2.4TB disk - MBR and GPT coexist?

Thu Jan 11 14:02:37 UTC 2007

On Thursday, 11 January 2007 at  1:04:10 -0800, Jo Rhett wrote:
> So I have a raid array of 2.4TB.  And yes, I really need 2.4TB, and no 
> there's no room for another set of disks to boot from.
> /    1g
> /var 16g
> /big **everything else
> 
> Sysinstall recognized the drive properly and everything looked dandy 
> during install.  However, it turns out that fdisk and bsdlabel both just 
> chopped off the last partition at 248GB.  (why 248gb and not 2tb?)
> 
> Reading the various mailing lists, it strikes me that I need to make 
> partition 1 be normal MBR, and then use GPT to create another partition 
> table in slice 2.  Makes sense to me.

You need to create two arrays first, for example here is my ARECA
configuration:

Here is drives on my server:
CLI> disk info
Ch   ModelName        Serial#          FirmRev     Capacity  State
===============================================================================
 1   WDC WD3200YS-01  WD-WCAPD2905423  21.00M21     320.1GB  RaidSet Member(1)
 2   WDC WD3200YS-01  WD-WCAPD2784014  21.00M21     320.1GB  RaidSet Member(1)
 3   WDC WD3200YS-01  WD-WCAPD2938741  21.00M21     320.1GB  RaidSet Member(1)
 4   WDC WD3200YS-01  WD-WCAPD2905454  21.00M21     320.1GB  RaidSet Member(1)
 5   WDC WD3200YS-01  WD-WCAPD2909622  21.00M21     320.1GB  RaidSet Member(1)
 6   WDC WD3200YS-01  WD-WCAPD2941988  21.00M21     320.1GB  RaidSet Member(1)
 7   WDC WD3200YS-01  WD-WCAPD2895051  21.00M21     320.1GB  RaidSet Member(1)
 8   WDC WD3200YS-01  WD-WCAPD2840974  21.00M21     320.1GB  RaidSet Member(1)
 9   WDC WD3200YS-01  WD-WCAPD2908560  21.00M21     320.1GB  RaidSet Member(1)
10   WDC WD3200YS-01  WD-WCAPD2908273  21.00M21     320.1GB  RaidSet Member(1)
11   WDC WD3200YS-01  WD-WCAPD2694369  21.00M21     320.1GB  RaidSet Member(1)
12   WDC WD3200YS-01  WD-WCAPD2941968  21.00M21     320.1GB  RaidSet Member(1)
13   WDC WD3200YS-01  WD-WCAPD2908270  21.00M21     320.1GB  RaidSet Member(1)
14   WDC WD3200YS-01  WD-WCAPD2675053  21.00M21     320.1GB  RaidSet Member(1)
15   WDC WD3200YS-01  WD-WCAPD2804241  21.00M21     320.1GB  RaidSet Member(1)
16   WDC WD3200YS-01  WD-WCAPD2908119  21.00M21     320.1GB  RaidSet Member(1)
===============================================================================
GuiErrMsg<0x00>: Success.

And here is two arrays:
CLI> vsf info
 # Name             Raid# Level   Capacity Ch/Id/Lun  State
===============================================================================
 1 ARC-1160-VOL#00    1   Raid5     25.0GB 00/00/00   Normal
 2 ARC-1160-VOL#01    1   Raid5   4775.0GB 00/00/01   Normal
===============================================================================
GuiErrMsg<0x00>: Success.

The first one contain normal MBR record:

# fdisk /dev/da0
******* Working on device /dev/da0 *******
parameters extracted from in-core disklabel are:
cylinders=3039 heads=255 sectors/track=63 (16065 blks/cyl)

Figures below won't work with BIOS for partitions not in cyl 1
parameters to be used for BIOS calculations are:
cylinders=3039 heads=255 sectors/track=63 (16065 blks/cyl)

Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
    start 63, size 48821472 (23838 Meg), flag 80 (active)
        beg: cyl 0/ head 1/ sector 1;
        end: cyl 1023/ head 254/ sector 63
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
<UNUSED>
The data for partition 4 is:
<UNUSED>

And here is the mount points on this array:

/dev/da0s1a on / (ufs, local)
/dev/da0s1d on /tmp (ufs, local, noatime, nosuid, soft-updates)
/dev/da0s1f on /usr (ufs, local, soft-updates)
/dev/da0s1e on /var (ufs, local, soft-updates)

The second array contain GPT record created with gpt utility:

# fdisk /dev/da1
******* Working on device /dev/da1 *******
parameters extracted from in-core disklabel are:
cylinders=580527 heads=255 sectors/track=63 (16065 blks/cyl)

Figures below won't work with BIOS for partitions not in cyl 1
parameters to be used for BIOS calculations are:
cylinders=580527 heads=255 sectors/track=63 (16065 blks/cyl)

Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
sysid 238 (0xee),(EFI GPT)
    start 1, size 4294967295 (2097151 Meg), flag 0
        beg: cyl 1023/ head 255/ sector 63;
        end: cyl 1023/ head 255/ sector 63
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
<UNUSED>
The data for partition 4 is:
<UNUSED>

Mount point:

/dev/da1p1 on /mnt/mnt2 (ufs, local, noatime, soft-updates)

> 
> How?  In theory this seems simple, but I can't figure out how to modify 
> the slices without fdisk, which won't play ball with the larger size.
> 
> And why 248GB anyway?  I'd almost be willing to lose the extra .4tb if 
> it just stopped at 2TB.  Why does it slap back down to 248gb?
> 
> NOTE: yes I already understand about PC BIOS and MBR, and not reading 
> GPT format.  The question is -- how do I make them coexist?
> 
> -- 
> Jo Rhett
> senior geek
> Silicon Valley Colocation
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-- 
======================================================================  
- Best regards, Nikolay Pavlov. <<<-----------------------------------    
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