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Re: Free space in partman

Łukasz Stelmach <steelman@post.pl> writes:

> Hi,
> I am trying to figure out where is the code that makes partman (fed
> with a custom recipe) leave 1MB of free space at the beginning of the
> disk? Is it possible to control the size of that space?

That's the result of default partition alignment.

Here's the text from the gdisk man page about the 'l' command that lets
you change that (and hints at why you don't want to ;-) ):

  l  Change the sector alignment value. Disks with more logical sectors
     per physical sectors (such as modern Advanced Format drives), some
     RAID configurations, and many SSD devices, can suffer performance
     prob‐ lems if partitions are not aligned properly for their
     internal data structures. On new disks, GPT fdisk attempts to align
     partitions on 1MiB boundaries (2048-sectors on disks with 512-byte
     sectors) by default, which optimizes performance for all of these
     disk types. On pre-partitioned disks, GPT fdisk attempts to
     identify the alignment value used on that disk, but will set
     8-sector alignment on disks larger than 300 GB even if lesser
     alignment values are detected. In either case, it can be changed by
     using this option.

Cheers, Phil.
|)|  Philip Hands  [+44 (0)20 8530 9560]  HANDS.COM Ltd.
|-|  http://www.hands.com/    http://ftp.uk.debian.org/
|(|  Hugo-Klemm-Strasse 34,   21075 Hamburg,    GERMANY

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