Hi All,
Currently dracut (as configured in Fedora) will online everything it finds on the system (all Volume Groups, all mdraid sets, etc). While looking for the root fs.
This is not necessarily a good idea, esp not so when running on machine with lots of disks, or connected to a SAN. This also leads to issues when booting on headless machines with dmcrypt devices (which are not needed for the root fs).
So I would like to propose to add the necessary kernel cmdline paramters to grub.conf, to tell dracut to only online certain devices (those needed for /)
I would like to make this change soon (in plenty of time for RHEL-6 beta), my plan is to make anaconda write the needed cmdline options to grub.conf, as it already has all the necessary information in its devicetree, and already has a framework for writing kernel cmdline options for devices which need them (fcoe, iscsi, dasd, zfcp) as they cannot be autodiscovered.
This would mean that for new installs we would always use the online minimum devices needed dracut boot method.
For existing installs, we would still use the bring up everything method, as anaconda does not re-write grub.conf on a normal update, this would only affect F-12 -> F-13 updates, and should not be a problem there, as people running F-12 will already be using the bringup everything method, and that thus is working for them.
Feedback welcome.
Regards,
Hans
On Sun, 2009-12-20 at 13:35 +0100, Hans de Goede wrote:
So I would like to propose to add the necessary kernel cmdline paramters to grub.conf, to tell dracut to only online certain devices (those needed for /)
In my opinion, if this is done, it must be done asap. But I really think it's a bad idea to do this now. I know it affects boot time for a small number of users who don't reboot that often. Perhaps you have some indicator of how bad that problem is?
Jon.
Hi,
On 12/25/2009 06:53 AM, Jon Masters wrote:
On Sun, 2009-12-20 at 13:35 +0100, Hans de Goede wrote:
So I would like to propose to add the necessary kernel cmdline paramters to grub.conf, to tell dracut to only online certain devices (those needed for /)
In my opinion, if this is done, it must be done asap. But I really think it's a bad idea to do this now. I know it affects boot time for a small number of users who don't reboot that often. Perhaps you have some indicator of how bad that problem is?
This is not about affecting boot time, but about headless systems not booting when they have a luks volume somewhere (even if that is not needed for boot).
Or about assembling (and thus marking as dirty) (md) RAID arrays which do not belong to the system at all, when a system is connected to a SAN, etc.
This really is the right thing to do, and yes we should have done it earlier, but we definitely should do it before the RHEL-6 beta.
Regards,
Hans
On Thu, 2009-12-24 at 04:55 +0100, Hans de Goede wrote:
Hi,
On 12/25/2009 06:53 AM, Jon Masters wrote:
On Sun, 2009-12-20 at 13:35 +0100, Hans de Goede wrote:
So I would like to propose to add the necessary kernel cmdline paramters to grub.conf, to tell dracut to only online certain devices (those needed for /)
In my opinion, if this is done, it must be done asap. But I really think it's a bad idea to do this now. I know it affects boot time for a small number of users who don't reboot that often. Perhaps you have some indicator of how bad that problem is?
This is not about affecting boot time, but about headless systems not booting when they have a luks volume somewhere (even if that is not needed for boot).
Or about assembling (and thus marking as dirty) (md) RAID arrays which do not belong to the system at all, when a system is connected to a SAN, etc.
This really is the right thing to do, and yes we should have done it earlier, but we definitely should do it before the RHEL-6 beta.
Ah yes, good call. Thanks for looking at that.
Jon.
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