Most of my systems run on a software RAID 1 configuration (that is, two disks, where each disk is mirrored to the other). This way, one of the disks can fail and still all the data is available.
If a disk failure happens, the disk is replaced with a similar disk, and then needs to be configured and re-added to the RAID.
Newer systems all use the GUID partition table (GPT), and therefore allow almost unlimited disk sized. Instructions for re-adding a disk using GPT are a bit different from the days when MBR (up to 2 TB disk space) was used, therefore I'm writing them down here for future use.
Continue reading "Replace and re-add a failed drive to a Linux software RAID"
New server, S-ATA disks, the hardware RAID controller is not really supported. So we decided to use a software RAID 1 for the two disks. Here are the steps to create the RAID:
- Boot the Debian Etch installer.
- If the installation comes to "Partition method", use "Manual".
- In the following menu, scroll to your first disk and hit enter: the partitionier asks you, if you want to create an empty partition table. Say "yes". (Hint: this will erase your existing data, if any.)
- The partitioner is back in the disk overview, scroll one line downwards over the line with "FREE SPACE" and hit enter.
- Create a partition with the size you need, but remember the size and the logical type.
- In the "Partition settings" menu, go to "Use as" and hit enter.
- Change the type to "physical volume for RAID".
- Finish this partition with "Done setting up the partition".
- Create other partitions on the same disk, if you like.
- Now repeat all the steps from the first disk for the second disk.
- After this, you should have at least two disks with the same partition schema and all partitions (beside swap) should be marked for RAID use.
- Now look at the first menu entry in the partitioner menu, there is a new line: "Configure software RAID". Go into this menu.
- Answer the question, if you like to write the changes, with "Yes".
- Now pick "Create MD device".
- Use RAID1 and give the number of active and spare devices (2 and 0 in our case).
- In the following menu, select the same device number on the first and second disk and Continue.
- Repeat this step for every two devices until you are done. Then use "Finish" from the Multidisk configuration options.
- You are back in the partitioner menu and now you see one ore more new partitions named as "Software RAID Device". You can use this partitions like any normal partition and continue installing your system.
Thanks to mastermind from #postgresql-de for all the help.