Mailing List Archive

Does systemd work with mdadm?
OK,

I decided I'm going to try systemd to see what all the hubbub is about.
I know there are people on here that use it so I'm hoping someone's can
alleviate my concerns on it with mdadm.

I use an IMSM container (Intel fakeraid) as I dual boot with Windows.
This has happily worked for some time now.

I've googled around and it seems there could be a bug using mdadm and
lvm at the same time, but that's not what I'm doing. Considering when I
first set up this dual boot there was some configuration involved, I
don't believe I can just install it and pray it works as I've read if
systemd goes sideways you can't even log in.

Are there people running systemd and mdadm together that can comment? I
think I'm going to try anyway, and I have a suspicion that systemd is
going to bomb the first time it boots.

Dan
Re: Does systemd work with mdadm? [ In reply to ]
On Fri, 28 Nov 2014 16:15:45 -0800, Daniel Frey wrote:

> I've googled around and it seems there could be a bug using mdadm and
> lvm at the same time, but that's not what I'm doing. Considering when I
> first set up this dual boot there was some configuration involved, I
> don't believe I can just install it and pray it works as I've read if
> systemd goes sideways you can't even log in.
>
> Are there people running systemd and mdadm together that can comment? I
> think I'm going to try anyway, and I have a suspicion that systemd is
> going to bomb the first time it boots.

I'm not, I stopped using mdadm and LVM before I switched to systemd. But
it doesn't really matter if systemd does fail to boot properly, you can
switch back to openrc, fix the problem and reboot with systemd.

When I was testing systemd, I had to entries in GRUB, one with the
systemd init= option and one without, so I could boot with either.


--
Neil Bothwick

If at first you do succeed, try to hide your astonishment.
Re: Does systemd work with mdadm? [ In reply to ]
On Fri, Nov 28, 2014 at 4:15 PM, Daniel Frey <djqfrey@gmail.com> wrote:
> OK,
>
> I decided I'm going to try systemd to see what all the hubbub is
> about.
> I know there are people on here that use it so I'm hoping someone's
> can
> alleviate my concerns on it with mdadm.
>
> I use an IMSM container (Intel fakeraid) as I dual boot with Windows.
> This has happily worked for some time now.
>
> I've googled around and it seems there could be a bug using mdadm and
> lvm at the same time, but that's not what I'm doing. Considering when
> I
> first set up this dual boot there was some configuration involved, I
> don't believe I can just install it and pray it works as I've read if
> systemd goes sideways you can't even log in.
>
> Are there people running systemd and mdadm together that can comment?
> I
> think I'm going to try anyway, and I have a suspicion that systemd is
> going to bomb the first time it boots.
>
> Dan

mdadm works perfectly fine with systemd. I am running a 4-disk RAID-10
configuration and it gets assembled properly by systemd. I have the
"ARRAY ..." definition in /etc/mdadm.conf and the /dev/mdXXX mount
point in /etc/fstab and AFAICT that's all you need, the default
udev/systemd configuration brings it all up as expected.

--Mark
Re: Does systemd work with mdadm? [ In reply to ]
On 11/29/2014 12:19 AM, Mark Pariente wrote:
>
> mdadm works perfectly fine with systemd. I am running a 4-disk RAID-10
> configuration and it gets assembled properly by systemd. I have the
> "ARRAY ..." definition in /etc/mdadm.conf and the /dev/mdXXX mount point
> in /etc/fstab and AFAICT that's all you need, the default udev/systemd
> configuration brings it all up as expected.
>
> --Mark
>
>

I managed to get it going without too much trouble. I followed a guide
on the gentoo wiki but it didn't mention anything about setting up a
network, so I didn't.

When I rebooted that caused a mess but I was still able to log in. Fixed
that and added services that were enabled in openrc (like kdm...) and
everything's good to go.

So far, it's better than openrc in that there's a bug shutting down an
imsm raid that's still not been addressed. It causes the array to do a
rebuild next time it starts up and from my testing systemd doesn't have
this issue.

Dan
Re: Does systemd work with mdadm? [ In reply to ]
On Sat, Nov 29, 2014 at 8:44 PM, Daniel Frey <djqfrey@gmail.com> wrote:
>
> So far, it's better than openrc in that there's a bug shutting down an
> imsm raid that's still not been addressed. It causes the array to do a
> rebuild next time it starts up and from my testing systemd doesn't have
> this issue.
>

I can't speak to that particular bug but one of the nice things
systemd does if you're using dracut is that during shutdown systemd
will pivot back to the original initramfs and cleanly unmount root and
so on. This allows a complete shutdown of things like lvm/mdadm/etc
if done properly. When I first started using systemd I actually
noticed the improvements in shutdown more than startup (parallel
openrc is already pretty decent).

--
Rich