Rawhide on Dell Mini 9

My new netbook arrived on Thursday, 13 days earlier than expected. Dell really need to work on their delivery estimates, but it’s better than having it be late…

This was one day after I came down with a really bad cold — still shrugging it off now. Productivity plummets to no end, but setting up a new computer is a more fun way to while away illness than reading a book (sorry, Orhan Pamuk; I think My Name is Red is your one masterpiece. The others are too meandering, especially when one can’t concentrate well).

The initial plan was to install Rawhide (ambitious!) over the CS department’s gigabit network, using the btrfs file system. This turns out to be unworkable — the r8169 driver mistakes the netbook’s 8101E as a gigabit adapter, whereas it’s only Fast Ethernet. I managed to get a DHCP lease once, on Dell’s Ubuntu installation.

Several network install attempts follow, over a 100 mbps link, using F11 alpha’s boot.iso. These all mysteriously fail, sometimes maddeningly close to completion. Even with ‘maxcpus=0 selinux=0’.

Giving up on this approach, I opted next for a hard drive install: use livecd-tools to put boot.iso into a thumb drive, and copy the ISO image to the drive’s root. It appears that this is insufficient — images/install.img has to be on the drive as well. This allows installation to succeed.

And then disappointment comes.

  • btrfs checksumming makes any RPM transaction mind-numbingly slow
  • Kernel panics. Even with maxcpus=0. This might actually explain the network install failures
  • Kernel panic at boot using newer kernels

So off with btrfs and on with ext4. Too bad; the SSD optimizations in btrfs look nice. One wonders if it’s the early production status, or if it does actually impose a certain amount of computational overhead making it unsuitable to netbooks (or any single-core computers, for that matter. No, hyperthreading does not count).

I’ve had a fully up-to-date Rawhide all of Sunday and it’s a joy to use. 512 MB is rather usable, albeit forcing a certain discipline when it comes to browser tabs. Will put in the 2GB upgrade when the new wireless card arrives, so I don’t have to open the hood twice. Ironically, that card shipped promptly but has since been wandering the limbo of Chinese customs… why is it that the cool electronics products inevitably come from Chinese eBay sellers…

Remaining bugs:

2 responses to “Rawhide on Dell Mini 9

  1. Can you elaborate on the Btrfs checksumming and performance of RPM transactions? How did you determine this to be a problem? What kind of performance difference were you getting compared to ext3? Have you filed a bug about this with the Btrfs developers? It sounds like something that would impact and matter to a lot of (RPM) users.

    Thanks.

  2. I’ve not done any benchmarks, but suffice to say it’s *really* noticeable — the Atom is not a very fast CPU (1.6 GHz, in-order, single-core design, with hyperthreading to ameliorate pipeline stalls), and I’m guessing Btrfs developers have been testing on machines with a bit more oomph.

    Last time I checked, Btrfs support in Fedora kernels is not always stable; until it is stable enough (or the Btrfs team bless certain kernel versions as being tested), there are probably other more important things to focus on. But feel free to forward this to the Btrfs mailing list!