Thursday, June 07, 2007

Linux

If I'm intending on installing Linux, I suppose it would be worth it to collect up various links for things that I'm likely going to need to know.

For example, my US Robotics MAXg 802.11 PCI appears to be supported since it uses a BCM4318. But USB (which uses the BCM4320 / BCM2050) and cardbus are not yet supported (or maybe support is about there?) as of this writing (mid-2007). The USB is also identified as "Board: BCM94320R rev 3.1", which turns up a hit on google, but probably means it is based upon Broadcom's "AirForce One" reference design.

And then, of course, there are the free software drivers for the Intel graphics chipset, and various pieces of info floating around about it (like problems with video tearing). When something doesn't work, set the ModeDebug option in the xorg.conf file and post the config file and Xorg.0.log file. They also have a comprehensive developers guide on the X3000 chipset which probably would be good for their other chipsets as well.

And heaven forbid, if I ever have time to go into the kernal, here's a /. discussion of an article from IBM. IBM has a number of other possibly interesting articles.

I've seen mention that KDE integrates a lot of stuff better than GNOME, but that may not be true. There are two threads on ubuntu's forums about sizing the x-display as well - something a number of people seem to run into.

Musicmatch for Linux? Many people swear by amarok (with Sound Juicer or GRIP for ripping) - but it is KDE. Exaile is a GNOME version of that, with a ripper plugin: sudo apt-get install exaile Rhythmbox is quite popular as well, and Banshee is supposedly a cross between the two: sudo apt-get install banshee banshee-official-plugins (although some still prefer Exaile). There's another app called listen.

The big question is why Mythmusic isn't listed here.

Cool tips and tricks:
  • Some (AOL, of all companies) allow you to remotely mount free filesystem space by doing
    sshfs userid@members.aol.com: /some/directory
For a mail server investigate: maildirs (with "-T news" preset). On the topic of mail server(s), ePOST looks very interesting... encrypted and p2p for redundancy.

Here are some configuration items related to optimizing a Linux system for MythTV. For example, using RAID and one big file system to record multiple shows can result in massive fragmentation (is Storage Groups the answer?... or allocsize + running xfs_fsr at night. Also studies show that you need to keep at least x% free [5% on a 250G hd])? Is threaded writing the cause for the fragmentation? Speaking of which, the consensus appears to be that affordable RAID is best done via software. Hardware RAID, done right, is mighty expensive (starts at $250 and jumps to $400 and more very quickly). Ultra-320 SCSI array may actually still be worthwhile as well?! "Whatever you do, put a pair of hot-swap drive bays in your server" (which might mean using at least SATA 2.5). This guy did some interesting splits on his drives.

Restoring RAID:
Rebuilding the partition table is very easy.

sfdisk -d /dev/sda | sfdisk /dev/sdb (sda = good_disk, sdb = new_disk)
or
raidhotadd /dev/mdX /dev/sdX

Speaking of RAID, need to read and keep in mind that read errors are becoming more common as disks get larger.

Other interesting performance params: stripe_cache_size? Using 64 kByte block sizes. More complete list on this ubuntu-mythtv thread.

xfs (maybe with -o nobarrier and other tweaks for performance like noatime,nodiratime,logbufs=8,allocsize=512m) or reiserfs (version 4 or newer) are supposedly better file systems to use than ext3 for large file reasons. There seems to be differing opinions on LVM possibly causing problems, yet plenty of people use and love it, although with cavets (don't put more than one physical volume [PV] in an LV... PV's failing is not pretty). Check here on how to use pvresize to resize PV's. Installing LVM on Mythbuntu is outlined on the forums. I ended up doing and LVM over a RAID over xfs. Here's some step-by-step lvm manipulation.

Or ZFS with RaidZ2 support? ZFS has changed peoples lives? Except ZFS is only available as a (slow) userspace filesystem on Linux right now.

1TB drives are too expensive for me to be able to justify right now (~$260 for non-RAID, $100 or $150 more for RAID), so that means I'm going to have to go with smaller drives and grow/migrate the RAID later to a larger OR bigger drive, presumably using mdadm OR gparted. There is also something called resize2fs, and of course fdisk.

While on the topic of drives, backups and be live (snapshot), or not. And we need to secure the box, including mythweb and samba in particular.

Speaking of MythTV, I have another posting which is a random collection of lots of stuff... here I will collect more specific things.
  • Here's a discussion of light-weight window managers. blackbox/fluxbox appears to win his support.
  • Here's step-by-step for mini-myth on a thumb drive.
For sync'ing machines / offline files, rsync is the way to go. Here is a discussion.
Ubuntu Upgrades:
  • sudo aptitude install update-manager-core; sudo do-release-upgrade
  • -or-
  • update-manager to do it graphically
Linux driver guys live here. If I'm thinking about upgrading/hacking my own patches for the kernal, start at Kernal Newbie and "how to compile a kernel". There's also a forum thread and another blog entry. Looks like it might be a one step process now with kcheck, although it is perhaps not as optimized as it could be (at least, without manually changing a file?). USB driver info on the LinuxTV wiki. There's also a Custom Kernel build page on the ubuntu site.

More interesting stuff related to the Linux Kernel:
New topic: sound... specifically, remote sound. EsounD is one option (perhaps outdated). Polypaudio now? Looks like a long-standing topic.


New topic: Install/package stupidity. Ubuntu has dpkg, apt-get, synoptic, and aptitude. Each does something in a little different way. Some are more powerful than others. Graphical ones don't give you good error handling (check disk space before trying to install a kernal - or at least tell you what went wrong?). Avoid them and use the command line.

sudo dpkg-reconfigure mythweb
sudo aptitude reinstall mythweb

To reinstall, it's helpful to have a list of the installed packages.
dpkg --get-selections | grep -v deinstall > ubuntu-files (picks up purge pkgs)
-or-
dpkg –-get-selections | grep "\binstall" > ubuntu-files

then later:

sudo apt-get update
sudo apt-get dist-upgrade
dpkg --set-selections <> /home/user/location_on_remote/ubuntu-files

placed in /home/user/.local/bin, named package_list.sh and made executable.

"apt-get clean". Also try "apt-get -f update" to completely any unfinished business. apt-get install -f worth remembering as well. Then there is dpkg, and a summary of it along with apt-get.

aptitude seems more consistent than apt-get. More comparisons. aptitude has easier to read logs (in /var/log)

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