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I recently installed an SSD. Boot time is actually great. But I'm curious to know why it seems like it idles a lot before actually booting. I notice this on the HDD light, which is off for a few seconds after the Ubuntu logo appears and when it starts blinking you can tell it started booting.

I enabled bootcharts to be generated and I noticed they are different from the ones I see everywhere else because it seems to start doing things after 10 seconds pass.

It's not grub. All times are set to 0 on grub, and the Ubuntu logo appears quickly after I turn on the computer.

Edit 1

systemd-analyze's output:

Startup finished in 10.282s (kernel) + 9.525s (userspace) = 19.808s

systemd-analyze blame:

7.010s NetworkManager-wait-online.service
996ms dev-sda5.device
819ms gpu-manager.service
785ms systemd-cryptsetup@cryptswap1.service
621ms systemd-hwdb-update.service
582ms systemd-fsck@dev-disk-by\x2duuid-17b45d84\x2dc711\x2d4481\x2d8a55\x2d30622ad67311.service
285ms accounts-daemon.service
263ms ModemManager.service
[...]

Full list

Edit 2 I tried systemd-analyze plot, and this is the output. So It appears those 10 seconds is the kernel loading? so, it's normal then? I swear I've seen Ubuntu machines boot up in literally 2 seconds.

Bootchart

High res: http://goo.gl/Nggroi

  • 1
    Maybe try systemd-analyze blame – mchid Dec 2 '15 at 3:26
  • Thank you for that suggestion. I edited the question to include the output of that. It seems like NetworkManager-wait-online.service is taking 7s, but I don't see it on the bootchart – Nahuel Dec 2 '15 at 4:20
  • Please don't convert these images to .jpg ( or use a hosting service that does ) as it renders them nearly unreadable. – psusi Dec 2 '15 at 22:54
  • Yes, I know. I used the upload tool in the editor, I figured it would do that so I added a link to png versions of both bootcharts. – Nahuel Dec 3 '15 at 3:29
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Those 10 seconds are the initramfs loading, detecting hardware, and mounting your root fs. Ubuntu does not use systemd during this time so that is why no data is available. If you don't use any fancy partitioning you can try doing without it and this might save some time, or at least give usable bootchart data for that time, but it appears you are using an encrypted filesystem. Assuming that is your root filesystem, then an initramfs is required.

  • I see. I encrypted my home partition. Would using a non-encrypted partition help reduce/remove those 10 seconds? Again, this isn't really a problem, boot time is excellent for this machine, I just wanted to understand a little how it works and why it seems to idle or wait at the beginning. If it's detecting hardware, it seems logical for the disk to be idle I guess. – Nahuel Dec 3 '15 at 3:34
  • @Nahuel, if it is only your /home partition that is encrypted and not your root, then you do not require an initramfs. – psusi Dec 4 '15 at 1:13

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