Re: sync guest calls made async on host - SQLite performance

[Matthew Tippett <tippettm@gmail.com>]

I have created a launchpad bug against qemu-kvm in Ubuntu.

https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/437473

Just re-iterating, my concern isn't so much performance, but integrity 
of stock KVM configurations with server or other workloads that expect 
sync fileIO requests to be honored and synchronous to the underlying 
physical disk.

(That and ensuring that sanity reigns where a benchmark doesn't show a 
guest operating 10 times faster than a host for the same test :).

Regards,

Matthew
-------- Original Message  --------
Subject: Re: sync guest calls made async on host - SQLite performance
From: Avi Kivity <avi@redhat.com>
To: RW <kvm@tauceti.net>
Cc: kvm@vger.kernel.org
Date: 09/27/2009 07:37 AM

> On 09/25/2009 10:00 AM, RW wrote:
>> I think ext3 with "data=writeback" in a KVM and KVM started
>> with "if=virtio,cache=none" is a little bit crazy. I don't know
>> if this is the case with current Ubuntu Alpha but it looks
>> like so.
>>    
> 
> It's not crazy, qemu bypasses the cache with cache=none so the ext3 
> data= setting is immaterial.
>