >
> > I have some issues with Xen kernel on Ubuntu Server (latest) and CentOS 6
> >
> > I am using Intel RAID controller, testing with fio.
> >
> > On CentOS 6 I am getting ~14k iops with Xen Kernel and with the 
> > generic one I am getting ~15k (not much more ...). I played with 
> > drivers, changed the scheduler, etc....nothing helped.
> >
> > On Ubuntu Server with the default kernel and driver I am getting ~21k 
> > iops and when I boot with xen kernel I am getting ~10k ....its the 
> > same kernel version and same driver ...
> >
> > On the same machine with Areca raid controller with CentOS 6 and xen 
> > kernel I am getting ~26k iops
> >
> > My question is, how can I modified the kernel or what I have to 
> > install/config to solve this ...
> >
> > Cheers,
> >
> > Niki
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-users
> 



-- 
Lennart Hansen
System Admin Team Lead
lennart.hansen@xxxxxxxxxxx | +44 (0) 790 839 5692

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