Monday, November 2, 2009

Maximum Size Apple Partition Map

Got a super Seagent FreeAgent Pro eSata / Firewire / USB hard drive. Comes a funky module to switch from eSata / USB to dual Firewire 400.

Anyway, it also comes formatted NTFS, which is no good, so I reformatted as HFS+ Extended / Journalled.

So I fired up Disk Utility, and reformatted the drive. Well it failed. Weird. Here's the log:

2009-10-27 19:39:47 +0000: Preparing to erase : “Untitled”
2009-10-27 19:39:47 +0000: Partition Scheme: Master Boot Record
2009-10-27 19:39:47 +0000: 1 volume will be created
2009-10-27 19:39:47 +0000: Name : “Untitled”
2009-10-27 19:39:47 +0000: Size : 698.6 GB
2009-10-27 19:39:47 +0000: Filesystem : Mac OS Extended (Journaled)

2009-10-27 19:39:47 +0000: Creating partition map.
2009-10-27 19:39:49 +0000: Formatting disk3s1 as Mac OS Extended (Journaled) with name Untitled.
2009-10-27 19:39:50 +0000: Disk Erase failed with the error:

File system formatter failed.
2009-10-27 19:39:51 +0000: Erase complete.
2009-10-27 19:39:51 +0000:
2009-10-27 19:39:51 +0000: Disk Utility failed during an unspecified action with the error:

File system formatter failed.
2009-10-27 19:39:51 +0000: Erase complete.
2009-10-27 19:39:51 +0000:
2009-10-27 19:39:52 +0000: Erase complete.
2009-10-27 19:39:52 +0000:

After a bit of Googling, seems that the new 750Gb drive is too big to be formatted as Apple Partition Map. My slightly older 640Gb is OK with Apple Partition Map:


The answer is to format as GUID. In Disk Utility, click on Partition and then select one partition:


Click Options, and select GUID:


after the format, you can see the difference:


The curious thing is that Apple Partition Map supports bigger partition sizes, I think.

PS The drive is GREAT!

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