Sometimes a useful trick is to change the input line separator ($/ - perlvar). Consider:

use strict;
use warnings;

local $/ = 'Pseudo name=';

/^(\w*).*?Logical device ID=(\w*)/s and print "$1, $2\n" while <DATA>;

__DATA__
Pseudo name=hdiskpower97
Symmetrix ID=000187751303
...
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given all the samples data prints:

hdiskpower97, 0380
hdiskpower90, 0381
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