[dm-crypt] dm-integrity and bcache

[dm-crypt] dm-integrity and bcache

[Robby Nelson]

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I was hoping to see if anyone had any experience with or warnings about
using mdadm raid 1 with dm-integrity as a backing device for a bcache
device. I apologize if this is a dumb question, I don't have a great
technical understanding of all these systems.

Cheers,
Robby

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Re: [dm-crypt] dm-integrity and bcache

[Milan Broz]

On 20/05/2019 23:34, Robby Nelson wrote:
> I was hoping to see if anyone had any experience with or warnings
> about using mdadm raid 1 with dm-integrity as a backing device for a
> bcache device. I apologize if this is a dumb question, I don't have a
> great technical understanding of all these systems.

Hi,

in general, this combination should work (and several people try to use dm-integrity
as a backing device for MD raid), but I see some issues that dmintegrity
reveals in MD subsystem.

I am not sure about stability of bcache, this project had maintenance issues
in the past, I do not use it. There is also dm-cache (that is also somehow integrated
in LVM), that is at least maintained by the same group of people as dm-integrity :)

Anyway, I think a better list to ask is dm-devel@redhat-com, there are many people
that use similar various storage stack combinations.

I do not expect super-performance with dmintegrity it the stack (it will always slow
down operation). If you see any stability issues, please report them to the list above.

Thanks,
Milan

Re: [dm-crypt] dm-integrity and bcache

[Robby Nelson]

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Thank you for the input.

It sounds like bcache is no longer being worked on as the dev is spending
time on bcachefs instead. I considered dm-cache but it seems you can no
longer use lvm snapshots with it.

I will take a look at that mailing list, thank you.

Integrity at the cost of a little performance is fine with me in this
application.

Thanks,
Robby

On Mon, May 20, 2019 at 11:27 PM Milan Broz <gmazyland@gmail.com> wrote:

> On 20/05/2019 23:34, Robby Nelson wrote:
> > I was hoping to see if anyone had any experience with or warnings
> > about using mdadm raid 1 with dm-integrity as a backing device for a
> > bcache device. I apologize if this is a dumb question, I don't have a
> > great technical understanding of all these systems.
>
> Hi,
>
> in general, this combination should work (and several people try to use
> dm-integrity
> as a backing device for MD raid), but I see some issues that dmintegrity
> reveals in MD subsystem.
>
> I am not sure about stability of bcache, this project had maintenance
> issues
> in the past, I do not use it. There is also dm-cache (that is also somehow
> integrated
> in LVM), that is at least maintained by the same group of people as
> dm-integrity :)
>
> Anyway, I think a better list to ask is dm-devel@redhat-com, there are
> many people
> that use similar various storage stack combinations.
>
> I do not expect super-performance with dmintegrity it the stack (it will
> always slow
> down operation). If you see any stability issues, please report them to
> the list above.
>
> Thanks,
> Milan
>

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