Netgate Discussion Forum
    • Categories
    • Recent
    • Tags
    • Popular
    • Users
    • Search
    • Register
    • Login

    Block Size When Installing to Compact Flash

    Scheduled Pinned Locked Moved Problems Installing or Upgrading pfSense Software
    4 Posts 4 Posters 3.7k Views
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • C
      cyboc
      last edited by

      Page 34 of the pfSense Book talks about installing pfSense onto a compact flash card using the dd command. I noticed that the example invocations of dd use block sizes of 16k, 64k and 16k for Linux, FreeBSD and Mac OS X, respectively.

      That begs these questions:

      • Why were those block sizes chosen?

      • Why is the FreeBSD block size bigger than Linux and Mac OS X?

      • What would happen if other block sizes (e.g. 4k) were used?

      I'm just curious.

      1 Reply Last reply Reply Quote 0
      • E
        EddieA
        last edited by

        I'm not sure why the difference, but all that parameter does, is control how much data is read/written at a time.  You could substitute any value, and it would still work.

        Cheers.

        1 Reply Last reply Reply Quote 0
        • W
          wallabybob
          last edited by

          but larger block sizes give higher transfer rates, significantly reducing the time it takes to write the target disk.

          1 Reply Last reply Reply Quote 0
          • C
            cmb
            last edited by

            The instructions were just gathered/added from various sources over time, indeed the block size isn't relevant aside from performance. That's the first I've noticed that actually. We'll clean that up.

            1 Reply Last reply Reply Quote 0
            • First post
              Last post
            Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.