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Date: Fri, 10 Apr 2009 12:48:35 +0200
From: John Hughes <john@Calva.COM>
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Subject: Re: [linux-lvm] Will LVM2 ever be able to do striped mirrors "raid
	10"?
References: <49DCA275.8070203@Calva.COM> <49DF02A7.50606@Calva.COM>
	<20090410101959.GA21846@us.ibm.com>
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To: LVM general discussion and development <linux-lvm@redhat.com>

malahal@us.ibm.com wrote:
> John Hughes [john@Calva.COM] wrote:
>   
>> John Hughes wrote:
>>     
>>>                if (lp->stripes > 1) {
>>>                        log_error("mirrors and stripes are currently "
>>>                                  "incompatible");
>>>                        return 0;
>>>                }
>>>
>>> Should I just stick with mdadm for my mirroring and striping needs?
>>>       
>
> You can do it today with some hassle or wait until someone implements a
> feature called 'generic layering'. The feature really means, treat some
> LVs as PVs!
>
> How can you do raid10 today? Create two raid0 LVs. Lets us call these
> lvgroup0/lv0 and lvgroup0/lv1. Now create raid1 lv in lvgroup1 where
> lvgroup1's PVs are lvgroup0/lv0 and lvgroup0/lv1.
>
> Isn't that a rai10 volume?
>   
To increase the chances of surviving a double-disk failure it would be 
better to raid-0 a bunch of raid-1's.

Are we sure there are no deadlock problems with LVM2 layered on top of LVM2?