Ubuntu server
From Vertubleu
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General links
http://sebsauvage.net/logiciels/ubuntu_power.html
Desktop sharing
With vino:
sudo vino-preferences
With NX Server (current install): http://doc.ubuntu-fr.org/serveur_nomachine (ou http://www.commentcamarche.net/faq/6687-installer-nx-server)
VirtualBox headless
simple tutorial to get virtualbox running on a headless Linux server:
After install, and to use a graphical interface, some 'guest addition' SW have to be installed on the guest (Virtual Machines). These additions are provided with the virtual box install as a disk image (.iso).
=> Mount this iso to the virtual machine:
Example to mount as a secondary DVD drive (can also be mounted in place of the install DVD):
VBoxManage storageattach "winXP" --storagectl "IDE Controller" --port 1 --device 1 --type dvddrive --medium /usr/share/virtualbox/VBoxGuestAdditions.iso
Then start the virtual machine and install the addition (procedure depends on the guest OS). See detailed instructions in VirtualBox manual - chapter 4).
Additions for Ubuntu 10.04 guest (VM)
If display of mouse does not work properly even afer installing the guest additions, try deleting the /etc/X11/xorg.conf file and restart.
If right Alt key (Alt Gr) does not work: define another key for 3rd level chars here: system/keyboard/layout/options/3rd level. I use the right control key for this purpose (right Alt-Gr works only inconsistently).
Download manager with queuing
The script from http://jasonwhutchinson.com/blog/download_queue_dq_v0_2 implements a simple download manager with queuing management, relying on wget. Here is an update for max speed limit support (to avoid saturating your home DL bandwidth) File:Dq.sh
Aria2c is a powerfull download tool, does not handle download queuing, but support various protocols (including bittorent): http://aria2.sourceforge.net/ ('aria2' package is available with Ubuntu)
Tips and tricks
on Asus Maximus formula, do declare only 1 HDD in the HDD list for boot order. If several disks are defined, Linux willnot boot (grub cannot even start or show something on the screen)
Raid (SW) on Linux
Why choosing a SW RAID? (more details on the Wikipedia page)
- HW RAID is very expensive (and may no be so efficient)
- pseudo HW RAID embedded in many mother boards is in reality a hidden SW RAID managed by low-level motherboard drivers. It is not flexible, and does not provide means to test and monitor the status of the RAID clusters.
- SW RAID is now well supported by the Linux kernel and pretty easy to configure.
All infos on how to use mdadm are here: http://www.linuxfoundation.org/collaborate/workgroups/linux-raid/group
mdadm man page: http://man-wiki.net/index.php/8:mdadm
http://ubuntuforums.org/showthread.php?t=408461
Monitoring a raid array: http://www.linuxfoundation.org/collaborate/workgroups/linux-raid/detecting,_querying_and_testing
Main commands
check status:
cat /proc/mdstat
check a raid array state:
mdadm --detail /dev/md0
To restart the service at startup:
# Reload support for RAID1 sudo modeprobe raid1 # Reload a RAID cluster sudo mdadm --assemble --scan --uid=a0c330dc:22d35709:f2558bf9:2209550c # Then mount the drive if not already done through /etc/fstab
=> This script is inserted at: /etc/rc2.d/S80start-raid -> ../init.d/start-raid -> start-raid.sh
Monitoring (as a daemon):
mdadm --monitor -f --mail=my-email@address.com --delay=1800 /dev/md0
Raid 5 partitionning
According to http://www.linuxfoundation.org/collaborate/workgroups/linux-raid/raid_setup, for a Raid 5 array with a total of 3 disks:
- chunk size = 64kB (ok with relatively small file-systems) - block size = 4kB - stride = chunk / block = 64/4 = 16kB - stripe width = stride * (n data disks in raid5) = 16kb * (3 - 1) = 32kB
=> so using following commands to create / format the RAID5 partition:
sudo mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/sdb1 /dev/sdc1 /dev/sde1 sudo mkfs.ext4 -v -m .1 -b 4096 -E stride=16,stripe-width=32 /dev/md0
These parameters can be checked using:
sudo tune2fs -l /dev/md0
(or updated using tune2fs)
Then to automate the array assembling and mounting at boot, edit following files:
/etc/mdadm/mdadm.conf /etc/fstab /etc/samba/smb.conf
Email configuration
source: http://forum.ovh.com/showthread.php?t=42403
install:
apt-get install ssmtp mailx
Configuration du fichier /etc/ssmtp/ssmtp.conf:
UseTLS=YES UseSTARTTLS=YES mailhub=smtp.gmail.com:587 rewriteDomain=gmail.com hostname=ksXXXXX.kimsufi.com FromLineOverride=YES AuthUser=expediteur@gmail.com AuthPass=motdepassegmail
Envoi du mail (to send email):
mailx -s sujetdumail -a "from:expediteur@gmail.com" destinataire@domaine.com < textedumail.txt
Backup (copies) using rsync
Backup script using rsync for a rotating backup using hard-links: http://www.sanitarium.net/golug/rsync_backups_2010.html
rsync quick startup: http://www.linux.com/news/enterprise/storage/8200-back-up-like-an-expert-with-rsync
misc commands:
evaluate folders size:
du -shc <path> ex: du -shc /mnt/share1/
evaluate folders size (1 level):
for f in *; do du -shc $f; done | grep -v total
== File system sharing==under linux (sshfs - fuse): http://www.debuntu.org/2006/04/27/39-mounting-a-fuse-filesystem-form-etcfstab http://mediakey.dk/~cc/how-to-mount-a-remote-filesystem-using-ssh-and-sshfs/
Double screen on Linux
Graphical card choice
http://www.generation-nt.com/reponses/achat-carte-graphique-et-double-ecran-entraide-1551521.html 7600 GS
Configuration
http://doc.ubuntu-fr.org/configurer_son_ecran http://doc.ubuntu-fr.org/configurer_son_ecran Debugging a display problem: http://forum.ubuntu-fr.org/viewtopic.php?pid=2259389#p2259389
Test http server
Use following commands to test if the http server is running or not: permits to separate a server issue to a more global network config issue:
> telnet 127.0.0.1 80 Trying 127.0.0.1... Connected to 127.0.0.1. Escape character is '^]'. > GET / HTTP/1.0 HTTP/1.1 200 OK Date: Thu, 14 Jan 2010 12:38:07 GMT Server: Apache/2.2.11 (Ubuntu) Last-Modified: Thu, 14 Jan 2010 10:49:16 GMT ETag: "336621-2d-47d1da36a0300" Accept-Ranges: bytes Content-Length: 45 Vary: Accept-Encoding Connection: close Content-Type: text/html<html><body>
It works!
</body></html>Connection closed by foreign host.
(Ref article: http://www.ozzu.com/hosting-forum/internal-server-error-500-t22806.html)
