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From: Gionatan Danti <g.danti@assyoma.it>
To: LVM general discussion and development <linux-lvm@redhat.com>
Cc: "Janne Heß" <janne+lvm@hess.ooo>
Subject: Re: [linux-lvm] RAID-less parity?
Date: Tue, 14 Jul 2020 22:32:34 +0200	[thread overview]
Message-ID: <a17aaff832c68fd0814e5d2a94547c91@assyoma.it> (raw)
In-Reply-To: <20200714160556.GA16281@redhat.com>

Il 2020-07-14 18:05 David Teigland ha scritto:
> On Mon, Jul 13, 2020 at 04:34:52PM +0200, Janne Heß wrote:
>> However some of my systems are single-disk systems. For those, RAIDs 
>> are
>> not possible so I was thinking if LVM has some support for single-PV
>> setups with parity on the same PV.
> 
> Hi,
> 
> We didn't include integrity+linear because we didn't see much value in 
> it,
> since it would require going to backups in case of an integrity 
> failure.
> 
> dm-integrity will detect but not fix bit rot.

Hi, I really think error detection has value by itself.
So I would suggest implementing it.

> 
>> So is there any way to get a parity setup with the current state of 
>> LVM?
>> I was thinking of a RAID-4 with one PV but the current tooling (more
>> specifically lvcreate) doesn't let me do that.
> 
> It's not currently possible.  We had an implementation for this we 
> could
> bring back if there is enough interest, so we'd like to hear more about
> how this would be useful for you and others.

For this feature (parity+linear) I don't see much value: if a single 
physical devices fails hard, all bet of recovery are off. However having 
it can sometime be useful so, if implementing/maintenance cost are low, 
why not?

Thanks.

-- 
Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
email: g.danti@assyoma.it - info@assyoma.it
GPG public key ID: FF5F32A8

  reply	other threads:[~2020-07-14 20:44 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-13 14:34 Janne Heß
2020-07-14 15:15 ` Gionatan Danti
2020-07-14 16:05 ` David Teigland
2020-07-14 20:32   ` Gionatan Danti [this message]
2020-07-30 20:49   ` Janne Heß

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