I eventually installed Debian on a new desktop.

Sunday, 7 December 2014

Recently I build a new desktop system. The hightlights of the hardware are a pair of 512Gb SSDs, which were to be configured in software RAID for additional speed and reliability (I'm paranoid that they'd suddenly stop working one day). From power-on to the (GNOME) login-prompt takes approximately 10 seconds.

I had to fight with the Debian installer to get the beast working though as only the Jessie Beta 2 installer would recognize the SSDs, which are Crucual MX100 devices. My local PXE-setup which deploys the daily testing installer, and the wheezy installer, both failed to recognize the drives at all.

The biggest pain was installing grub on the devices. I think this was mostly this was due to UFI things I didn't understand. I created spare partitions for it, and messaged around with grub-ufi, but ultimately disabled as much of the "fancy modern stuff" as I could in the BIOS, leaving me with AHCI for the SATA SSDs, and then things worked pretty well. After working through the installer about seven times I also simplified things by partitioning and installing on only a single drive, and only configured the RAID once I had a bootable and working system.

(If you've never done that it's pretty fun. Install on one drive. Ignore the other. Then configure the second drive as part of a RAID array, but mark the other half as missing/failed/dead. Once you've done that you can create filesystems on the various /dev/mdX devices, rsync the data across, and once you boot from the system with root=/dev/md2 you can add the first drive as the missing half. Do it patiently and carefully and it'll just work :)

There were some niggles though:

  • Jessie didn't give me the option of the gnome desktop I know/love. So I had to install gnome-session-fallback. I also had to mess around with ~/.config/autostart because the gnome-session-properties command (which should let you tweak the auto-starting applications) doesn't exist anymore.

  • Setting up custom keyboard-shortcuts doesn't seem to work.

  • I had to use gnome-tweak-tool to get icons, etc, on my desktop.

Because I assume the SSDs will just die at some point, and probably both on the same day, I installed and configured obnam to run backups. There is more testing and similar, but this is the core of my backup script:


# backup "/" - minus some exceptions.
obnam backup -r /media/backups/storage --exclude=/proc --exclude=/sys --exclude=/dev --exclude=/media /

# keep files for various periods
obnam forget --keep="30d,8w,8m" --repository /media/backups/storage



Comments On This Entry

[gravitar] Jérémy

Submitted at 12:39:41 on 7 december 2014

I found dejadup to be a very nice and clean tool for scheduling encrypted backups - with notifications and stuff.

[author] Steve Kemp

Submitted at 15:12:58 on 7 december 2014

Thanks for the tip. For the moment obnam seems to suffice, but I'll bear it in mind for the future.

FWIW I've also started using xbindkeys to get the keyboard shortcuts I want working.

[gravitar] Faidon Liambotis

Submitted at 15:30:00 on 7 december 2014

Flashback's keyboard shortcuts issues is #771922, partly fixed now.

(fallback is called flashback now)

[author] Steve Kemp

Submitted at 15:37:16 on 7 december 2014

Thanks for the reference, and the update on the naming.

For the moment I've installed xbindkeys to give me shortcuts for opening a terminal ("Ctrl-Alt-T" is just too hard to unlearn!

(And for fun that lead to the filing of #772473 against xbindkeys-config.)

[gravitar] Josh

Submitted at 20:55:33 on 7 december 2014

What's the current state of obnam performance? Last time I tried it, it was still too slow to be usable. How long does a full/incremental backup take for you?

[author] Steve Kemp

Submitted at 21:08:45 on 7 december 2014

Performance was decent, but of course you have to bear in mind I'm reading from a pair of RAIDed SSDs so read-performance will be exceptionally good.

The limiting factor would probably be CPU overhead, or the speed of the external USB2 device I'm writing to.

To give concrete numbers, my root partition has about 10Gb of disk used. An incremental backup takes about 90 seconds.

[gravitar] Nemo Inis

Submitted at 02:01:58 on 8 december 2014

Re: obnam performance: Try using --lru-size=1024 and --upload-queue-size=512 (or even larger values if you have lots of RAM). The default values are too small, especially for backups larger than 100,000 files.

[gravitar] Nux!

Submitted at 11:15:41 on 8 december 2014

Considering that indeed the SSDs are likely to die in the same period and that you have backups, why waste them in a RAID1?

Go RAID0 or LVM. :-)

[author] Steve Kemp

Submitted at 11:19:47 on 8 december 2014

Given that the biggest advantage of SSDs is their read-speeds .. why not use mirroring to make them even faster? :P

Mostly using mirroring just because there is a slim chance they will fail at different times. Also because I'm used to providing redundancy.


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