Difference between revisions of "Disk partitioning miscellanea"
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For '''<code>grub</code>''' to boot a non-EFI machine from an GPT-partitioned disk, leave a gap between sector 0 and the first partition. Starting the first partition at sector 2048 accomplishes this nicely. |
For '''<code>grub</code>''' to boot a non-EFI machine from an GPT-partitioned disk, leave a gap between sector 0 and the first partition. Starting the first partition at sector 2048 accomplishes this nicely. |
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| − | EFI machines will |
+ | EFI machines will need an EFI boot partition, too. A bit annoying, but it doesn't hurt to skip it on the |
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| + | == boot mirror creation == |
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| + | This is how van-van-mojo's boot mirror looks: |
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| + | '''<code>/dev/sda1</code>''' (and the other boot mirror member devices) starts at sector 2048, leaving a 1Mibyte gap before it (them) and the start of the disk. |
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| + | '''<code>/dev/sda1</code>''' is 2099224 sectors long. Which is 1Gibyte for data plus 1036kibytes for software RAID metadata and overhead. |
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| + | '''<code>mdadm --create md_boot --verbose --metadata=1.2 --chunk=64 --level=1 --raid-devices=6 --name md_boot /dev/sda1 missing missing missing missing missing</code>''' |
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== MD software RAID offsets == |
== MD software RAID offsets == |
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Latest revision as of 22:06, 12 July 2012
GPT is cool
For grub to boot a non-EFI machine from an GPT-partitioned disk, leave a gap between sector 0 and the first partition. Starting the first partition at sector 2048 accomplishes this nicely.
EFI machines will need an EFI boot partition, too. A bit annoying, but it doesn't hurt to skip it on the
boot mirror creation
This is how van-van-mojo's boot mirror looks:
/dev/sda1 (and the other boot mirror member devices) starts at sector 2048, leaving a 1Mibyte gap before it (them) and the start of the disk.
/dev/sda1 is 2099224 sectors long. Which is 1Gibyte for data plus 1036kibytes for software RAID metadata and overhead.
mdadm --create md_boot --verbose --metadata=1.2 --chunk=64 --level=1 --raid-devices=6 --name md_boot /dev/sda1 missing missing missing missing missing
MD software RAID offsets
12kibytes are used by the MD metadata. If you want a RAID-1 MD device with a capacity of 1Gibyte, create the partitions with 2097176 sectors.