Beefy Boxes and Bandwidth Generously Provided by pair Networks
go ahead... be a heretic

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??

I concur with rhesa's method. I've used this before with considerable success.

I just untarred a test structure containing a million files distributed this way using 3 levels of subdirectory to give an average of ~250 file per directory. I then ran a quick test of opening and reading 10,000 files at random and got an average time to locate, open, read and close each file of 12ms.

#! perl -slw use strict; use Math::Random::MT qw[ rand ]; use Digest::MD5 qw[ md5_hex ]; use Benchmark::Timer; our $SAMPLE ||= 1000; my $T = new Benchmark::Timer; for my $i ( 1 .. $SAMPLE ) { $T->start( 'encode/open/read/close' ); my $md5 = md5_hex( int( rand 1e6 ) ); my( $a, $b, $c ) = unpack 'AAA', $md5 ; $T->start( 'open' ); open my $fh, '<', "fs/$a/$b/$c/$md5.dat" or warn "fs/$a/$b/$c/$md5 + : $!"; $T->stop( 'open' ); $T->start( 'read' ); my $data = do{ local $/; <$fh> }; $T->stop( 'read' ); $T->start( 'close' ); close $fh; $T->stop( 'close' ); $T->stop( 'encode/open/read/close' ); } $T->report; __END__ c:\test>612729-r -SAMPLE=10000 10000 trials of encode/open/read/close (112.397s total), 11.240ms/tria +l 10000 trials of open (110.562s total), 11.056ms/trial 10000 trials of read (158.554ms total), 15us/trial 10000 trials of close (365.520ms total), 36us/trial

The files in this case are all 4k, but that doesn't affect your seek time. If you envisage needing to deal with much more than 1 million files, moving to 4 levels of hierarchy woudl distribute the million files at just 15 per directory.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re^3: Perl solution for storage of large number of small files by BrowserUk
in thread Perl solution for storage of large number of small files by isync

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

  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or or How to display code and escape characters are good places to start.
Log In?

What's my password?
Create A New User
Domain Nodelet?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others surveying the Monastery: (3)
As of 2022-08-08 10:18 GMT
Find Nodes?
    Voting Booth?

    No recent polls found