LinuxMCE - User contributions [en]

Create RAID in LMCE

2008-08-16T03:28:12Z

Rdmustang: /* Troubleshooting */

== Introduction ==
RAID (Redundant Array of Independent Drives) refers to a data storage scheme which has as a benefit increase of the data integrity, fault-tolerance, throughput and/or capacity
There are 3 standard RAID levels which can be used in LMCE, to define RAIDS:
=== RAID 0 ===
* Striped Set (2 disk minimum) without parity
* provides improved performance
* additional storage
* no fault tolerance from disk errors or disk failure. Any disk failure destroys the array, which becomes more likely with more disks in the array
=== RAID 1 ===
* Mirrored Set (2 disks minimum) without parity.
* Provides fault tolerance from disk errors and single disk failure.
* Increased read performance occurs when using a multi-threaded operating system that supports split seeks, very small performance reduction when writing.
* A drive has its data duplicated on another different drive. If either drive fails, the other continues to function as a single drive until the failed drive is replaced.
Conceptually simple, RAID 1 is popular for those who require fault tolerance and don't need top-notch read performance.
=== RAID 5 ===
* Striped Set (3 disk minimum) with Distributed Parity
* Distributed parity requires all but one drive to be present to operate
* drive failure requires replacement, but the array is not destroyed by a single drive failure.
* Upon drive failure, any subsequent reads can be calculated from the distributed parity such that the drive failure is masked from the end user.
* The array will have data loss in the event of a second drive failure and is vulnerable until the data that was on the failed drive is rebuilt onto a replacement drive
== Creating RAID ==
# Go to LMCE's admin web page at Advanced->Configuration->RAID section.
## Specify the computer that should hold the RAID in the Parent section.
## Give a Description to the Raid you’re creating.
## Choose the type of RAID, according to what you need to do.
## Check the Use automatically box, if you want your data to be stored automatically using this RAID.
## Choose what kind of data structure you want for this RAID. Then click on the Add button to save your settings.
# Choose the disk drives you want to include in the RAID, by selecting the available ones from the drive list. The list contains only the disks that there are not used. Also you have the option to add spare disks.
# When you have finished adding your disks, press the ‘Create RAID array’ button, to re-write your data in the desired pattern. You will see your RAID created in the list and you will be able to access the advanced configuration page, to add new drives, or to delete it.
Note: This is a totally software RAID, you don’t need to activate the RAID in your BIOS.
[[Category: Tutorials]][[Category: Storage]]
== Troubleshooting ==
#If the array keeps coming back as failed, try stopping non-existant RAID devices:
## sudo mdadm --stop /dev/md0
## sudo mdadm --stop /dev/md1
#If you continue having problems then try ssh'ing in, delete any partitions using fdisk, reboot and try again.

Create RAID in LMCE

2008-08-16T03:27:36Z

Rdmustang: /* Troubleshooting */

== Introduction ==
RAID (Redundant Array of Independent Drives) refers to a data storage scheme which has as a benefit increase of the data integrity, fault-tolerance, throughput and/or capacity
There are 3 standard RAID levels which can be used in LMCE, to define RAIDS:
=== RAID 0 ===
* Striped Set (2 disk minimum) without parity
* provides improved performance
* additional storage
* no fault tolerance from disk errors or disk failure. Any disk failure destroys the array, which becomes more likely with more disks in the array
=== RAID 1 ===
* Mirrored Set (2 disks minimum) without parity.
* Provides fault tolerance from disk errors and single disk failure.
* Increased read performance occurs when using a multi-threaded operating system that supports split seeks, very small performance reduction when writing.
* A drive has its data duplicated on another different drive. If either drive fails, the other continues to function as a single drive until the failed drive is replaced.
Conceptually simple, RAID 1 is popular for those who require fault tolerance and don't need top-notch read performance.
=== RAID 5 ===
* Striped Set (3 disk minimum) with Distributed Parity
* Distributed parity requires all but one drive to be present to operate
* drive failure requires replacement, but the array is not destroyed by a single drive failure.
* Upon drive failure, any subsequent reads can be calculated from the distributed parity such that the drive failure is masked from the end user.
* The array will have data loss in the event of a second drive failure and is vulnerable until the data that was on the failed drive is rebuilt onto a replacement drive
== Creating RAID ==
# Go to LMCE's admin web page at Advanced->Configuration->RAID section.
## Specify the computer that should hold the RAID in the Parent section.
## Give a Description to the Raid you’re creating.
## Choose the type of RAID, according to what you need to do.
## Check the Use automatically box, if you want your data to be stored automatically using this RAID.
## Choose what kind of data structure you want for this RAID. Then click on the Add button to save your settings.
# Choose the disk drives you want to include in the RAID, by selecting the available ones from the drive list. The list contains only the disks that there are not used. Also you have the option to add spare disks.
# When you have finished adding your disks, press the ‘Create RAID array’ button, to re-write your data in the desired pattern. You will see your RAID created in the list and you will be able to access the advanced configuration page, to add new drives, or to delete it.
Note: This is a totally software RAID, you don’t need to activate the RAID in your BIOS.
[[Category: Tutorials]][[Category: Storage]]
== Troubleshooting ==
#If the array keeps coming back as failed, try stopping non-existant RAID devices:
## sudo mdadm --stop /dev/md0
## sudo mdadm --stop /dev/md1
#You may also have to ssh in and delete any existing partitions manually using fdisk.

Create RAID in LMCE

2008-08-16T03:27:17Z

Rdmustang: /* Troubleshooting */

== Introduction ==
RAID (Redundant Array of Independent Drives) refers to a data storage scheme which has as a benefit increase of the data integrity, fault-tolerance, throughput and/or capacity
There are 3 standard RAID levels which can be used in LMCE, to define RAIDS:
=== RAID 0 ===
* Striped Set (2 disk minimum) without parity
* provides improved performance
* additional storage
* no fault tolerance from disk errors or disk failure. Any disk failure destroys the array, which becomes more likely with more disks in the array
=== RAID 1 ===
* Mirrored Set (2 disks minimum) without parity.
* Provides fault tolerance from disk errors and single disk failure.
* Increased read performance occurs when using a multi-threaded operating system that supports split seeks, very small performance reduction when writing.
* A drive has its data duplicated on another different drive. If either drive fails, the other continues to function as a single drive until the failed drive is replaced.
Conceptually simple, RAID 1 is popular for those who require fault tolerance and don't need top-notch read performance.
=== RAID 5 ===
* Striped Set (3 disk minimum) with Distributed Parity
* Distributed parity requires all but one drive to be present to operate
* drive failure requires replacement, but the array is not destroyed by a single drive failure.
* Upon drive failure, any subsequent reads can be calculated from the distributed parity such that the drive failure is masked from the end user.
* The array will have data loss in the event of a second drive failure and is vulnerable until the data that was on the failed drive is rebuilt onto a replacement drive
== Creating RAID ==
# Go to LMCE's admin web page at Advanced->Configuration->RAID section.
## Specify the computer that should hold the RAID in the Parent section.
## Give a Description to the Raid you’re creating.
## Choose the type of RAID, according to what you need to do.
## Check the Use automatically box, if you want your data to be stored automatically using this RAID.
## Choose what kind of data structure you want for this RAID. Then click on the Add button to save your settings.
# Choose the disk drives you want to include in the RAID, by selecting the available ones from the drive list. The list contains only the disks that there are not used. Also you have the option to add spare disks.
# When you have finished adding your disks, press the ‘Create RAID array’ button, to re-write your data in the desired pattern. You will see your RAID created in the list and you will be able to access the advanced configuration page, to add new drives, or to delete it.
Note: This is a totally software RAID, you don’t need to activate the RAID in your BIOS.
[[Category: Tutorials]][[Category: Storage]]
== Troubleshooting ==
If the array keeps coming back as failed, try stopping non-existant RAID devices:
# sudo mdadm --stop /dev/md0
# sudo mdadm --stop /dev/md1
You may also have to ssh in and delete any existing partitions manually using fdisk.

Create RAID in LMCE

2008-08-16T03:26:41Z

Rdmustang: /* Creating RAID */

== Introduction ==
RAID (Redundant Array of Independent Drives) refers to a data storage scheme which has as a benefit increase of the data integrity, fault-tolerance, throughput and/or capacity
There are 3 standard RAID levels which can be used in LMCE, to define RAIDS:
=== RAID 0 ===
* Striped Set (2 disk minimum) without parity
* provides improved performance
* additional storage
* no fault tolerance from disk errors or disk failure. Any disk failure destroys the array, which becomes more likely with more disks in the array
=== RAID 1 ===
* Mirrored Set (2 disks minimum) without parity.
* Provides fault tolerance from disk errors and single disk failure.
* Increased read performance occurs when using a multi-threaded operating system that supports split seeks, very small performance reduction when writing.
* A drive has its data duplicated on another different drive. If either drive fails, the other continues to function as a single drive until the failed drive is replaced.
Conceptually simple, RAID 1 is popular for those who require fault tolerance and don't need top-notch read performance.
=== RAID 5 ===
* Striped Set (3 disk minimum) with Distributed Parity
* Distributed parity requires all but one drive to be present to operate
* drive failure requires replacement, but the array is not destroyed by a single drive failure.
* Upon drive failure, any subsequent reads can be calculated from the distributed parity such that the drive failure is masked from the end user.
* The array will have data loss in the event of a second drive failure and is vulnerable until the data that was on the failed drive is rebuilt onto a replacement drive
== Creating RAID ==
# Go to LMCE's admin web page at Advanced->Configuration->RAID section.
## Specify the computer that should hold the RAID in the Parent section.
## Give a Description to the Raid you’re creating.
## Choose the type of RAID, according to what you need to do.
## Check the Use automatically box, if you want your data to be stored automatically using this RAID.
## Choose what kind of data structure you want for this RAID. Then click on the Add button to save your settings.
# Choose the disk drives you want to include in the RAID, by selecting the available ones from the drive list. The list contains only the disks that there are not used. Also you have the option to add spare disks.
# When you have finished adding your disks, press the ‘Create RAID array’ button, to re-write your data in the desired pattern. You will see your RAID created in the list and you will be able to access the advanced configuration page, to add new drives, or to delete it.
Note: This is a totally software RAID, you don’t need to activate the RAID in your BIOS.
[[Category: Tutorials]][[Category: Storage]]
== Troubleshooting ==
If the array keeps coming back as failed, try stopping non-existant RAID devices:
# sudo mdadm --stop /dev/md0
# sudo mdadm --stop /dev/md1

Automatic diskless boot of media directors

2008-07-05T16:53:19Z

Rdmustang: /* Troubleshooting */

[[Category: Tutorials]]
[[Category: Networking]]
[[Category: Programmer's Guide]]
{| align="right"
| __TOC__
|}
LinuxMCE allows [[media director]]s to be booted over the network. This means that you can boot up thin clients without hard drives, or systems with other operating systems without affecting what is already on the disk.

==How to set it up==
===Enable PXE boot===
This is also known as network boot and can be accessed in your computer's [http://en.wikipedia.org/wiki/BIOS BIOS]. The exact procedure varies depending on your PC. Normally you press F2 or DEL right after turning the PC on to enter the BIOS settings. There is then usually an advanced option to enable this.

===Set the correct boot order===
You are also going to want to set the boot order in the BIOS so the network boot comes first, and your hard drive second. However most BIOS's will make you first enable network boot, save your changes, restart the computer, and then enter the BIOS settings a second time to set the boot order.

===Determine your network card's MAC address===

'''This step is not needed since version 7.04'''

<s>When network boot is working you should see at bootup the PC's mac address, and a messages about trying to contact a DHCP server, or trying to find a network boot image. This will be a new message you didn't see before and it means network boot is active on the PC. It will usually try for about 10 seconds to do a network boot image, and then give up and boot off the hard drive. This is what you want. When you see the message that it is trying to do the network boot, write down the mac address.

You can also get the mac address in Windows by running IPCONFIG command prompt, or in Linux by typing ifconfig as root from a console or a terminal.</s>

===Setup the media director in LinuxMCE===

'''This step is not needed since version 7.04 although the May 7th release of 7.10 appears to require it'''

<s>In LinuxMCE Admin go to '''Wizard > Devices > Media Directors'''. Add the media director if this is a new one, and set the mac address. The mac address should be a series of six 2 character sequences separated by colons, like this: 1A:00:F2:21:23:9F

Click 'update' to save your changes, and then click 'Setup Diskless Media Directors'. Wait for the popup window to finish. If this is a new media director you just added, go to Wizard, Restart and click 'Quick Reload Router' so the Router is aware of this new device.</s>

===Boot up from the network===
Now turn on the PC. You should see that it gets an IP address and boots into the media director software. The first time you boot it, it can take up to 30 minutes to boot because it will be installing a lot of the software on the diskless image on the core.

After some time, you will see the avwizard screen where you can choose your UI, resolution and so forth. After finishing the avwizard, the system will setup your interface and eventually you will be prompted by the setup wizard where you should choose the media center setup and then go through your typical setup for this new MD.

==How to use it==
If this media director has a hard drive in it that contains another operating system (like Windows or Linux), then from the media director's on-screen orbiter, or from any other orbiter that is currently controlling that media director, hit the 'power' button and choose 'restart as windows/linux' to boot up the computer off the hard drive and use it like a normal PC. Then choose 'restart as LinuxMCE' from the orbiter to boot it back again into LinuxMCE.

==Troubleshooting==
===PXE-Boot hangs up, looping......===

I have an Asus A7N8X-deluxe board, with two NICs onboard. When I connect one of them the MD tries to boot via PXE. Everything seems to go its way until the line: filename tftpboot/pxelinux.0 comes up, for about 20 seconds and after this.
After this, the last block written:

IP-Config eth0 complete (from 192.168.1.23)
adr: 192.168.80.255 broadcast: 192.168.80.255 netmask: 255.255.255.0
gateway: 192.168.80.1 dns0: 192.168.80.1 dns1: 0.0.0.0
rootserver: 192.168.80.1 rootpath: filename tftpboot/pxelinux.0

is repeated about hours in a really fast way.....

====Answer====
It is switching NICs during the PXE boot. Disable one of the on-board NICs.

:''Source: http://forum.linuxmce.org/index.php?topic=3521.0''

===Diskless Setup Failed===

I have multiple MDs which all give a Diskless Setup Failed after announcing themselves to the CORE.

====Answer====
Log into the Web Interface on the CORE, change to the devices view and open up the options for the new MD. Under Device Data check to make sure that the field Architecture is correct. On mine it shows amd64 but all my MDs are actually Intel chipsets. I manually enter i386 and hit save. Then reboot the MD and it will finish setting itself up correctly.

NOTE: The field labeled Model is not user editable. If you change the Architecture field, upon reboot the CORE will automatically update the Model field appropriately so do not worry about it being wrong.

==GRUB PXE network boot==
In some situations, it may be more appropriate to use GNU GRUB bootloader:

#The machine does not support PXE booting directly (no boot-ROM).
#You can use a GRUB boot menu to decide wheter you want to boot LMCE or the native OS.
#Booting is a lot faster when you boot the native OS by skipping the network step.
#GRUB allows for easy adjustments of the boot parameters at boot-time.

This is described in detail at [[GRUB PXE network boot]].

== Reduce boot time ==
When using diskless boot, all data have to be read over the network connection. This can cause boot up times longer than desirable. To avoid long boot up times, you can tune the NFS mount options of the NFS root. Specifically, the rsize and wsize options. You might do a Internet search for resources on this.
Another option is to implement suspending of the media director. Also know as standby, suspend or hibernate. This function is not integrated into LinuxMCE (yet), and requires some Linux shell hacking. See the [[Suspend]] article for more information.

==Programmer's guide==
The network boot images are contained in /usr/pluto/diskless/[deviceID]. If a network image is corrupted, just delete that directory, and re-run 'Setup Diskless Media Directors'.

When the user hits the power button to change which device is booted, the command is sent to "General Info Plugin", which updates /tftpboot/pxelinux.cfg/01-[mac address]. That file contains a line KERNEL or LOCALBOOT 0, depending on what the user wants to boot. If it's LOCALBOOT 0, then when the media director tries to do a network boot the Core will tell it to boot off the hard drive instead. General Info Plugin then sends the App Server running on that machine a command to reboot.

Since there is both a Linux and Windows version of App Server, if App Server is installed and running on the Windows PC, then LinuxMCE can still reboot it remotely back into the network boot even if it's running Windows. Also the Windows App Server utility gives you a tray icon to switch back to network boot.

==Other Network Cards==
If you get to the remote machine starting the boot process, but then fails with it unable to find eth0, the reason may be because the stock diskless image did not have your network card statically compiled. The linux image building process does allow for additional network modules to be loaded during the boot process. The installer that linuxmce uses builds this image from a base copy of the operating system (ubuntu) that is untar'd during the diskless setup process. It puts this into it's own directory that serves as a virtual harddrive for your diskless machine. In the /usr/pluto/diskless directory you should have a list of device numbers that correspond to your diskless machines. For example: '45' was the number for my diskless machine. Edit the file /usr/pluto/diskless/###/etc/initramfs-tools/modules and add on your nic's module. In my case I edit /usr/pluto/diskless/45/etc/initramfs-tools/modules and added sky2. Then run the /usr/pluto/bin/Diskless_InstallKernel.sh script with the device number (directory name) of your diskless machine. In my case "/usr/pluto/bin/Diskless_InstallKernel.sh 45". This script builds the initrd image and puts it in the proper place (symlinks it actually).

The driver used in my machine was the 'sky2' driver for Marvell Gigabit ethernet cards. Other drivers will be located in the /usr/pluto/diskless/xx/lib/modules/2.xxx/kernel/drivers/net/ directory.