I've recently created a file server using an Adaptec RAID 31605 controller, and I currently have 8 750GB Samsung Spinpoint F1 drives connected into a RAID array.

I've been planning to do a sort of RAID6 for now with these eight drives, and as the 31605 is a 16-port SATA/SAS RAID controller, I was wondering whether or not it's possible to add 8 more drives in the future (to utilize all four SFF-8087 ports) without having to migrate/transfer the data and rebuild to utilize all 16 disks in RAID6.

If anyone has any direct experience with 31605s regarding this question, or any Adaptec products in general, I'd greatly appreciate whether or not this is even possible with these cards, and how it can be done.

You can add 8 more drives in the future and expand the size of the array you already have. I assume you would use the same drives. This will give you a windows volume larger than what you have. If you want to keep all this in 1 drive letter you will need to either resize the partition you have or delete and re-create the partition.

So, I'm assuming there's no way to expand the array via the hardware controller? The array is formatted in NTFS, so I guess in Windows there may be issues with expandability, but is there no way to expand the arrays and create a partition through parity rebuilding into one large, contingious partition without having to backup/dump/restore?

When you say expand the array via the hardware controller and create a partition through parity rebuilding into one large, contingious partition without having to backup/dump/restore, those are 2 different steps. Expanding the array is 1 step which in windows will give you more useable space on the volume. In disk manager for instance if disk 1 were your array you will see more unpartitioned space on that disk. Step 2 would be in windows and this is how you use that space, you can try to resize the partition you have that has data on it now and use the entire volume/disk to be 1 drive letter/partition or you can delete the partition you have and re-create it using the entire volume and have it all in 1 drive letter in windows.

I do not know of a utility that will re-size a partition that big, maybe somebody reading this can help. I assume it is a GUID Partition formatted NTFS now and about 4.7 TB in size.

Windows XP x64, Windows Server 2003 SP1, Windows Server 2008, and Windows Vista have a built-in command line utility called DISKPART that can expand a GPT data partition.

See this thread for details.

Using this method, would this mean that any sort of RAID would be software-based? I created my initial array using the Adaptec controller, and then formatted in NTFS with Windows Server 2008; would this method tie me down to my current OS install in terms of the NTFS DISKPART file system?

No. The file system (NTFS) and the RAID operation are two different things.

The RAID operation is the portion that is responsible for taking several physical drives and using one of several different redundancy schemes (like RAID 1, RAID 5, or RAID 6) to make the several physical drives look like one logical drive to the computer. The RAID operation can be software-based (done primarily in the driver software), or can be hardware-based (the RAID controller performs all functions).

The file system is responsible for creating a partition on a device and creating directory structures to keep track of all the files. The file system's tasks are always software-based, and are part of the operating system. Windows uses primarily the NTFS file system. Linux OS's typically use EXT2 or EXT3 file systems. There are others for other OS's.

If you have a RAID array and want to expand its size without losing data, that is a 2-part operation:

1. The RAID controller must be able to add a drive to the array and rearrange the data and redundancy information so that the logical drive looks bigger. Most hardware-based enterprise-level RAID controllers can do this, they generally call this operation Online Capacity Expansion (OCE). This operation is independent of the OS on the computer. Thus, you have to do this step whether you're running Windows, Linux, or anything else.

2. The second step is to expand the partition that's on the logical device so that the computer and OS have more space to actually store more files. This operation is dependent on the file system that was chosen, and expanding the partition without losing data is a task that only a few software programs can do.

Software programs that can expand an NTFS partition without losing data include Symantec's Partition Magic, the freeware GParted, and a few others. However, all of these suffer from a particular problem - they don't work with partitions that are larger than 2TB. Your array is larger than this, so you need a different tool.

The DISKPART program is a tool that can expand an NTFS partition that is larger than 2TB. You would run this according to the instructions I previously referenced to expand your partition (after you've performed the OCE via the RAID controller software).

Thanks so much for your info, that was exactly what I needed to know!

The term "Online Capacity Expansion" makes Google searching much, much easier.

Kudos.