Re: Slow grub boot when /boot/grub is not on first partition

[Vladimir 'phcoder' Serbinenko]

Simon Wagner wrote:
> Hello dear GRUB2 developers,
>
> I am a user of Ubuntu 9.10, which uses GRUB2 1.97. Unfortunately GRUB
> needs a rather long time loading the modules. For 2 minutes or so it
> just displays "GRUB loading..." until the boot menu is shown and I can
> start Ubuntu.
>
> The bug has already been reported at Launchpad:
> https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/420933
>
> I tried to find out what causes the problem. I have the following disk
> layout:
>
> A "Windows HD" with the following partitions
> /dev/sda1
> /dev/sda2
> /dev/sda3
> /dev/sda4
> /dev/sda5
>
> A "Ubuntu HD":
> /dev/sdb2 (Extended Partition)
> /dev/sdb5 (swap)
> /dev/sdb6 (small partition, holds some misc data)
> /dev/sdb7 (Ubuntu 9.10)
> /dev/sdb8 (Backup)
>
> So when I add
>    set debug="disk"
> at grub.cfg I can see grub accessing the disk. It cycles through all
> the partitions, then reads data from sdb7, cycles again through the
> partitions, reads again from sdb7, and so on...
>
> I can't really tell whats causing this, I used the Ubuntu 9.04 package
> of grub2 before and that had not this problem. The package dates back
> to to the grub2 version from the 24th July of 2008.
>
> Maybe it is possible to do some caching in GRUB2? So for example, if
>    search -u someuuid
> is done, the result is saved, and if we do that again, we can lookup
> in the cache which drive has that uuid? The same for the FS type. If
> we once did detect ext2 on hd1,7 we should cache that, so we don't
> need to detect that again.
>
> I will try to add more grub_dprintf calls, so that I can better see
> what is going on.
>
> Sincerly
> Simon W.
>
We're aware of this problem and have patch which I'll merge as soon as
I'm back home
>
>
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>


-- 
Regards
Vladimir 'phcoder' Serbinenko
Personal git repository: http://repo.or.cz/w/grub2/phcoder.git