Hello,

I would like to know if there is a way to have to logical partitions on my Linux system, and then bascul from one to another in order to recover a bad state of the primary. For example; let's supose i have a two partitions on my hardisk (just one HDD), in main partition i have my database and apache web server (for example) with version 2.0 on both; and on inactive partition, i have mysql and apache with 1.0, so, in case of an emergency or bug detected on partition 1, could i bascul to the second partition? this is something applied on OXE ip-pbx (Linux OS) from Alcatel-Lucent. Is this possible to do? i'm kind of newbie on partitionin within linux.

Thanks so much!

What do you mean by "bascul"..?

Could it be this?
http://www.jpfleury.net/en/software/bascule.php
If so, is has no relevance to switching partitions.

I'm not totally clear what you want to do, but let me guess: You have a process running under Linux (installed on partition A. If there is a problem, you want to switch control to the same code / environment on a different partition.

Hi,

Exactly, that's what i want!

I do not know of a way to do that, but here are some things to think about.

First, I don't know why it would have to be a different partition---i.e. I think you just want another instance of the SW. If you are concerned about a HW failure, then you'd want a different physical disk.

Second, I'd assume that this would involve code running outside of the process in question. The process would export diagnostic data which the watchdog program would use to determine if action was required. My question would be --What happens when the watchdog fails?

Hopefully, a real programmer will step in here pretty quick.... Meanwhile, I'd try googling on--eg--"redundant software", "fail-safe software", or something similar.

Yes You can create lvm (logical volume manager) for a separate partition.. Lvm is created from harddisk partition and application assumes it as a separate drive... to create lvm you will have to create partition using fdisk or parted command ; -
eg. fdisk -cu /dev/sda
or
parted /dev/sda
there create a partition
after creating partiton set the type to 8e which is for lvm partition
write the partition and exit
Next run partx -a /dev/sda .. You might have to run it twice..It will force the kernel to reread the partition table..which you can verify using fdik -l
Now create physical volume ,volume group and then logical volume. eg:-

pvcreate /dev/sda5
pvdisplay
vgcreate -s 8M VolumeGroup /dev/sda5
-s 8M will set the PE size as 8M... so when you will create logical volume you can set it exact size using PE...such as 100 for 800MB logical volume.
vgdisplay
lvcreate -l 100 -n logicalvolume Volumegroup
lvdisplay
here -n is used to set the logical volume name as logicalvolume
logical volume will be created...
Now format partition as :-
mkfs.ext4 /dev/VolumeGroup/logicalvoulem
to mount it at boot time..enter the entry in /etc/fstab as : -
vim /etc/fstab
/dev/VolumeGroup/logicalvolume /mnt ext4 defaults 0 0
:wq
mount -a
verify using :-
df -TH