Your priority values are hashes. So how do you want to compare {'IS-ABC' => '3'} with {'IS-XYZ' => '3'}? Do you compare IS-ABC with IS-XYZ alphabetically, and what if they are equal?

From your desired output here's something that I think will work: 

sub sortBySite {
        my ($site_a) = keys %{$tmp{$a}{'priority'}};
        my ($site_b) = keys %{$tmp{$b}{'priority'}};
        return $site_a cmp $site_b;
}

[download]

Also, does your data really need to be stored as a HoH? Would this simpler structure work for you? 

  'hostX1-1-l.example.com' => {
    priority => 'IS-ABC',
    priority_level => 3,
    os => 'linux',
    pager => 'man-duty',
  }

[download]

In reply to Re: Sorting HoH on 2nd level key? by pc88mxer
in thread Sorting HoH on 2nd level key? by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.