what if native systemd service is slower than old sysvinit script?

Ralf Corsepius rc040203 at freenet.de
Fri Sep 16 04:21:30 UTC 2011

On 09/15/2011 06:11 PM, Michal Schmidt wrote:
> On 09/15/2011 05:54 PM, Ralf Corsepius wrote:
>> On 09/15/2011 09:42 AM, "Jóhann B. Guðmundsson" wrote:
>>> On 09/15/2011 05:25 AM, Ralf Corsepius wrote:
>>>> Anyway, some more figures: On the same machine, bootup times when
>>>> booting from a (slow) external (IDE) USB2 HD:
>>>> - Fedora 15/i386: ca. 135 secs.
>>>> - Ubuntu 11.04/i386: ca. 70 secs.
>>>> [Here bootup time: Wirst watch measured time from "grub prompt" to
>>>> "login screen"]
>>>> It shows the effect of slow disks (60secs w/ internal HD vs. 2.15
>>>> minutes w/ USB HD), but raises questions on why Ubuntu appears to be so
>>>> much faster in this configuration.
>>> Could you run systemd-analyze plot>    bootup.svg and post it somewhere
>>> online
>> See: http://corsepiu.fedorapeople.org/scratch/bootup-20110915.1.svg
>    From the long delay before swap.target is reached it seems that your
> defined swap partition never comes up and systemd times out waiting on it.

Good catch! A bogus UUID for swap in /etc/fstab seems to have been the 
cause of this excessive bootup time.

After having fixed the UUID, bootup times of this configuration are now 
are at ca. 70 secs, i.e. at par with booting from internal HD.
Interestingly the Ubuntu setup had a similar UUID issue. After having 
fixed it there, booting Ubuntu now is at ca. 50 secs.

However, this questions the earlier claims related to the impact of 
disk-io speed on bootup times - If disk-io was the limiting factor on 
this HW, I'd expect booting from internal HD to be significantly faster 
than booting from an external USB-HD. Apparently this does not apply [1].


[1] Both setups' configurations are similar, but I haven't checked the 
details, yet.

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