Expanding a Raid5 filesystem

[Jim Ford]

I was so pleased at the performance of my raid5 setup that I decided to try adding another disk. I altered the raidtab to show the new partition (not as a spare) and rebooted. The new partition was detected OK but was added to md0 as a spare, which was not as I hoped for. I had hoped that it would just add to md0 according to the formula in the HOWTO  (N-1)*S, thus increasing the available disk space. /dev/mdstat showed that it was part of md0, but the size of md0 hadn't changed. I also found that even if I marked the new partition as a failed-disk in the raidtab, the system still insisted on using it - it's only when I physically remove the disk that the array is reconstructed. How do I add a new partition to an existing raid5 array?   Regards: Jim Ford