[Trac-bugs] [PC-BSD Trac] #748: Slow boot - GRUB Takes 20 minutes to boot

PC-BSD trac at pcbsd.org
Thu Dec 12 04:45:48 PST 2013

#748: Slow boot - GRUB Takes 20 minutes to boot
  Reporter:              |      Owner:  Kris
  lordthrasher           |     Status:  new
      Type:  System      |  Milestone:
  Defect                 |    Version:  9.2-RELEASE
  Priority:  critical    |   Keywords:  grub, boot, slow, slow boot,
 Component:  System      |  loader, install, 9.2 release
  Configuration          |
Resolution:              |

Comment (by tobiastheviking):

 I can confirm this issue, and have a bit more data.

 I have hit this with both 9.2 and 10.X of PCBSD.

 This issue only hits when booting from the harddrive(on my setup anyways).
 The grub on the USB key (dd the USB/ISO file) boots within nominal time

 Once PCBSD has been installed though, i hit the same issue(total boot time
 for me is only like 5 minutes though, not 20).

 But, since i'm kinda insane, i decided i wanted to dualboot Debian from
 the same zpool as PCBSD. Installed debian, fought a bit with it, got it to
 boot properly. And then i installed the ZFS On Linux grub from debian.

 The ZOL grub from Debian installed in the harddrive again booted within
 nominal time limits. I have since(for various reasons) re-installed grub
 from PC-BSD, and it is now back to ~5 min boot time.

 During all this, i've made quite a few broken installs of grub, and had to
 fight my way through the "grub repair" stuff.

 When i'm in grub repair i do the following:

 set prefix=(hd0,msdos3)/pcbsd10/@/boot/grub
 insmod normal

 The "insmod normal" command takes about a minute to load(as does the
 normal command). To me it clearly looks like any and all harddisk access
 is slow. For some reason.

 I've trimmed my grub.cfg file quite a lot, removing fonts, graphics, etc.
 To make the wait time smaller. And it quite clearly works. For some reason
 data transfer from the harddisk is extremely slow.

 NOTE: Boot grub from the pc-bsd install disk, and doing a "configfile
 (hd0,msdos3)/pcbsd10/@/boot/grub" does NOT have any speed penalty. So
 while i feel certain that this issue has something to do with slow reads
 from disk(i guess it could be slow write to ram), the issue clearly
 happens early in the grub boot process, since the issue isn't hit when
 booting from external media.

 I'm not sure specifically what is different(in the code) between the grub
 i got from ZOL, and the one i got from PCBSD.

 If something relevant appears(possible patch, something that should be
 bisected) i'd be more than willing to to test it out.

 Another note, i've used the same usb key(that is, same release) on 3
 different computers. One of them has this issue(A Dell machine), One of
 them can't boot properly(2012 macbook air, different issues(s)) and the
 last one (ooooold white macbook) boots fine with PCBSD grub.


Ticket URL: <http://trac.pcbsd.org/ticket/748#comment:4>
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