administration:system-mirror
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| administration:system-mirror [2008/03/12 20:29] – damir | administration:system-mirror [2008/11/24 11:36] – damir | ||
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| ===== Prologue ===== | ===== Prologue ===== | ||
| - | * with the instructions that follow we move a complete root system disk from bare partitions to a raid 1 software layer. | + | * with the instructions that follow we move a complete root system disk from bare partitions to a RAID 1 software layer. |
| - | * all the work is done without putting the server off-line, but it's better to stop the services before starting the copy of the files from the old disk to the new one. | + | |
| + | * **all the work is done without putting the server off-line, but it's better to stop the services before starting the copy of the files from the old disk to the new one** | ||
| * only one reboot process is needed if the disks are already installed on the server and if the whole process is correct. | * only one reboot process is needed if the disks are already installed on the server and if the whole process is correct. | ||
| Line 13: | Line 14: | ||
| * /dev/sda: is the original disk from where the system boot | * /dev/sda: is the original disk from where the system boot | ||
| * /dev/sdb: is the second disk | * /dev/sdb: is the second disk | ||
| - | \\ | + | |
| - | === create the correct partitions we need === | + | ==== create the correct partitions we need ==== |
| * 100 MB for the boot partition | * 100 MB for the boot partition | ||
| * 2Gbyte for the swap partition (there' | * 2Gbyte for the swap partition (there' | ||
| Line 47: | Line 48: | ||
| - | === now we need to create the raid 1 partitions for the boot and the other partitions === | + | ==== now we need to create the raid 1 partitions for the boot and the other partitions |
| * /dev/md0 will be the first raid 1 partition used only by the /boot directory | * /dev/md0 will be the first raid 1 partition used only by the /boot directory | ||
| * /dev/md1 will be the raid 1 disk used for everything else | * /dev/md1 will be the raid 1 disk used for everything else | ||
| Line 61: | Line 62: | ||
| * the informations about the devices is written in the **/ | * the informations about the devices is written in the **/ | ||
| - | === the /dev/md0 partition will be used flat for the boot partitions === | + | ==== the /dev/md0 partition will be used flat for the boot partitions ==== |
| + | * so we can format it right now | ||
| < | < | ||
| mkfs.ext3 /dev/md0 | mkfs.ext3 /dev/md0 | ||
| </ | </ | ||
| - | === the /dev/md1 partition will be splitted using the lvm layer === | + | ==== the /dev/md1 partition will be splitted using the lvm layer ==== |
| * if the virtual disk **vg1** is already used, please change the example below | * if the virtual disk **vg1** is already used, please change the example below | ||
| < | < | ||
| Line 85: | Line 87: | ||
| mkfs.ext3 / | mkfs.ext3 / | ||
| mkfs.ext3 / | mkfs.ext3 / | ||
| - | mkfs.ext3 /dev/md0 | ||
| </ | </ | ||
| - | === time to mount the partitions to copy the system from the original disk === | + | ==== time to mount the partitions to copy the system from the original disk ==== |
| < | < | ||
| mkdir /1 | mkdir /1 | ||
| Line 106: | Line 107: | ||
| * wait until the system is copied | * wait until the system is copied | ||
| | | ||
| - | === Create the new initrd image file === | + | |
| - | * after the copy we need to create a new initrd and change the information in the /etc/fstab file | + | ==== Create the new initrd image file ==== |
| + | * after the copy we need to create a new initrd and change the information in the **/1/etc/fstab** file | ||
| * avoid the use of label inside this file, instead use the physical name of the devices | * avoid the use of label inside this file, instead use the physical name of the devices | ||
| * you should have something like that: | * you should have something like that: | ||
| < | < | ||
| + | vi / | ||
| + | |||
| / | / | ||
| / | / | ||
| Line 125: | Line 129: | ||
| * the reference to the swap partition on the first disk must be commented | * the reference to the swap partition on the first disk must be commented | ||
| - | * now we can create the new initrd image | + | * now we can create the new initrd image **include also the serial-ata module, if necessary** |
| < | < | ||
| - | mkinitrd --preload raid1 --preload raid456 --fstab / | + | mkinitrd --preload raid1 --preload raid456 |
| </ | </ | ||
| - | === Edit the grub configuration file in the original disk === | + | |
| + | ==== Edit the grub configuration file in the original disk ==== | ||
| * change the file adding a instance forthe new disk | * change the file adding a instance forthe new disk | ||
| * this is the original instance: | * this is the original instance: | ||
| Line 149: | Line 154: | ||
| root (hd1,0) | root (hd1,0) | ||
| kernel / | kernel / | ||
| - | initrd / | + | initrd / |
| </ | </ | ||
| * leave the default boot partition to the old disk, so in case of trouble we can reboot | * leave the default boot partition to the old disk, so in case of trouble we can reboot | ||
| - | === Install the boot loader on the second disk === | + | ==== Install the boot loader on the second disk ==== |
| * we need to install the grub boot loader on the new disk using the **grub** command | * we need to install the grub boot loader on the new disk using the **grub** command | ||
| * avoid the **grub-install** command, doesn' | * avoid the **grub-install** command, doesn' | ||
| Line 165: | Line 170: | ||
| </ | </ | ||
| - | === update the data on the second disk === | + | ==== update the data on the second disk ==== |
| * we need to copy the changes from the original disk to the new one | * we need to copy the changes from the original disk to the new one | ||
| Line 172: | Line 177: | ||
| </ | </ | ||
| - | === Reboot === | + | |
| + | ==== Reboot | ||
| * time to reboot and see what happens | * time to reboot and see what happens | ||
| < | < | ||
| Line 178: | Line 184: | ||
| </ | </ | ||
| - | * at the boot prompt select the second boot option and verify that is the right one checking that contains the **root (hd1,0)** line | + | |
| * if everything was right the system should boot with the raid 1 disk | * if everything was right the system should boot with the raid 1 disk | ||
| - | ==== The New System ==== | + | ===== The New System |
| * now we have the system running on the software raid disk, but the raid is in downgrade mode (only one disk is operating at the moment) | * now we have the system running on the software raid disk, but the raid is in downgrade mode (only one disk is operating at the moment) | ||
| * we need to connect the original disk tho the current one | * we need to connect the original disk tho the current one | ||
| Line 189: | Line 195: | ||
| * in our examples /dev/vg0 is the old lvm disk | * in our examples /dev/vg0 is the old lvm disk | ||
| - | === Deleting the old lvm partitions === | + | ==== Deleting the old lvm partitions |
| * we disable the old lvm partitions to avoid confusion | * we disable the old lvm partitions to avoid confusion | ||
| < | < | ||
| Line 212: | Line 218: | ||
| </ | </ | ||
| - | == Creating the new partition table form the second disk === | + | ==== Creating the new partition table form the second disk ==== |
| * now we can recreate the new partition table copying the partition of /dev/sdb to /dev/sda | * now we can recreate the new partition table copying the partition of /dev/sdb to /dev/sda | ||
| < | < | ||
| Line 218: | Line 224: | ||
| </ | </ | ||
| | | ||
| - | === add the second disk to the raid system === | + | ==== add the second disk to the raid system |
| < | < | ||
| Line 226: | Line 232: | ||
| * the raid subsystem is synchronizing the content of both disks | * the raid subsystem is synchronizing the content of both disks | ||
| - | === one last task is to create the second swap partition === | + | ==== one last task is to create the second swap partition |
| < | < | ||
| Line 235: | Line 241: | ||
| * uncomment the line about he swap partition inside /etc/fstab | * uncomment the line about he swap partition inside /etc/fstab | ||
| - | ==== Kernel upgrade ==== | + | ===== Kernel upgrade |
| **During Kernel upgrade the grub file must be manually modified in order to add the reference to the second disk** | **During Kernel upgrade the grub file must be manually modified in order to add the reference to the second disk** | ||
administration/system-mirror.txt · Last modified: 2009/03/16 15:00 by damir