preseed-fragment.seed

d-i   partman-auto/disk string /dev/sda

# Use LVM for partitioning
d-i   partman-auto/method string lvm

# If one of the disks that are going to be automatically partitioned
# contains an old LVM configuration, the user will normally receive a
# warning. Preseed this away
d-i     partman-lvm/device_remove_lvm boolean true

# And the same goes for the confirmation to write the lvm partitions.
d-i     partman-lvm/confirm boolean true

# Really, please don't prompt me!
d-i     partman-lvm/confirm_nooverwrite boolean true

#  partitioning
# Physical partitions:
# 1. BIOS boot partition: 1 MB See https://wiki.archlinux.org/index.php/GRUB2#GUID_Partition_Table_.28GPT.29_specific_instructions
# 2. Boot partition: 250 MB
# 2. LVM, with the following logical volumes
#     - Root partition: 250 GB (256000 MB), ext4.
#     - Swap: 100% of RAM
#     - Data partition: remaining space, XFS
d-i partman-auto/expert_recipe string                         \
      boot-root ::                                            \
              1 1 1 free method{ biosgrub } .                 \
              250 250 250 ext2                                \
                      $primary{ } $bootable{ }                \
                      method{ format } format{ }              \
                      use_filesystem{ } filesystem{ ext2 }    \
                      mountpoint{ /boot }                     \
              .                                               \
              100% 2048 100% linux-swap                       \
                      lv_name{ swap }                         \
                      method{ swap } format{ }                \
                      $lvmok{ }                               \
              .                                               \
              256000 256000 256000 ext4                       \
                      lv_name{ root }                         \
                      method{ lvm } format{ }                 \
                      use_filesystem{ } filesystem{ ext4 }    \
                      mountpoint{ / }                         \
                      $lvmok{ }                               \
              .                                               \
              1024 1024 -1 xfs                                \
                      lv_name{ data }                         \
                      method{ lvm } format{ }                 \
                      use_filesystem{ } filesystem{ xfs }     \
                      mountpoint{ /data }                     \
                      $lvmok{ }                               \
              .

# This makes partman automatically partition without confirmation, provided
# that you told it what to do using one of the methods above.
d-i     partman-partitioning/confirm_write_new_label boolean true
d-i     partman/choose_partition select finish
d-i     partman/confirm boolean true
d-i     partman/confirm_nooverwrite boolean true



======================
d-i partman-auto/expert_recipe string physics-workstation :: \
              32 32 32 free                                  \
                      $gptonly{ }                            \
                      $primary{ }                            \
                      $bios_boot{ }                          \
                      method{ biosgrub }                     \
              .                                              \
              1600 1000 1600   linux-swap                    \
                      $gptonly{ }                            \
                      $primary{ }                            \
                      method{ swap } format{ }               \
              .                                              \
              25500 9000 25555 xfs                           \
                      $gptonly{ }                            \
                      $primary{ }                            \
                      method{ format } format{ }             \
                      use_filesystem{ } filesystem{ xfs }    \
                      mountpoint{ / }                        \
              .                        

and the output:
# gdisk -l /dev/vda
GPT fdisk (gdisk) version 0.8.4

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.
Disk /dev/vda: 335544320 sectors, 160.0 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 2A256643-D59F-4B71-B796-9137E7241FE9
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 335544286
Partitions will be aligned on 1-sector boundaries
Total free space is 0 sectors (0 bytes)

Number  Start (sector)    End (sector)  Size       Code  Name
   1              34           62534   30.5 MiB    EF02  
   2           62535         3187535   1.5 GiB     8200  
   3         3187536        52992223   23.7 GiB    0700 


====================
d-i preseed/late_command string echo ';' | sfdisk /dev/sdb ; xfs-format ;
    echo '/dev/sdb1 none xfs sw 0 0' >> /target/etc/fstab ;
    echo ';' | sfdisk /dev/xvdb ; mke2fs -j -q /dev/xvdb1 ;
    mkdir /target/var/build ;
    echo '/dev/xvdb1 /var/build ext3 defaults 0 2' >> /target/etc/fstab

==========================
d-i apt-setup/non-free boolean true
d-i apt-setup/contrib boolean true

d-i pkgsel/include string \
    openssh-server build-essential lsof \
    mlocate
d-i pkgsel/upgrade select full-upgrade

d-i preseed/late_command string \
    in-target wget http://debian.orionschools.us/ohs-postpreseed.sh; \
    in-target /bin/bash -x chmod 755 ./ohs-postpreseed.sh; \
    in-target /bin/bash -x ./ohs-postpreseed.sh;