Fedora 16 beta vice Knoppix

[Lennart Poettering]

On Tue, 04.10.11 21:01, JB (jb.1234abcd at gmail.com) wrote:

> Results interpretation.
> -----------------------
> Knoppix won by a wide margin, while:
> - Knoppix having microknoppix fast-parallel boot (based on SysV/LSB scripts)
>   and DE with low resources usage and tailored for desktops

> - Fedora having systemd parallel boot and DE tailored for small and simple
>   devices

   ^^^^^ huh? Fedora is not tailored for that. Would be great of it it
   was, but that's simply not the case.

We install LVM and iSCSI and all kinds of other enterprisey stuff
on even the smallest netbook. And LVM is a major source of slowness,
since it requires all devices to be synchronously settled, before
"vgscan" can be called.

Also, we use SELinux and stuff which doesn't speed things up
either. SELinux has become a lot faster at boot in F16, so that's good,
but there's still a price to pay for it, which is more noticable the
weaker your machine is. That said, I do believe that SELinux is a good
thing and should definitely be part of the default install.

Another bigger source of slowness at boot is currently Plymouth which
also requires synchronous settling of devices (tough it's not as bad as
LVM in that regard though, but costs too since EDID probing is
apparently quite slow, and has every right to, but right now we delay
the boot processes for that but we shoudl really do that in the
background).

I have been asking for the removal of LVM from the default install since
a long time, and I am still firmly of the opinion that LVM needs to be
something that folks who want it enable but not something that slows
down everybody else's boot. 

If you want a quick boot on a netbook, then remove LVM, iscsi and the
other enterprisey storage stuff. Then run "systemctl mask
fedora-wait-storage.service fedora-storage-init-late.service
fedora-readonly.service fedora-storage-init.service
fedora-loadmodules.service fedora-autoswap.service
fedora-configure.service rc-local.service" to mask a couple of always-on
services, that are needed for enterprisey and legacy stuff. Also
consider disabling stuff like abrtd, or even rsyslog (if you do all log
output goes to kmsg, which reduces disk acesses and is often good
enough), and audit, cpupower, iptables, lldapd, mcelog, multipathd,
lvm2-monitor, mdmonitor, fcoe, dm-event. Check with "systemctl
list-unit-files" what's still left. Then shortcut the initrd by adding
"rootfstype=ext4" to your kernel cmdline amd replacing
"root=UUID=XXXXXXXXX" by "root=/dev/sda6" (or whatever your harddisk is
named in the kernel; what's important here is that the kernel can't look
for harddisks by uuid on its own, that's only done by the
initrd). Bypassing the initrd is well supported on F16 again, with one
exception: plymouth breaks, so disable that: "plymouth.disable=0" on the
kernel cmdline. On my netbook this gives me a bios-to-gdm bootup time of
around 10s, on my laptop of 5s, and Kay's newer laptop of < 3s. And it's
still an awesomely complete system, including SELinux and everything.

And if you compare that with Knoppix then you will still be comparing
apples and oranges, but we should be much more in the area of what
Knoppix provides as boot times.

I'd really like to see Fedora default to some more light-weight
choices. Not only for netbooks and suchlike having LVM and all the
enterprise stuff in the default is a bad choice, but for server VMs
which tend to more lightweight that's the case too. The goals of what is
needed to cope with netbooks and what is needed to cope with
lightweighter VMs are actually much closer then people might think, and
I'd love to see Fedora focus more on both.

Lennart

-- 
Lennart Poettering - Red Hat, Inc.