[linux-lvm] RAID5 bug? [was: Re: raid and lvm]

[Jason Smith]

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On Wednesday 29 January 2003 04:26 am, Christophe Saout wrote:
> At the moment neither LVM1 nor DM (LVM2) can provide redundancy. But you
> can use LVM on top of the software raid5 driver in linux. I don't think
> there is another way at the moment.

Hi.  What is the best current answer to the canonical LVM plus software RAID5 
issue?  FYI, I'm talking about how the kernel's cache needs to correspond to 
the width of i/o requests.  When LVM controls a RAID5 PV, it will cause many 
differently-sized i/o requests to hit the array in parallel, basically 
forcing the kernel to flush the cache and rebuild continuously.  So, 
basically my array performs horribly once I create a snapshot volume.

I'm using LVM2.1.95.10 + 2.4.20-dm-7.

Some older LKML traffic explains the problem, but I haven't found an answer 
yet.

Thanks much.

- -- 
Jason Smith
Open Enterprise Systems
Bangkok, Thailand
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