Arch Linux

JamieKitson

Member

From: UK

Registered: 2010-10-18

Posts: 161

Website

GPT Conversion and Auto-Alignment

Hi,

just wondering if I convert an msdos partition table and MBR to GPT whether the partitions will now be auto aligned? I have a new SSD and stupidly read the Arch SSD article after I'd already formatted the drive and copied over my installation. I have now run gdisk and converted to GPT and wonder if that is enough. If not, what do I need to do now?

Cheers, Jamie

https://wiki.archlinux.org/index.php/So … DED_METHOD

skodabenz

Banned

From: Tamilnadu, India

Registered: 2010-04-11

Posts: 382

Re: GPT Conversion and Auto-Alignment

Hi,

just wondering if I convert an msdos partition table and MBR to GPT whether the partitions will now be auto aligned? I have a new SSD and stupidly read the Arch SSD article after I'd already formatted the drive and copied over my installation. I have now run gdisk and converted to GPT and wonder if that is enough. If not, what do I need to do now?

Cheers, Jamie

https://wiki.archlinux.org/index.php/So … DED_METHOD

Converting from MBR to GPT using gdisk will not do any automatic alignment. The partition start and end sector numbers in the table are not modified by gdisk during conversion ( http://rodsbooks.com/gdisk/mbr2gpt.html ). The conversion is like you manually note down the partition sector numbers from fdisk in MBR table. Erase the table and then add partitions using gdisk with sector numbers obtained from fdisk.

However if you initialize a new GPT table from gdisk, then it will take care of automatic 1 MB alignment.

---

My new forum user/nick name is "the.ridikulus.rat" .

JamieKitson

Member

From: UK

Registered: 2010-10-18

Posts: 161

Website

Re: GPT Conversion and Auto-Alignment

Thanks. One way or another though my partitions are aligned:

Command (? for help): p
Disk /dev/sda: 117231408 sectors, 55.9 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): A611061B-12BB-4880-91B7-BBE7601BB674
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 117231374
Partitions will be aligned on 2048-sector boundaries
Total free space is 83693 sectors (40.9 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048       106991615   51.0 GiB    0700  Linux/Windows data
   2       106991616       117147647   4.8 GiB     8200  Linux swap
   3       117227520       117229567   1024.0 KiB  EF02  

Last edited by JamieKitson (2011-01-15 10:47:24)