mdadm minimum kernel version requirements?

mdadm minimum kernel version requirements?

[Jes Sorensen]

Hi,

I bumped the minimum kernel version required for mdadm to 2.6.32.

Should we drop support for anything prior to 3.10 at this point, since
RHEL7 is 3.10 based and SLES12 seems to be 3.12 based.

Thoughts?

Jes

Re: mdadm minimum kernel version requirements?

[NeilBrown]

On Tue, 11 Apr 2023, Jes Sorensen wrote:
> Hi,
> 
> I bumped the minimum kernel version required for mdadm to 2.6.32.
> 
> Should we drop support for anything prior to 3.10 at this point, since
> RHEL7 is 3.10 based and SLES12 seems to be 3.12 based.
> 
> Thoughts?

When you talk about changing the required kernel version, I would find
it helpful if you at least mention what actual kernel features you now
want to depend on - at least the more significant ones.

Aside from features, I'd rather think about how old the kernel is.
2.6.32 is over 13 years old.
3.10 is very nearly 10 years old.
If there is something significant that landed in 3.10 that we want to
depend on, then requiring that seems perfectly reasonable.

I think the oldest SLE kernel that you might care about would be 4.12
(SLE12-SP5 - nearly 6 years old).  Anyone using an older SLE release
values stability over new functionality and is not going to be trialling
a new mdadm.

Thanks,
NeilBrown

Re: mdadm minimum kernel version requirements?

[Mariusz Tkaczyk]

On Tue, 11 Apr 2023 07:54:04 +1000
"NeilBrown" <neilb@suse.de> wrote:

> On Tue, 11 Apr 2023, Jes Sorensen wrote:
> > Hi,
> > 
> > I bumped the minimum kernel version required for mdadm to 2.6.32.
> > 
> > Should we drop support for anything prior to 3.10 at this point, since
> > RHEL7 is 3.10 based and SLES12 seems to be 3.12 based.
> > 
> > Thoughts?  
> 
> When you talk about changing the required kernel version, I would find
> it helpful if you at least mention what actual kernel features you now
> want to depend on - at least the more significant ones.
> 
> Aside from features, I'd rather think about how old the kernel is.
> 2.6.32 is over 13 years old.
> 3.10 is very nearly 10 years old.
> If there is something significant that landed in 3.10 that we want to
> depend on, then requiring that seems perfectly reasonable.
> 
> I think the oldest SLE kernel that you might care about would be 4.12
> (SLE12-SP5 - nearly 6 years old).  Anyone using an older SLE release
> values stability over new functionality and is not going to be trialling
> a new mdadm.
> 
> Thanks,
> NeilBrown

Agree with Neil. I have no strong recommendation. I'm not aware significant
feature that landed recently. I think that any kernel released around 5 ago
will be applicable.

Thanks,
Marusz

Re: mdadm minimum kernel version requirements?

[Jes Sorensen]

On 4/10/23 17:54, NeilBrown wrote:
> On Tue, 11 Apr 2023, Jes Sorensen wrote:
>> Hi,
>>
>> I bumped the minimum kernel version required for mdadm to 2.6.32.
>>
>> Should we drop support for anything prior to 3.10 at this point, since
>> RHEL7 is 3.10 based and SLES12 seems to be 3.12 based.
>>
>> Thoughts?
> 
> When you talk about changing the required kernel version, I would find
> it helpful if you at least mention what actual kernel features you now
> want to depend on - at least the more significant ones.
> 
> Aside from features, I'd rather think about how old the kernel is.
> 2.6.32 is over 13 years old.
> 3.10 is very nearly 10 years old.
> If there is something significant that landed in 3.10 that we want to
> depend on, then requiring that seems perfectly reasonable.
> 
> I think the oldest SLE kernel that you might care about would be 4.12
> (SLE12-SP5 - nearly 6 years old).  Anyone using an older SLE release
> values stability over new functionality and is not going to be trialling
> a new mdadm.

Hi Neil,

I guess my mindset is more that I don't expect RHEL/SLES grade distros
to fully upgrade mdadm, but I do see them backporting changes occasionally.

I was mostly basing my question on what I see us testing for in the
actual code. Dropping support for anything prior to SLES 12 (4.12) and
RHEL 8 (kernel 4.18) seems fair.

Cheers,
Jes

Re: mdadm minimum kernel version requirements?

[NeilBrown]

On Tue, 09 May 2023, Jes Sorensen wrote:
> On 4/10/23 17:54, NeilBrown wrote:
> > On Tue, 11 Apr 2023, Jes Sorensen wrote:
> >> Hi,
> >>
> >> I bumped the minimum kernel version required for mdadm to 2.6.32.
> >>
> >> Should we drop support for anything prior to 3.10 at this point, since
> >> RHEL7 is 3.10 based and SLES12 seems to be 3.12 based.
> >>
> >> Thoughts?
> > 
> > When you talk about changing the required kernel version, I would find
> > it helpful if you at least mention what actual kernel features you now
> > want to depend on - at least the more significant ones.
> > 
> > Aside from features, I'd rather think about how old the kernel is.
> > 2.6.32 is over 13 years old.
> > 3.10 is very nearly 10 years old.
> > If there is something significant that landed in 3.10 that we want to
> > depend on, then requiring that seems perfectly reasonable.
> > 
> > I think the oldest SLE kernel that you might care about would be 4.12
> > (SLE12-SP5 - nearly 6 years old).  Anyone using an older SLE release
> > values stability over new functionality and is not going to be trialling
> > a new mdadm.
> 
> Hi Neil,
> 
> I guess my mindset is more that I don't expect RHEL/SLES grade distros
> to fully upgrade mdadm, but I do see them backporting changes occasionally.
> 
> I was mostly basing my question on what I see us testing for in the
> actual code. Dropping support for anything prior to SLES 12 (4.12) and
> RHEL 8 (kernel 4.18) seems fair.

So where you say "dropping support" you don't actually mean removing any
code, but only that you will document somewhere that no effort will be
made support, or test against, earlier kernels. Is that correct?
Sounds reasonable to me.

NeilBrown

Re: mdadm minimum kernel version requirements?

[Jes Sorensen]

On 5/8/23 17:04, NeilBrown wrote:
> On Tue, 09 May 2023, Jes Sorensen wrote:
>> On 4/10/23 17:54, NeilBrown wrote:
>>> On Tue, 11 Apr 2023, Jes Sorensen wrote:
>>>> Hi,
>>>>
>>>> I bumped the minimum kernel version required for mdadm to 2.6.32.
>>>>
>>>> Should we drop support for anything prior to 3.10 at this point, since
>>>> RHEL7 is 3.10 based and SLES12 seems to be 3.12 based.
>>>>
>>>> Thoughts?
>>>
>>> When you talk about changing the required kernel version, I would find
>>> it helpful if you at least mention what actual kernel features you now
>>> want to depend on - at least the more significant ones.
>>>
>>> Aside from features, I'd rather think about how old the kernel is.
>>> 2.6.32 is over 13 years old.
>>> 3.10 is very nearly 10 years old.
>>> If there is something significant that landed in 3.10 that we want to
>>> depend on, then requiring that seems perfectly reasonable.
>>>
>>> I think the oldest SLE kernel that you might care about would be 4.12
>>> (SLE12-SP5 - nearly 6 years old).  Anyone using an older SLE release
>>> values stability over new functionality and is not going to be trialling
>>> a new mdadm.
>>
>> Hi Neil,
>>
>> I guess my mindset is more that I don't expect RHEL/SLES grade distros
>> to fully upgrade mdadm, but I do see them backporting changes occasionally.
>>
>> I was mostly basing my question on what I see us testing for in the
>> actual code. Dropping support for anything prior to SLES 12 (4.12) and
>> RHEL 8 (kernel 4.18) seems fair.
> 
> So where you say "dropping support" you don't actually mean removing any
> code, but only that you will document somewhere that no effort will be
> made support, or test against, earlier kernels. Is that correct?
> Sounds reasonable to me.

There may be a few removals, or at least checks for linux kernel being
more recent than X. Otherwise yes, not planning on proactively ripping
anything out.

Cheers,
Jes