Linux, programming and more
Next Generation Remote Display – NX is an exciting new technology for remote display. It provides near local speed application responsiveness over high latency, low bandwidth links.
Was tested on Ubuntu 10.10 Codenamed “Maverick Meerkat”. Works on Debian 6 too;)
Edit your source list or create a new one:
1 | vim /etc/apt/sources.list.d/freenx.list |
Some days ago I wrote a similar post about nagios and lighty, now I decided to test Icinga on Debian Squeeze.
The installation was pretty easy:
1 2 | aptitude install lighttpd aptitude install icinga |
To use Icinga we need following modules:
The simple way to install grub/ grub2 from any linux live-CD or any other bootable medium.
Step 1: boot from linux live CD/DVD or even USB
Step 2: mount your hdd
Step 3: chroot in the mounted filesystem
Step 3: install grub
Step 4: reboot
1 2 3 4 5 6 7 8 9 | fdisk -l mount /dev/sda1 /mnt/ mount -t proc none /mnt/proc mount -o bind /dev /mnt/dev mount -t sysfs sys /mnt/sys chroot /mnt/ /bin/bash update-grub /usr/sbin/grub-install --recheck --no-floppy /dev/sda sync & reboot |
SUSE Syntax:
update-grub is debian and ubuntu little helper this execute the same as:
1 2 3 | grub2-install --recheck --no-floppy /dev/sda grub2-mkconfig -o /boot/grub2/grub.cfg mkinitrd |
There are many configuration options with inpact on performance in Roundcube and behind it (Database and Webserver). As Roundcube installation administrator you can set them to some defaults and prevent users to change them by using the ‘dont_override‘ option.
I tested some options and created my tiny boost list.
Here’s the list of options with impact on performance
Messages listing is a main task of a mail client. Sorting is expensive. First of all you should use an IMAP server with SORT capability. If message list displaying is still too slow you should set ‘message_sort_col’ to an empty string.
‘message_sort_col’
[Read more…]
physical volumes:
These are your physical disks, or disk partitions, such as /dev/hda or /dev/hdb1. These are what you’d be used to using when mounting/unmounting things. Using LVM we can combine multiple physical volumes into volume groups.
volume groups:
A volume group is comprised of real physical volumes, and is the storage used to create logical volumes which you can create/resize/remove and use. You can consider a volume group as a “virtual partition” which is comprised of an arbitary number of physical volumes.
logical volumes:
These are the volumes that you’ll ultimately end up mounting upon your system. They can be added, removed, and resized on the fly. Since these are contained in the volume groups they can be bigger than any single physical volume you might have. (ie. 4x5Gb drives can be combined into one 20Gb volume group, and you can then create two 10Gb logical volumes.)
apt-get update && apt-get install lvm2 |
pvcreate /dev/md0 |
Once we’ve initialised the partitions, or drives, we will create a volume group which is built up of them:
vgcreate storm /dev/md0 |
If you’ve done this correctly you’ll be able to see it included in the output of:
vgscan |
Create your first logical volume:
lvcreate -n data --size 300g storm |
Your new logical volume will be accessible via:
/dev/storm/data # or /dev/mapper/storm-data |
Create file system:
mkfs.ext4 /dev/storm/data |
Show created volumes and their sizes:
lvdisplay |
Extend volume:
lvextend -L+10g /dev/storm/data |
After resizing you should resize the filesystem:
e2fsck -f /dev/storm/data resize2fs /dev/storm/data |
Remove volume:
lvremove /dev/storm/data |
If you need some visual help you can use: “system-config-lvm” utility co configure LVM.
First thing to say it’s a kind of RAID0; if you have the need of a single big partition but you have only multiple smaller disks, you have the possibility to crate a LVM-stripe over all your smaller disks.
In this example I have 4x 4TiB devices which will be used to create a single one with 16TiB
pvcreate /dev/sdb /dev/sdc /dev/sde /dev/sdd # verify with: vgdisplay to verify |
lvcreate -l 100%FREE -n storage backups # to verify: lvdisplay |
Create a filesystem on your 16TiB device:
mkfs.xfs -L storage /dev/mapper/storage-bacula |