I want to backup my server.
This is a brand new server and I tried clonezilla but it failed
I am trying to get a full backup where - I pop in a disk and reboot the server and the o/s on the disk comes into play and I am able to backup the hard disk
This is a Raid 5 configuration and could you please guide me to some enterprise level backup software either paid or free
Is this popularly called Bare metal backup
The cloning software in Linux that I know are based on the command "dd" which read sector-by-sector from one disk and write the same on another disk. As such it cannot possibly fail as nothing other than an mirror image of the hard disk is replicated, literally down to byte by byte.
dd clones empty space same as filled data so I believe Clonezila was designed to economize the time wasted on cloning empty spaces. Therefore Clonezola works fine for a normally stand alone hard disk. It is possible that it breaks down in a Raid 2 or 5 set as the position of every byte has significance because of the stripe operation. Therefore not cloning the empty spaces in this case might upset the Raid system.
My advise would be to clone each disk by the standard mean of using dd in a terminal, say from a source disk sda to a target disk sde:
You will need to clone each disk at a time.
dd if=/dev/sda of=/dev/sde bs=32256
I found cloning a block size equal to a full track of 63 sectors times 512 byes per sector about the optimum. Without specifying the bs parameter dd defaults to 512 bytes per record transfer and take a long time.
To ensure a perfect cloning you need the target disk either exactly the same size as the source or just larger. This is to satisfy the number of records from the source disk is fully executed. SUch can only be achieved only if the target disk has exact number of sectors as the source. Failing that the target disk cloning will be incomplete and the disk could have a defective partition table.
Say I have a HDD of 300 GB (sda) which I partition as follows
a) / 50 GB (/dev/sda1)
b) Swap 50 GB
c) boot 500 MB
d) remaining (/dev/sda2)
Now I take backup of each /dev/sda1 and /dev/sda2
The /dev/sda1 is 10 percent used and /dev/sda2 is 4 percent used
Now if I use PING or clonezilla to backup only the partitions sda1 and sda2
and If I replace the HDD of 300 GB with 290 GB
will clonezilla / PING be able to restore the partitions considering that
the space on the new sda1 and sda2 is a little less than original ....
But considering that usage is 10 percent and 4 percent ...does it matter ?
If you have to clone a bigger hard disk to a small hard disk, like using a 300Gb source on a 290GB target you need to resize the last partition's boundary (using Gparted) so that the number of sectors is within the capacity of the target disk.
You should clone the whole disk to allow the full compliment of sectors of the smaller disk runs its course or if you know how to calculate the number of records (size as per that specified in the bs parameter) you can use the "count" parameter to specify the exact number of records to be cloned.
If you don't do the above then your new cloned disk will have a partition table using a boundary larger than the physical disk and no operating system will touch it because none of them know what to do.
This is what I found
Clonezilla is available in two models
32 bit and 64 bit amd (amd 64 bit is also suitable for intel 64 bit)
However both the above do not work for me.
My drive is configured with physical disk/ logical volume manager lvm2
So To solve the issue I am trying the following
I downloaded a number of Linux Live CD's
none of them worked with the commands
pvscan, vgscan, vgdisplay, lvdisplay
only one of them Knoppix works with the above commands
so I am using Knoppix Live cd 6.7.1 2011-09-14 English version
I booted the server with the Live cd hence ensuring that the storage array disks (Raid 5)
are not being used....so No open files
Next I ran the following commands
pvscan - this scans for physical volumes
vgscan - this scans for logical volumes
I saw that the logical volumes are inactive
I ran the following command
vgchange -a y (this will make all logical volumes active)
next I mounted the external HDD
dd if=<logical Volume name> | gzip > <path of external hdd>/image.gz
in my case the exact command was
dd if=/dev/vg_proddb12/lv_home | gzip > /home/extdisk/back_20121221_dd/image_home.gz
I hope you guys comment on my solution.
It has been a long struggle to understand stuff in Linux