{"id":366,"date":"2009-05-08T13:21:02","date_gmt":"2009-05-08T03:51:02","guid":{"rendered":"http:\/\/www.clearchain.com\/blog\/?p=366"},"modified":"2011-05-04T16:44:26","modified_gmt":"2011-05-04T07:14:26","slug":"booting-freebsd-from-a-root-zfs-pool-using-a-standard-mbr-and-partition-table","status":"publish","type":"post","link":"https:\/\/www.clearchain.com\/blog\/posts\/booting-freebsd-from-a-root-zfs-pool-using-a-standard-mbr-and-partition-table","title":{"rendered":"Booting FreeBSD from a root zfs pool using a standard MBR and partition table"},"content":{"rendered":"

This page documents the current state of play for booting the root filesystem (\/) off a zfs zpool under FreeBSD, using a standard master boot record (MBR) and a standard partition table. The aim was to be able to have a dual boot system for my laptop using the standard FreeBSD quick selection boot loader.<\/p>\n

Note, this does not cover using the gpt based partition tables. If you want to use these, please refer to the following page: <\/span>http:\/\/lulf.geeknest.org\/blog\/freebsd\/Setting_up_a_zfs-only_system\/<\/a> or booting zfs as root using a small ufs boot partition as provided by the instructions at:\u00a0http:\/\/wiki.freebsd.org\/ZFSOnRoot.
\n<\/a><\/span><\/p>\n

Below is the steps required to be able to setup the root zpool<\/p>\n

    \n
  1. Download a FreeBSD -current fixit cdrom snapshot later than 200901, as these have loader ZFS support<\/li>\n
  2. Burn the CD<\/li>\n
  3. Boot the CD<\/li>\n
  4. Setup any partitions you want – note you must setup the ‘a’ partition to cover the entire device as the loader will use this.<\/span><\/li>\n
  5. Select Fixit from the menu, and use the CDrom as a source<\/li>\n
  6. Create the pool and install the loader (see below)<\/li>\n
  7. Copy the required files to boot (see below)<\/li>\n<\/ol>\n

    Creating the root zpool and installing the Loader<\/h2>\n

    The fixit cd has everything required to create a zpool, however by default none of the required modules are loaded. Hence they need to be loaded first:<\/p>\n

    cd \/mnt2\/boot\/kernel\r\nkldload .\/opensolaris.ko\r\n\r\nkldload .\/zfs.ko<\/span><\/span><\/span><\/span><\/span><\/pre>\n
    Once the modules have been loaded all the zfs tools (zpool,zfs,zdb) should now work. Let assume you want to install FreeBSD to \/dev\/ad4s2 (second partition on a sata disk). You can do this using:<\/p>\n
        zpool create somename<\/em><\/strong> \/dev\/ad4s2<\/pre>\n
    Where somename<\/span> is the name of the pool you want to create. This creates a single zfs filesystem and a zfs pool of storage. To install the boot loader you need to do:<\/p>\n
        # dd if=\/mnt2\/boot\/zfsboot of=\/dev\/da0s1 count=1\r\n    # dd if=\/mnt2\/boot\/zfsboot of=\/dev\/da0s1 skip=1 seek=1024<\/pre>\n
    The first line installs boot1, the second line installs boot2. \u00a0However, boot2 is responsible for loading boot3 (aka the loader – found in \/boot\/loader). Hence that must be put in place.<\/p>\n
    Copying the required files to boot<\/h2>\n
    The easiest way to get things to the point where things are ready to boot is to copy all the files from \/dist \u00a0– the live distribution. Before you do this, you might like to take advantage of zfs and create some subfilesystems so you can snapshot, monitor space, etc.<\/p>\n
    For instance creating a \/usr and \/var filesystem is often very handy:<\/p>\n
    \u00a0\u00a0 \u00a0#zfs create somename\/usr\r\n    #zfs create somename\/var<\/pre>\n
    Now you can copy the base system:<\/p>\n
     \u00a0 \u00a0cp -a \/dist\/* \/somename<\/pre>\n
    This will install among other things:<\/p>\n