Growing a RAID Array on a Dell PERC 6 Controller

  • Can you grow a RAID array on a Dell PERC 6 hardware RAID controller?

    Often this is a complex question. Dell's PERC 6 documentation tells us that arrays of RAID 10, 50 & 60 cannot be grown.

    From the documentation: Administrators can expand the virtual disk size without an OS reboot for supported RAID levels other than RAID-10, RAID-50, and RAID-60.

    For the PERC 6 controller, online array expansion is limited to the additional new drives, and not a move to larger drives that replace the originals. So for RAID 5 and 6 arrays, adding new drives would allow for a parity-based array growth operation. But replacing, for example, 1TB drives with 2TB drives would not grow the array. You could create a second array utilizing the unused space of the new, larger drives for a complicated and very much less than ideal dual array system which would have performance and reliability implications beyond maintenance headaches.

    Dell Community Documentation on Limits of PERC 6 RAID Growth