> I have two on-board sata controller chips with each their version of HW > RAID (NVIDIA and SIL) I don't know of any nVIdia or Silicon Image onboard chips that can do raid in HW. Most likely it's BIOS-assisted software RAID. The 3ware should be the real article. > I think there is a tendency that SW raid like Linux kernel MD and Sun ZFS > etc are more intelligent and can thus obtain better performance than HW > RAID. Performance is one thing, flexibility is another ... - end-to-end checksumming - ECC-on-read and / or bg scrubbing - arbitrary percentage of parity data (fs-level PAR2) - virtualized storage pools with actual backing store chosen based on usage hints - all configurable rule-based with file level granularity Sort of like a stable ZFS+raif variant ... one can only dream :-) > HW RAID has the advantage as Bill says that you only need to > transfer the data once when writing, and that parity calculation is > offloaded from the main CPUs. Yes, maybe current cards conserve bus bandwidth even for RAID 10. Mine doesn't, and there's no parity to offload. I don't like HW controllers much since the on-disk format is closed ... if the controller dies you have to get a very similar one, which can be a pain. > If you reuse older hw, then I would say that you really have a problem > with the PCI bus here, and that a motherboard with better bus > performance The board has 5 bus segments, only most are PCIe. Boards with decent PCI slots are getting hard to find ... Nah, I'll just live with it until the disks start croaking ^^ Thanks, C. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
