Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I've just finished setting up a RAID 1 on my system. Everything seems to be okay, but I have a very slow boot time. It takes about three minutes between the time I select Ubuntu from GRUB and the time I get to the login screen.

I found this really neat program called bootchart which graphically displays your boot process.

This is my first boot (after installing bootchart). I'm not an expert at reading these, but it appears there are two things holding up the boot, cdrom_id and md_0_resync. I tried unplugging my CD drive SATA cable, and this is the new boot image.

It's faster, but it still takes about a minute, which seems pretty slow on this system. The md0 RAID device is my main filesystem. Is it true that it needs to get resynced on each boot?

I'm not sure how to diagnose my CD drive issue. The model is a NEC ND-3550A DVD RW drive. I should also note that there's a quick error message at startup about the CD rom. It's too quick for me to read it, just one line on a black screen saying "error: cdrom something something".

I'm not sure what other information to include. Thanks for any help.

share|improve this question
You can get some boot information from dmesg but it might be a large readout so you can read it directly: less /var/log/dmesg for example. Also check this file for errors: less /var/log/boot.log. There is a useful thread from ubuntuforums with good pointers on how to get information about your boot That bootlog switch (No/Yes) seems to be deprecated from some point on. – SaultDon Aug 13 '11 at 23:40
One more thing; on startup when you see that quick message - you can actually 'pause' by pressing Pause/End on your keyboard to stop the boot, then press it again to continue the boot. – SaultDon Aug 13 '11 at 23:46
My system isn't boot terribly slowly anymore. This is my newest boot image. There's not really one process that hangs up the boot, it just takes a long time. I've heard others complain that since Natty their boot has slowed. Mine's down to about a minute now. It just seems like it should be much faster especially on my system which is basically brand new (Core i7, 8GB RAM, X58 motherboard, etc.). – Kris Harper Aug 13 '11 at 23:57
up vote 1 down vote accepted

This turned out to be me being impatient. The software RAID controller needs to sync the drives after you install. I wasn't giving it enough time to do that. For large drives (e.g. 1GB or larger) this can take a few hours. Rebooting can actually stop this process and make it restart once the boot is finished.

To see the progress of the drive sync you can run

cat /proc/mdstat

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.