NASLite Network Attached Storage

Does NASLite work in conjuction with the Intel® Matrix Storage Technology (RAID) function in the ICH7R southbridge? Does anybody have any comments about this RAID feature from Intel?

I guess my question is should I seek out a motherboard with this feature or should I spend more money to buy a RAID card?

I've also seen comments about Software RAID vs. Hardware RAID but I don't quite follow the functional differences.

Thanks

It is actualy fairly simple. RAID0, RAID1, and RAID0+1 are all easly implemented in drivers since there is no parity generation or checking needed. Most, I only know of one hardware based, cards that are one of the above RAIDs are implemented in the drivers. Hence no support in NASLite.

If I were you I would buy a hardware RAID calr like on of the 3Ware, LSI or Promise controlers. I believe the Intel solution is software based.

Mike

RAID does it's stuff by storing your data on different disks and in some cases also storing parity data which will allow it to recreate the data that would be lost when a drive fails.

The difference between hardware RAID and software RAID is centered upon where the calculations related to this parity data occur - if there is a separate dedicated processor, it is hardware RAID and the calculations are handled by the system processor, it is software RAID.

There are some RAID levels, where no parity calculations are required, these are RAID-0, where the data is striped across different drives, primarily for speed, and RAID-1 or mirroring, where the same data is written to two drives. There are also combinations of these two levels known as RAID 10, RAID 1+0 & RAID 0+1.

It was once quite simple to differentiate hardware RAID from software RAID - with hardware RAID, ALL of the RAID complexities were handled by the hardware and the operating system saw only the logical drives whilst with software RAID, the operating system was directly involved and knew every detail - I like to refer to this as "OS driven RAID".

In recent years it has become quite common to find the simpler (non-parity) RAID implementations being handled by the disk controller drivers - in which case, the RAID complexities are again hidden from the operating system, and it is this that creates the confusion surrounding software RAID - the processing is still being done by the system processor, but the OS is not involved. I call this "driver based RAID"

It can be difficult to determine if a RAID implementation is "true hardware" (ie has a dedicated processor) or is "driver based", but if it only supports the non parity levels (0,1, etc.) there's a strong probability that there is no dedicated processor.

You can find out more about the Intel Matrix RAID here - the ICH7 chipset implementations are two port, and most likely driver based.

Like Mike says, buy a hardware card - 3Ware or LSI Logic.

I've got the drives installed now and things don't seem right to me just yet. In the BIOS, I have set the four SATA drives to be a RAID5 array. This machine is using the ICH7R, as I mentioned before. I can choose CTRL-I at startup to configure this drive array, so I thought when I got to the NASLite install, it would be fine.

When I boot on the NASLite-USB flash drive, it still sees the hardware as four separate drives, and not one unified RAID5 array.

I thought the BIOS was going to present the drives to the OS as one single array? What is going on? I've done similar things with Windows XP using SiliconImage SATA controllers, and even without any special driver loaded, Windows sees the array as one big drive. The BIOS masks the drive configuration from the OS. I thought NASLite would let me do that too.

I'll dig through the BIOS manual, to see if there's a setting I've missed somewhere. If you have any advice, I'd appreciate it.

Thanks,
James

The fact that the BIOS lets you set RAID5 suggests that you do have hardware RAID, however, NASLite showing you four individual drives is an indication that it recognizes your disk controller as a disk controller and not a RAID controller, quite possibly because it is not hardware RAID, but driver based RAID.

With regard your Windows & SiliconImage experiences - Windows, like every other operating system has to have a driver loaded for every hardware device, your not having to load one simply means that your hardware is popular enough that Microsoft includes the driver with Windows.