Linux Sig

General Discussion :: RE: 2010 Meeting Minutes

Author: waveclaw
Subject: 2010-05-6
Posted: Wed Jun 02, 2010 5:41 pm (GMT -6)
Topic Replies: 4

No meeting.

Several people showed. There was light discussion in the foyer.

General Discussion :: RE: 2010 Meeting Minutes

Author: waveclaw
Subject: Linux SIG 2010-03-04
Posted: Thu Apr 01, 2010 8:56 am (GMT -6)
Topic Replies: 4

Duplicating Posts with horrendous errors? Yummy Debug messages, too.

General Discussion :: RE: 2010 Meeting Minutes

Author: waveclaw
Subject: Linux SIG 2010-03-04
Posted: Thu Apr 01, 2010 8:55 am (GMT -6)
Topic Replies: 4

Linux SIG 2010-03-04

Last month was Android Phones.

This month is 'what to do with the SIG' and 'welcome to the lugnutz guys.'

Topic Brainstorming

What kinds of things to present?

Cellular Phone / Internet with Linux
Palm Pre
Cricket Devices (works with Ubuntu out of the box - recent version only)
Desktop Theming
Desktop environments
Desktop docks
Desktop doodads
10.04 - /etc/init.d and its replacement
Linux alternatives for windows stuff
open source on windows
wine
Knoppix re-mastering (bootable / live environment)
Linux distro overviews
cad/cam(eagle, etc)
Dia
Web design tools
Web browser parade
Development environments
Mail clients
Contact management on Linux
Filtering Spam or auto-filing
Linux community

lugnutz

The lugnutz local Linux user group has topics of a more advanced nature. May be of interest to some of the Linux SIG attendees as the SIG tries to focus on general interest and introductory material.

There is a new local "coco" facility at which some of the lugnutz people work, a Cooperative with many features useful for small businesses and the like. Has offices for rent. You can run a small F/OSS business out of it.

Process Improvements

The OKC Computer Group's Vice President of Special Interest Groups has an email list that may be interested in topics if they are announced ahead of time.

Wanting to get topics out ahead of time. Get the website updated. Take the sign-up sheets at try to put together at least some kind of email list.

Expect changes to the meeting format. Other presenters in particular.

General Discussion :: RE: 2010 Meeting Minutes

Author: waveclaw
Subject: Linux SIG 2010-02-04
Posted: Thu Mar 04, 2010 8:33 am (GMT -6)
Topic Replies: 4

I'm on-call at work this week and will not be able to attend and take notes.

General Discussion :: 2004 Installfest

Author: chad
Subject: 2004 Installfest
Posted: Sat Feb 20, 2010 11:52 pm (GMT -6)
Topic Replies: 0

Memories...

http://tinyurl.com/yc8gds7

General Discussion :: 2004 Installfest

Author: chad
Subject: 2004 Installfest
Posted: Sat Feb 20, 2010 11:49 pm (GMT -6)
Topic Replies: 0

Memories...

http://tinyurl.com/yc8gds7

General Discussion :: 2010 Meeting Minutes

Author: waveclaw
Subject: 2010 Meeting Minutes
Posted: Thu Jan 07, 2010 7:59 pm (GMT -6)
Topic Replies: 4

2010-01-04

Attendance
Lighter than usual due to the -20 wind chill outside.

Topic: Debugging Linux installs.

Randy has a new 20Gb Dell HV02T mp3 player and Ubuntu Linux 8.04 Linux.

Some music players can do dual mode: as a USB mass storage device or media device. For those that only support media devices Linux - and Windows and MACs - requires special drivers and software to load music to the device.

The recommendations on-line are to use Gnomad tool to sync. When the HV02T is plugged in and Gnomad is started, the player is detected.

The second hurdle is that most of Rany's music is in ogg format. Most players only support the MPEG Layer 3 or mp3 format. His files need to be converted mp3. Robert installed the highly rated soundConverter application for Ubuntu. This converted some of Rany's files from OGG Vorbis format to MP3 format. Since these are lossy compressed formats, the quality was somewhat reduced.

Once the music is in the correct format, it is just a matter of having Gnomad upload the files to the player.

Now Randy has music on his player.

CD Burning
David's PC won't burn CDs.

Mint 9, Ubuntu 9.04 using brasero reports there is no CD in the drive. It is an older PC, but his daughter's PC also has issues. cdrecord, the command line burner, has no issues with burning CDs on his system. It is the graphical clients that have issues.

Ubuntu in VirtualBox on Microsoft Windows
Ubuntu 9.10 is installed to a virtual box environment. The desktop is stuck at 800x600. The virtualbox ose guest tools were required to be installed. Then a manual configuration was written. The virtualbox guest tools detected higher resolutions, but the manual configuration of an /etc/X11/xorg.conf file is requires.

Q&A

Q: What is the difference between 'web browser,' a blue button by default on the Ubuntu desktop and firefox?

A: Ubuntu is a Debian Linux derivative for friendly easy access. The web browser is just a re-branded version of firefox of a difference version than you may expect. You can always download another version of firefox and install it if you do not like the version installed.

General Discussion :: RE: 2009 Meeting Minutes

Author: waveclaw
Subject: Linux SIG 12/03/2009
Posted: Fri Dec 04, 2009 2:15 pm (GMT -6)
Topic Replies: 8

Linux SIG 12-03-2009

They changed the keys to the doors. Will have to get new keys.

Demo of a BSD NAS server.
BSD based http://www.freenas.org/ (similar to http://www.openfiler.com/about/ available on Linux)
NFS, SMB disk sharing are the goals.

Eric helped with the setup

1. Turned out he did not have the CIFS/SMB service setup and the directory he was sharing was non-existent.

2. Eric plugged in his laptop using a switch and extra cables. He can see the mount now and should be able to map a drive using the Linux utilities:

ifconfig
- checked his IP address to show that he had an address on his eth0 (first Ethernet card)
-

Code:

smbclient -L <the freenas's ip address>

- the -L list option always takes an IP address. This is unusual in that every other command take a Windows Work group or computer name.
- this returned a list of shares including the disk exported by the NAS above.
- these returned just the work group. The work group is dynamic and
3. Eric attached to the mount and looked at it. smbclient can act like an ftp client and check the exported file system without actually mounting it.

Note that the UNC path has the \ replaced with / because this is on Linux.

Code:

smbclient //freenas/Windows89Setupfiles
smb: \> ls
.
..

smb:\> dir
.
..
smb:\> mkdir w98setup

smb:\> dir

.
..
w98setup

smb:\>

- There's nothing there so no surprised.
- There were password prompts, but this is an anonymous share with not user name restrictions.

5. So, the share is setup correctly.

CD-ROM Support

Eric helps with webmin's setup. There is a cd-rom burner on the system. While you can setup command-line burning, you'd probably need to download and install new tool.

Brasero on Ubuntu 9.04

Couldn't get it to work on two different computers. No error, just nothing happens.

Alternatives like k3b are suggested.

These will likely all use an underlying program to do the work. The errors from these programs are probably not being passed up to the user.

Could bring the PC in next month and look at it. Might be a smiple as permissions or being in the cdrom group. Might be as complex as an incompatibility with the driver. Two systems implies a configuration issue, however.

VitualBox on Windows running Linux

Ubuntu 9.04 worked. Ubuntu 8.04 kernel panicked. Probably the kernel version. If it were upgraded it might work. Trying to make a virtual image out of an existing system may work. Some virtual hardware from VirtualBox could be incompatible with that version Linux.

Next meeting

Eli's G1 Android phone. It's based on Linux. Eli has also got an emulator that gives you the ability to see the phone on the overhead. And I guess it's good for software development, too.

General Discussion :: RE: 2009 Meeting Minutes

Author: waveclaw
Subject: Linux SIG 10-01-2009
Posted: Wed Oct 07, 2009 8:56 pm (GMT -6)
Topic Replies: 8

Linux SIG 10-01-2009

Eric discusses basic Linux with Xubuntu. The Palm Pre Linux environment will be the advanced topic.

Introductory Topic: Q & A Xubuntu Demo

Q: Can I put an icon on my desktop?

A: Yes, as shown in the demo you can drag and drop files onto most Linux desktops and an icon will appear there just like in Windows or on the Mac.

Q: How can I make a new file, like to make an empty document to fill in later?

A: Several ways: right click on the desktop and a menu will pop up. You can create "folders" called directories and empty files from options in that menu.

Most Linux desktops such as GNOME and KDE have a 'home' folder showing on the desktop. Clicking on it opens a file manager window showing your home directory. Right clicking in this window will also bring up a menu to create files and folders.

Q: Is there a 'My Documents' folder for Linux?

A: Many Linux desktops will create a folder called 'Documents' or 'My Documents' the first time you log in.

You can create a 'My Documents' folder in the above ways as mentioned for new folders and files.

If you save files there Open Office and other that programs may remember the last place you saved documents will save things there if no new place is given. However, the first time you save a document you may need to use the file menu, save as submenu and look for the correct folder in the window that pops up.

You can set the default location for saved files in Open Office. Open the Tools menu, click Options and a window will pop up. In this window select Paths. There is an entry for 'My Documents.' Setting this to a folder (aka directory) will change where all the open office programs will save new documents by default.

In general, right clicking things in a Linux desktop like GNOME or KDE will do what you expect if you are familiar with Windows or Mac.

Q: What do you recommend for playing music on a Linux desktop?

A: Both rythmbox (http://www.gnome.org/projects/rhythmbox/) and xmms (http://www.xmms.org/)are very good, lightweight music players. xmms closely resembles the popular winamp music player from Windows. Rythmbox claims to be inspired by Apple's itunes.

People with very large music collections have had issues with fat multimedia clients like GNOME's banshee and KDE's Amarok. These two are simple clients for just playing music. They support any kind of music that the gstreamer system can.

Q: Can I play mp3s and other types of audio files on my Linux box?

A: Yes, http://www.fluendo.com/ sells the mulimedia codecs for, as of this writing, 28 Euros (~$40.76 via google.com) The do have home free codes for playing mp3s. The free codes are available in the Ubuntu repositories. Fluendo supports openSolaris, Ubuntu, SuSE, fedora, Mandriva and many more platforms with packaged downloads for those systems.

All are ready to install. The codecs are provided in the form of gstreamer plug-ins (just shared libraries.) This means the fluendo codecs can enable applications like rythmbox and xmms to play commercial encoded music like mp3s.

Advanced Topic: Palm Pre

This is a smart phone - a cellphone with PDA, web browser and other features. This is also a Linux box. The default hostname is 'castle.'

The Pre features a multi-touch on a decently rugged screen. 2x VGA which is aware of it's orientation and will change portrait to landscape as needed. There is a slide-out keyboard.

Very iPhone-like but uses a search metaphor for the default user interfaces. Searching for the Konami code brings up the option to enable developer more and tether to a USB-enabled PC as a networked device.

The Linux system has an ipkg package managers like the dd-wrt Linux router software. There are ssh and other utilities available. With the proper software the phone makes for a decent emergency wifi hotspot using the owner's cellular data plan. Not youtube streaming and LAN gaming speeds, but certainly basic web browsing and remote terminal access.

With a bluetooth keyboard and mouse, this becomes a netbook which fits in you pocket.

Popular sites for Palm Pre homebrew applications are http://www.precentral.net/ and http://www.palmprehomebrew.com/

Future Topic Idea: Compare the Pre with a Google Android Phone.

General Discussion :: RE: 2009 Meeting Minutes

Author: waveclaw
Subject: Linux SIG 08-06-2009
Posted: Thu Aug 06, 2009 6:25 pm (GMT -6)
Topic Replies: 8

Linux SIG 08-06-2009

Linux Install-fest / Problem night.

Install-fest where nobody installed anything. People came with existing systems.

Ubuntu printer repair

Per month before last, Lynn is needing help sharing his printer. The files are sharing fine. Root cause was the Kapersky Firewall blocking printing.

Firewalls are great for protecting your PC from others' actions but not your own. Also, they are designed to block services by nature. Firewalls on your desktop are excellent for when people get past your firewalls on the network access points or routers that you may have installed to connect all your PCs together. A desktop firewall is best used if people are going to be adding and removing machines from your network. Keeping your patches up to date and not visiting bad sites will cover most issues.

LinxuxSIG Wireless Network

Charlie is helping Chris with his wireless support. Chris has an intel chipset with dual wimax and wifi and earliest kernel that supports is is 2.6.30. So they are trying and experimental ubutntu 2.6.30. The kernel is being copied via a usb drive.

Some of the regulars are running netbooks tonight.

TV Capture Cards

Robert has a hauppauge that he is planning on using for a PVR. hauppauge TV capture cards are supported quite well under linux with a binary driver. They are PCI or PCI-X cards. PVR specific drivers; http://pvr.sourceforge.net/. Also see http://www.mythtv.org/. Note that the HD quality cards are sold to OEMs only and must be provided to customers in closed boxes. (Yay DRM.) There are HDMI cards, but they usually only have Mac / Windows drivers. The cost for the Mac to support the HDMI are around $25,000 for the $500-600 card. This is obviously targeted at TV studios. Just minimal performance requirements for the bit-rate is a $4,000 system.

Best Cross-platform Cards
usb - pretty standard, very good support for all three standards
tv capture card - see above
network card - 99% of the cards in PCI, ISA, PCI-X are supported
graphics cards - some require binary drives. Recent add-in cards might not have drivers. Older cards will have F/OSS drivers and might now be not as well supported.

Version Numbering

Some discussion about the fun of version numbers: http://www.codinghorror.com/blog/archives/000793.html and http://en.wikipedia.org/wiki/Software_versioning.

Redhat has long-term support versions:
3 is being end-of-lifed soon
4.7 is current
5.3 is newest
5.7 with KVM (kernel virtualization module) to be released soon

Scientific Linux, whitebox and CentOS are popular versions based on logo-free recompiles. Several people, Roboert included have moved to CentOS for their systems.

Ubuntu 8.04 was released April 2008. 9.04 was released April 2009. 10.4 is expected in April 2010. The numbers follow the date of release.

Debian uses character named from Toystory for versions: Potato, Woody, Sarge. The Testing version is Lenny. The unstable version is called Sid.

Printing Support

Check linuxprinters.org first! If you have a printer that you want to use, go to the site and check it out.

Postscript supporting printers work as a rule. PCL 4 and 5 printers should work if the drivers are available.

Printing in Linux uses CUPS as mentioned many times in the last few month.

Next month

Eric will be taking over. Probably return to the dual topic format: beginner and advanced topics. Robert will return to teaching his Intro to Linux class for the college.

General Discussion :: RE: 2009 Meeting Minutes

Author: waveclaw
Subject: Linux SIG 06/04/2009
Posted: Thu Jun 04, 2009 7:58 pm (GMT -6)
Topic Replies: 8

Linux SIG 06-04-2009

Projects and Problems

Several people, some old faces not seen in a while.

Problems

#1 - Sound Support HP 1035RN
http://www.hp.com/united-states/campaigns/mini1000/alt.html

Customer's preferred solution: wait. HP's release of Linux for the netbook claims to be good for playing music, but doesn't quite support all the hardware at the moment. So the HP's owner is installing 'Dennis' - the official mini-Ubuntu for these mini-PCs (see http://luigik4ch0.blogspot.com/2009/04/how-to-run-hp-mi-edition-from-usb-flash.html.)

#2 - Media Player crashes. Samba: I have a media computer and a bunch of mp3 files shared out via samba. The windows machines can steam from this. The linux boxes can't: Amarok, etc all crash trying to play the files from the share. It's on a gigabyte Ethernet network. The applications die complaining that they cannot access the files. Sabyon (Gentoo KDE) version of Linux. I can copy the files locally and use them fine. I can navigate to the files using either the Konquorer file manager or the application dialogs.

Is this using fuse to mount it? Permissions issues? Can try to use NFS shares? You will need to force your desktop to mount it. Konquorer is using it's internal support for the files, likewise when it is being invoked as the dialog used by the application. You can add it to the fstab or manually do so. A quick google search should show you how.

#3 - Printing over the network from Linux.

I can print to my printer if I hook my printer up to my Linux laptop. But at home, with the printer shared via the Microsoft XP Pro desktop, I cannot reach that from my Linux laptop.

Code:

(Internet)
|
+------------+ +---------+
| router | | Printer |
+------------+ +---------+
| | | |
| | | +----------------+
| | +-------| XP Pro Desktop |
+--------------+ | | +----------------+
| Linux Laptop |-+ +-----------------+
+--------------+ | XP Media Laptop |
+-----------------+

Recommendation: ask the router company about the security settings. Also check the security setting on the XP Pro desktop.

#4 - Two wire modem. Using an Ubuntu Linux at home. What do I have to do to put a Linksys router behind it?

Couple of ways:

bridging - login to the 2-wire modem. Use the 'dumb bridge' mode. This will cause the IP address normally given to the modem to be given to the router.

normal - setup the Linksys router and the PC behind the modem. PPPoE will need to be setup on the Linksys.

User name for the modem is usually 'admin'. The password is the on MAC label on the modem. (Usually on the underside of the modem's case.)

The modem usually lives at 192.168.1.254 or 192.168.0.1 and you can access that from your PC to setup either bridging or use the normal settings.

If none of these addresses work, you can check what it will be by looking for the default gateway while you are connected to the two-wire modem. Open a terminal window and type 'netstat'

Code:

netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
192.168.2.1 0.0.0.0 255.255.255.255 UH 0 0 0 wlan0
0.0.0.0 192.168.2.1 0.0.0.0 UG 0 0 0 wlan0

#5 - Install a KDE app with Database dependencies. Multiple times we've tried to install krecipes. But it keeps crashing. Can we see an installation of krecipes?

From the krecipes site, you need to have one of the three supported database: postgresql, mysql or sqlite. Note that it will still crash on you. It's got "issues".

#6 - Web browser performance. 3Ghz CPU with 2Gb of ram. How many firefox tabs can I have open?

A lot. Note that with a lot of flash is will kill your system with load. Older Firefox versions have bad memory leaks and would run out of memory if left running for long amounts of time. Firefox can be very finicky while it loads and renders pages.

Miscellaneous Topics

At this point people broke up into small groups for individual help.

General Discussion :: RE: 2009 Meeting Minutes

Author: waveclaw
Subject: LinuxSIG 05/07/2009
Posted: Thu May 07, 2009 5:38 pm (GMT -6)
Topic Replies: 8

LinuxSIG 2009-05-07

Intro Topic:Q/A

Q: What is bonding?

A: You can combine multiple network interfaces (multiple cards, etc) into one fake interface. This fake interface runs at multiples of the speeds of each individual and is resistant to an individual cable being removed.

This is popular with small LANs where people are moving huge amounts of data like video data editing offices.

Q: Can the backplane in a PC support gigabit speeds?

Older systems cannot. Newer systems with PCI-X can support it with NICs in the PIC-X slots.

Some intel systems used special bypass logic to support gigabit speeds.

Newer PC systems usually have support for full gigabit speeds using the built-in card.

Note: 10 gigabit ethernet is available, but you won't be seeing that in a home anytime soon.

Q: What is a step up from iSCSI?

A: For multiple people sharing, NFS and samba (CIFS) can be used with greater security. Samba supports Microsoft Windows NT encryption of passwords, network traffic and kerboros security features.

Advanced Topic: iSCSI

Not a file sharing protocol like samba or nfs. It is a way to pipe SCSI commands over a network. The low level commands normally used on your computer sent over the network. You can format the device like an internal harddrive. Only one host can use the disk at one time.

Initiators: the client that connects to the iSCSI host.
Target: the server that has the physcial disk.

Typical use is to have a large disk array in the same location as a very large (in CPU terms) server. The server uses the disk array to increase its storage over time.

Popular with SANs - Storage Area Network world.

Popular with NAS - Network Attached Storage.

The popular implementation under linux is Open iSCSI. Redhat, Ubuntu support it. CentOS has support for it.

There is a mini-linux distribution that specializes in this.

This is not restricted to SCSI hardware, it just produces a 'SCSI' virtual disk (the target) to attach to over the network.

Note that under Ubuntu 8.04 and greater, every drive shows up as a SCSI disk anyway: MRLL, IDE, EIDE, FC, etc.

Step 1: start the target server on the, well, target server:

Code:

tgtd

Step 2: view the current configuration

Code:

tgtadm --lld iscsi --op show --mode target

Step 3: Setup the storage

You are actually setup a 'controller' and 'devices' for the controller to use.

Code:

tgtadm --lld iscsi --op new --mode target --tid 1 -T qualified_name

where qualified_name is a unique string that Identified the storage array:

Code:

<some id>.year-month.<revesed dns name>:<anything>

for example

Code:

iqn.2007-05.com.example:storage.disk1.mystuff.sys1.abc

Step 4: Check the configuration you just made

Code:

tgtadm --lld iscsi --op show --mode target

get back information about the controller and show now storage attached to it (e.g. No Backing Store)

Step 5: add some stroage

In the example, using /dev/sdb on the system called 'target'

Code:

tgtadm --lld iscsi --op new --mode logicalunit --tid 1 --lun 1 -b

LUN: Logical Unit Number, the SCSI number associated with the bus.

Note that on iSCSI, Fiber Channel (FC), etc the old narrow-scsi limit of 7 LUNs is discarded. Some people have reported serial SCSI chains with 100s of devices on them.

Step 6: tell the target to listen for connection

In the example, we are just listening on all interfaces for everyone.

Code:

tgtadm --lld iscsi --op bind --mode target --tid 1 -I ALL

Step 7: start the 'iscsi' service on the client, the initiator

Code:

/etc/init.d/iscsi start

Step 8: discover the available targets on the target server

Code:

isciadm -m discover -t sendtargets -p <address of the target box>
/etc/init.d/iscsi restart

Note: sometimes the iscsi client will hang instead of shutdown. You may have to force it to quit.

Step 9: check the disks you see

Code:

fdisk -l

(shows all the disks on your system, including the new iSCSI one with now valid parition)

Step 10: write a partition to the disk

Code:

fdisk /dev/sda

Step 11: write a filesystem to the new disk

Code:

mkfs -t ext3 /dev/sda1

Step 12: use to your heart's content

Code:

mount /dev/sda1 /mnt

ANYTHING you could normally do to a drive you can do locally with this iSCSI disk.

There is an initiator available for Microsoft Windows (XP/2000/2003 Server editions) that can used the drives. You could have Windows clients that use a Linux server which is outputting targets.

Remember, this is a drive only usable by one client at a time. It is a good practice to not mount the drives on the target when they are being shared out. However you can still use tools like SMART to monitor the health of the drives being shared out.

iSCSI supports security modes that can be used to protect your files with password protection, etc. Raw iSCSI is not encrypted, so the traffic can be sniffed. Performance over a non-dedicated network is very low. Over the public Internet through a VPN would be worse.

You can setup a network such that users whose data must be backed up are forced to keep their files somewhere private yet able to survive the death of their client.

General Discussion :: Home Control with Linux

Author: robertngreen
Subject: Home Control with Linux
Posted: Mon Apr 06, 2009 12:17 pm (GMT -6)
Topic Replies: 0

Here is the link I was looking for. It has more than just home heat and air control.

http://www.linuxha.com/

This site has a little bit of everything for home automation.

General Discussion :: RE: 2009 Meeting Minutes

Author: waveclaw
Subject: LinuxSIG 04/02/2009
Posted: Thu Apr 02, 2009 6:30 pm (GMT -6)
Topic Replies: 8

LinuxSIG 04/02/2009

RAID

Redundant
Array of
Inexpensive
Disks

Combine a bunch of real physical disks into one virtual disk.

RAID 0 - striping. Take two drives, split the data between the drives. Increases speed if done correct. If ether drive dies, whole 'disk' goes away. Doubles your space. Needs 2 drives or sets of even pairs of drive.

RAID 1 - mirroring. First proper RAID array. Each drive gets a full copy of the data. Can survive 1 failure at the cost of wasiting 50% of your space.

RAID 10 - RAID 1+0 or 0+1. Making a RAID array of another array. mirroring stripped disks or stripping mirrored disks. Faster, survives 1

RAID 2 - Rarely used.

RAID 3 - Rarely used.

RAID 4 - 2 drives plus a parity drive. Similar to Raid 0, but can survive loss of either the parity drive or one of the stripped drive. Resultant disk is size of 2 drives.

RAID 5 - interleaves parity information with the data. Takes at least 3 drives. Increases size of resultant disk.

Support

Hardware supported RAID if often motherboard 0 or 1. Special cards can do fast I/O and support up to RAID5. Often needs special drivers.

Since Windows 2003 Microsoft OSes can do RAID5 in software. Linux has supported raw RAID for quite some time and can make an array out of any block device.

To demo today, Robert will be creating a Linux RAID5 of 2Gb flash drives.

1. Robert plugs in the USB drives. They show up as normal disks.

2. They do need to be reformatted with new partitions created. Each drive needs to have a partition of type 'fd' for Linux raid autodetect.

Code:

okc-powellj-01:/home/powellj/bin # fdisk /dev/sda

Command (m for help): p

Disk /dev/sdb: 6000 MB, 6000132096 bytes
255 heads, 63 sectors/track, 729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x0008ad0c

Device Boot Start End Blocks Id System
/dev/sda1 1 729 5855661 fd Linux raid autodetect

In many cases you will create the RAID array when you install Linux. In this case, Robert is creating a new array with a 4th spare drive. When a drive fails in this array, the hot spare will be formatted to restore the virtual drive.

mdadm is the Linux RAID array tool:

Code:

mdadm --help -C
Usage: mdadm --create device -chunk=X --level=Y --raid-devices=Z devices

This usage will initialise a new md array, associate some
devices with it, and activate the array. In order to create an
array with some devices missing, use the special word 'missing' in
place of the relevant device name.

The things we care about are --level, to tell the level, and --raid-devices to tell the number of devices we want in the array.

3. Robert Creates the array

Code:

mdadm --create /dev/md0 --level=5 --raid-devices=3 --spare-devices=1 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1
(some warnings about filesystems present)
(asks you to Continue the array creation._

4. You can check the results of the create using the /proc/mdstat file.

Code:

cat /proc/mdstat
Personalities : [linear] [raid6] [raid5] [raid4]
md0 : active raid5 sdc1[4] sdd1[3](S) sdb1[1] sda1[0]
3904768 blocks level 5, 64k chunk, algorithm 2 [3/2] [UU_]
[======= >............] recover = 50.6% (990120/1952384) finish=2.8min speed5561K/sec

USB is a serial bus. There are no switches, just hubs and everyone shares them. Building a RAID off a single USB hub is slow and rather painful. Also, USB is based on the PC polling the devices on the end of the bus. This guarantees wakeup of devices and high use of the bus.

Code:

cat /proc/mdstat
Personalities : [linear] [raid6] [raid5] [raid4]
md0 : active raid5 sdc1[4] sdd1[3](S) sdb1[1] sda1[0]
3904768 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]

unused devices: <none>

5. Once complete you can work with your new virtual disk, or Meta Device, /dev/md0.

Code:

mkfs -t ext3 /dev/md0
....

Note: the software RAID documentation at the Linux Documentation Project, lpd.org, is out of date. You can google better results.

The results? 3.7G virtual disk.

Code:

mount /dev/md0 /mnt
ls /mnt
lost+found

The working capacity of a RAID5 is minus about 1 drive of space on top of idle spare drives for hot swaping.

Robert goes to fail some disks. Linux can simulate failure and force a device out of the array:

Code:

mdadm --manage /dev/md0 --fail /dev/sdb1

Personalities : [linear] [raid6] [raid5] [raid4]
md0 : active raid5 sdc1[4] sdd1[3] sdb1[1](F) sda1[0]
3904768 blocks level 5, 64k chunk, algorithm 2 [3/2] [U_U]
[======= >............] recovert = 50.6% (990120/1952384) finish=2.8min speed=5561K/sec

Be aware that with USB drives, the devfs system may not like continual removal and addition of disks using failure.

Also, note that the filesystem (mounted at /mnt) was never unmounted during this and the /mnt filesysetm is still available.

Robert now removes the failed disk. Marking the disk failed will result in it still being part of the array. To remote the disk without confusing the array, it is best to remote the disk. The confusion occurs because any replacement drive may be added and end up at another location (e.g. USB /dev/sde instead of /dev/sdc in the demo)

Code:

mdadm --manage /dev/md0 --remove /dev/sdb1
mdamd: hot removed /dev/sdb1
cat /proc/mdstat
Personalities : [linear] [raid6] [raid5] [raid4]
md0 : active raid5 sdc1[4] sdd1[3] sda1[0]
3904768 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]

unused devices: <none>

Note that Linux supports a lot of hardware RAID cards. Usually special tools needed will be provided by the vendor. Sometimes special RAID card software will be provided, including drives, by the vendor. Setup of a hardware array normally occurs in the RAID card's BIOS but follows the same process.

Trivia

[Open Apple] + [F5] turns on text-to-speech

Possible followup topic: iSCSI over ethernet

Q&A

Q: JBOD vs BIG?
A: JBOD is Just a Bunch of Disks.

Q; VMware on Linux?
A: There is a control panel applet that can be run to manage the VMware instances. Several Windows systems are kept in VMware at DaVinici for certain applications.

Q: Minimal memory for Ubuntu 8.04?
A: 512mb probably a safe bet. 256mb is possible (xubuntu) but applcation selection is limited. Memory is cheap enough for DDR2 or DDR3 that purchasing more should not be an issue.

Q: Support 8.04?
A: It is long-term support, so 5 years from release.

General Discussion :: RE: 2009 Meeting Minutes

Author: waveclaw
Subject: Linux SIG 2009-03-05
Posted: Thu Mar 05, 2009 7:20 pm (GMT -6)
Topic Replies: 8

LinuxSIG 2009-03-05

Robert presents the Jack audio subsystem and Mediabuntu.

Intro Topic: Mediabuntu

http://www.medibuntu.org/

Geared towards audio, video and photo users. It's a standard Ubuntu (8.10 in the demo) with installer, repositories and software toward audi, video and 3d rendering applications.

The installer asks what you want to do: video editing or photohopping or audio production.

He needed to tune an audio system to the room it was in. The better audio people can do this by ear using sample sounds. He needs to use a frequency spectrum analysis of the sounds. Initial work failed to get anything running due to pulseaudio. Pluseaudio is much like eSound Daemon, including the horrible bugs when it was originally introduced.

Mediabuntu includes Jack. Much like pulseaudio, but more mature, it is a professional low-latency patchbay system. You take different hardware and software and connect them together via Jack.

Jack Audio Subsystem

Jack is a daemon. It is a process that connects everything together. However you must start the daemon. Mediabuntu does not this daemon automatically.

JACKcontrol - the Jack Audio Connection Kit - sets up the bay of 'patches' you can patch together. (Note that a lot of media people seem to like to work in the dark. The default UIs seem to favor this.) The connect button pops up the things you can connect from and connect to. At the start you will have nothing but your physical devices.

He uses a program called jaaa to do the analysis. jaaa is the JACK Alsa Audio Analyzer. It requires that you patch in an input. Running jaa adds it to the input and output screens in the connection user interface as described above. If you play with the options with JACK on a system running pulseaudio, you may lose the applications when the changes are propigated by killing or restarting your audio applications.

http://www.flickr.com/photos/26350467@N05/3337451226/

jaa with the noise floor from the room.

Using a tool called freqtweak, he connects the output of jaa into the input on freqtweak. The output of the system is then plugged via the patch bay into the output of freqtweak. He got the robotic sound to come out of the speakers on the walls of the room.

http://www.flickr.com/photos/26350467@N05/3337451230/

The power of JACK is thus the ability to run an application and dynamically throw the application into a chain of applications editing your audio.

* beat senquencers
* track managers
* audio players, converters,
* editors

Q&A

Q: Can I use this for a mediaPC?

A: This is for media creators and not mediaPC type setups. There are some geared toward is like mythbuntu or a normal ubuntu install with boxi insalled.

Q: Is there some application that will rename my many mp3s and music files at the directory level?

A: easyTAG at http://easytag.sourceforge.net

Q: Bluetooth or other wireless hardware support?

A: Actually many people have found that they can attach or associate bluetooth hardware and it will just work. Depends on the chipset from the manufacturer. He has had very good luck with netgear, zonet and usb based adapters (since they usually use the same or similar USB chipsets to do things like create a usb brigde.)

See http://linux-wless.passys.nl.

You can search via interface, chipset, manufacturer and several other criteria for support under Linux.

Q: Is there any advantage to the normal user using tomato or dd-wrt or openWRT on your wireless router?

A: Maybe. For VoIP applications, skype et al., you want better QoS support and these custom Linuxes. bitorrent clients and webservers are available to use. However, for the normal user the default firmware is preferred and changing that may violate your warranty.

Q: Can you get white noise from cat /dev/random > /dev/audio?

A: No. The sound from that is truely random or 'pink' noise. White noise is all even across the whole spectrum, much like white light.