Re: Mounting raid without a btrfsctl scan

[Goffredo Baroncelli <kreijack@xxxxxxxxx>]

On Sunday 16 May 2010, Sebastian 'gonX' Jensen wrote:
> On 16 May 2010 02:02, Tomasz Torcz <tomek@xxxxxxxxxxxxxx> wrote:

[...]
> I don't know if I mentioned it before, but my system
> spends at least 6 seconds in the initramfs before passing control over
> to my distributions initscripts. Part of it is obviously because of
> btrfs having to spend approximately 3 seconds probing for devices (I
> have a decent amount of devices). 


> However, btrfs does not have that
> many functions yet. Would it be possible to at least have partial
> functionality kernel side, so that an initramfs is not required for
> mounting RAID devices?

I think that the good question is: why a kernel probing should be faster than 
a user space probing ? 

I think that some reasons of the time required by the btrfsctl scan in user 
space are:
1) a scan performed via 'btrfsctl -a' scans every block device (cdrom and 
floppy included). I suggest to perform a scan via udev (see my previous post); 
that should be reduce the boot time.
2) the actual initramfs tools pay attention to wait that _all_ devices 
appeared. This requires a bit of time which is not related to the "user space" 
scan.

Comments ?

G.Baroncelli

> 
> > --
> > Tomasz Torcz              ,,If you try to upissue this patchset I shall be 
seeking
> > xmpp: zdzichubg@xxxxxxxxx   an IP-routable hand grenade.'' -- Andrew 
Morton (LKML)
> >
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