2TB iSCSI limit

[OverWorked]

I've just bought two 4TB Buffalo Terastation III iSCSI devices for backup.

I've connected with the iSCSI initiator OK.

In the disk manager, it shows a 2751 GB disk. The disk is divided into 2 unallocated spaces (2048GB and 703GB). I can create a 2048 GB partition on the first space, but can't do anything with the other 703GB - it remains unallocated. I expected to see one space of about 3TB (after RAID-5).

I'm new to iSCSI. Is there a 2TB limit? How do I access the full drive space?

Help!

[AngryTechnician]

I don't think iSCSI has a limit, but my Netgear NAS had a 2TB limit on a single iSCSI target until a recent update. Have you dug into the Buffula docs to see if it's a limitation of the box itself?

[box_l]

In windows disk manager can you convert the volume to GPT?

BoX

[AngryTechnician]

Ah, yes, that's probably it. 'Basic' MBR disks can only have partitions of up to 2TB. Not everything supports GPT so the Buffalo is probably formatted for MBR by default.

[jamesfed]

I could well be wrong but I thought iSCSI works in a way that it presents a raw disk to the OS that using it and that in disk management you have to then select GPT or MBR? In this setup the storage device is unaware of the nature of the drives (MBR or otherwise) and so you should only need to configure the RAID array and iSCSI connection settings on the storage box leaving anything to do with formatting alone.

As said before MBR will only do for 2TB and any higher you need GPT.

[CyberNerd]

im pretty sure there is a 2TB limit, at least in some implementations

[Rozzer]

I have a 10TB Lacie iSCSI drive with a 8TB iSCSI. But I have not partitions 2TB on as its used for DPM 2010.

Ross

[box_l]

I have an MD 3200i that had this issue. The raw LUNs were raw, but windows defaults to MBR when viewing the new ISCSI device. Only when I hade told windows (via disk management) to use GPT could I format the whole 8Tb volume.

BoX

[OverWorked]

Thanks everyone. I found it. It was the MBR limit, not iSCSI.

I have two of these NAS boxes. During setting up the second one I saw the dialog in disk management giving the chice of MBR or GPT when I initialized the disk. The dialog describes the 2TB MBR limit.