# Important note for accessing >2TB drives

## nuclearcat

http://www.coraid.com/support/linux/contrib/chernow/gpt.html

I want to quote following:

[pre]

After learning the hard way, which is what testing is for, I found you must have GPT support on in the kernel. This in under:

File Systems

   Partition Types

     [*] Advanced partition selection

     [*] EFI GUID Partition support (NEW)

These must be on! EFI GUID sets the "CONFIG_EFI_PARTITION" flag. The help menu states: 

Say Y here if you would like to use hard disks under Linux which were partitioned using EFI GPT. Presently only useful on the IA-64 platform.

The last line is outdated, "Presently" is no longer true. We have it working on a 2.6.14 Intel 32-bit.

Without this on, strange things happen. For instance, rebooting the machine caused the file system to no longer be mountable or the GPT table got corrupted. Nice thing about GPT is that is keeps a backup table at the end of the disk.

When you turn GPT support on, everything works as expected. All problems went away. We could no longer break it.

[/pre]

And i see on forum many people face this issue. Maybe it is good to put in manuals and FAQ, cause without following this rule it is causing data loss. And usually on >2TB it is difficult to recover data. And already i face that issue.

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## madcow3891

... This was the secret I had been looking for. All issues resolved with our MD1000 7TB array. THANK YOU.   :Very Happy: 

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