Re: [Xen-users] making a raid 0 on a domU

["J. Roeleveld" <joost@xxxxxxxxxxxx>]

On Friday 28 May 2010 10:28:53 Israel Garcia wrote:
> On Fri, May 28, 2010 at 10:23 AM, Jonathan Tripathy <jonnyt@xxxxxxxxxxx> 
wrote:
> > On 28/05/10 09:01, Israel Garcia wrote:
> >> Hi guys,
> >>
> >> Do you know if I can make a raid 0 with two hdd devices on a domU?
> >>
> >> I'm running debian lenny as a dom0.
> >
> > If you're talking about software RAID, sure you can!
> > Just use the 2 VHD's in a software RAID style.
> >
> > But RAID0? Stay away from that :) Especially on 2 VHDs
> 
> Yeap, I'm looking for better performance ..:-)
> 
> regards,
> Israel.
> 

Are the 2 VHDs on seperate physical disks?
If yes, why not run the RAID0 inside the DOM0 and export that as a single VHD 
to the DOMU?

 RAID0 won't give you better performance if the VHDs are on the same physical 
disk.
I have no intention of testing this, but I would actually expect worse 
performance if the images are not fragmented into each other in just the right 
way to have each consecutively read block in sequence:
Eg. <block1 on disk1><block1 on disk2><block2 on disk1><block2 on disk2>....

But I agree with Jonathan, RAID0 should only be used for filesystems where a 
lot of temporary storage is placed. 1 disk failure of the 2 and the entire 
filesystem is gone. That is not a good idea for important files.

--
Joost Roeleveld

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