this is a quote from the sandman, from my previous thread - can anyone elaborate on this statement:


"off you are going to have issues with arrays over 2TB.
Yes highpoint blows on the high end. "


Why are 3TB or 4TB arrays an issue? we plan hooking 8 hdd in raid 5 with lsi logic card.

thank you for any input!

Doesn't x64 exceed the 2T limit as well?

Volume, partition and file size limits don't rely on architecture limitations: it's only an OS limit: even an 8 bit MCU can handle 64 bit long long integers (grouping 8 consecutive bytes together), it's only a matter of OS implementation.

Wrong, with ANY version of windows (on x86) there is a limit of 2TB on the boot ARRAY, this is because this is the maximum an array with MBR can support. I have a system witn Windows 2003 SP1, and a 5TB boot array, I had to scrap this in the end and create 3 smaller arrays before I could use the space.

You can use an aray with more then 2TB as a data disk, but you need to use GPT arrays, and you CAN NOT BOOT FROM THEM

http://technet2.microsoft.com/Wind [...] x?mfr=true

I do believe that is what I said.

Anyway, they are working on a larger than 2TB bootable partition for 2003.

@maury73
Yes there are hardware limitations that can limit the array size to 2TB. It is not completely inclusive to the OS. I believe adaptec is still having issues with the 2TB limit. Most newer controller cards will specifically mention "greater than 2TB" in the specs or state the maximum by mentioning something like "32TB LUN support."

Thanks you actually found the link for me. I knew I wasnt imagining things.

EFI is not necessary for greater than 2TB boot recognition. Now as soon as I find the link where they are implementing this for W2K3 I'll post it.

Sorry, but jamesgoddard is correct. EFI is most certainly necessary for boot partitions to reside on a device with > 2^32 blocks (2TB).

The quotes you refer to are correct for large (> 2TB) arrays in general when used as data-only arrays, not boot arrays.

I recently set up a Windows Server 2003 with a 6TB iSCSI array, and learned a few things while I did it. 8)

Here is a summary:

1. The only versions of Windows that support >2 TB arrays at all are Windows XP x64, Windows Server 2003 SP1 (x86 and x64), and Windows Vista (x86 and x64).

2. The only versions of Windows that can use a >2 TB array as a boot device are Windows Vista and the not-yet-released Longhorn server. They can only do this on a system with an EFI BIOS. Any system with a standard PC BIOS cannot boot from a >2 TB array regardless of operating system.

3. To support an array >2 TB, the device must be converted to a GPT disk in Windows Disk Management.

4. To support a device >2 TB, the controller must support some type of extended addressing mechanism (48-bit LBA for IDE/SATA devices, 64-bit LBA / 16-byte CDB for SCSI API-compatible controllers). If the controller doesn't support this, the maximum array size it can support is 2TB.

5. Some controllers will assist you in hooking up a large array to an operating system that doesn't support it (such as Windows XP) by using LUN carving. Using this, a large array appears to the computer as multiple 2TB arrays. Each 2TB virtual array can then be formatted as a standard MBR disk. Of course, not all of your space will be on one volume.

6. The FAT32 file system is not supported on arrays >2TB. Volumes >2TB must be NTFS. NTFS will support up to a 256TB array in its current implementation.

7. It is recommended that >2TB arrays be basic disks unless absolutely necessary to make them dynamic disks. Dynamic disks are only supported on devices that are direct connected or connected on a SAN through a Fibre Channel card or iSCSI hardware card. Dynamic disks are not supported using the Microsoft iSCSI software initiator.

8. Some RAID controllers and SAN units have a hack that is supposed to let them get around the 2TB limit on operating systems that don't support it. To implement it, they increase the sector size from the standard 512 bytes up to as large as 4096 bytes. Using this, they purport to be able to support up to a 16 TB array as an MBR disk. Do not use this mechanism under Windows. Windows specifically does not support any device with a sector size other than 512 bytes. Under Linux OS's, this should work OK.

To anybody thinking about Volums >2TB on clustered Windows Servers follwo this link:

http://technet2.microsoft.com/Wind [...] x?mfr=true

Note what they wrote:

• You cannot use the GPT partitioning style on removable media, or on cluster disks that are connected to shared SCSI or Fibre Channel buses used by the Cluster service.

So, if you are running clusterd (failover cluster) Servers, you will be allways limited to max. partition size 2TB.

Why would you want a boot partition larger than 2 TB? Why would you want one even close to that size?

we have had problems in past with multiple drives and multiple media extenders. it appears if the movies are stored on single drive or in this case a single large partition of 8 x 500gb drives then we have less problems with lag for lack of a better word - when watching 3 different movies using xbox 360's as a media extender on 3 different tv's it seem to work better with a single drive.

Its not just a matter of Partitions being over 2TB. Its a matter of the Volume being over 2TB that freaks out Windows for boot.

I recently helped a friend upgrade his rig and we went with 5 x WD6400AAKS drives which would give us around 2.3 TB. We planned to carve out 400GB or so and use this for OS and Apps and Games and then use the remaining 1.9TB as a large MBR storage partition.

However since he was on a 680i, the RAID setup doesnt offer you the ability to either create multiple volumes on a single RAID Group or do Intel's "Matrix RAID".

This means Windows Vista x64 boot DVD sees it as 1 HDD and instead of showing 2.3TB it shows like 320GB (the Wrap around mentioned in this thread previously).
We installed to that partition hoping the other 2TB would be listed as unused after we get into the OS and get the latest nForce drivers on there but the other 2TB never shows up.

So if your on an nForece board (680, 780, 790) beware of large single arrays and booting from them AT ALL.
You would be better off doing a small boot drive or RAID0 with something like Raptors and then save the uber arrays for storage.

I almost told him we should just hook up a 40GB IDE Drive and boot from that and then create a 400GB D: and a 1.9TB E: and just put all his apps and games on D: and use C: for ONLY the OS. Somehow I didnt think he would go for that so we ended up doing a 1.2TB RAID0 with 2 drives and then a 1.2TB Using RAID5. Problem is even with all the latest games and apps on C:, hes never going to fill that drive and now D: is limited to 1.2 when it should have been 1.9 or so.

I so wished he had an Intel board at that moment.
But then he couldnt run his SLI setup.
So once again the fighting of the big companies screws the consumer.

This was already discussed in this thread.

First, the limitation is on the boot device, not the boot partition. The boot device cannot be larger than 2TB, regardless of the partitions that are on it.

The reason for that is that the PC standard BIOS cannot address a device that is larger than 2TB, because the PC BIOS is designed as a 32-bit system. The BIOS can load the OS files on a device up to the 2^32 block, after that, the BIOS has no way to address blocks that are further out on the device. So if ntkernel or ntldr (for Windows) resides on a block past 2^32 (which would be legal on a device that's bigger than 2TB), the BIOS cannot load that file, thus the machine won't boot.

Now, you might think that if the boot partition resides completely within the first 2TB that you'd be OK, but that's not the case. When the BIOS goes to access the device, it has to know its size, and if the size is larger than 2TB, it can't address it.

The Itanium machines have an EFI BIOS, a new and completely different BIOS that has the ability to address blocks up to 2^64 on the boot device. Thus, it can boot to a device larger than 2TB.

After everything was cleared up in this thread, it was stated that a >2TB boot device is not supported on normal PC hardware, regardless of operating system. (See #2 in my first post in the thread).