View source for Very Large Hard Drive

__NOTOC__

{{Warning|title=Work in progress|This page is a work-in-progress describing the process necessary to install a very large hard drive into a Humax HDR Fox T2.}}

With the release of Custom Firmware 3.10 it is now possible to fit a Humax HDR Fox T2 with a hard drive having more than 2^32 sectors. In practice this means that drives between 2TB and 4TB in size can now be used. Disks larger than 4TB have been found to cause problems with the Humax software reporting low amounts of free space.

===Drives known to work===

The following very large drives have been successfully tested:

{| class=wikitable
! AV? || Vendor || Description || Model || Size || Cache || RPM || Physical Sector || Logical Sector
|-
| * || Seagate || Video 3.5" HDD SATA || ST4000VM000 || 4TB || 64MB || 5900 || 4096 || 512
|-
|   || Seagate || NAS 3.5" HDD SATA || ST4000VN000 || 4TB || 64MB || 5900 || 4096 || 512
|-
|   || Western Digital || Green.. TBC || || 4TB
|}

{{Note|'''Always choose a specific Audio/Visual (AV) or Digital Video Recorder (DVR) drive if possible.'''

* Avoid drives which are designed for RAID use (e.g. WD Red and Purple drives) as they will have TLER (an error recovery option) enabled which can cause issues if there are problems with reading or writing to a sector. AV drives usually have this parameter disabled so that a failed write is just ignored and recording moves on. It can also cause complications when dealing with any problem sectors in the future as it causes some issues to be hidden from the host (the Humax in this scenario).
* WD Purple drives have a surprisingly low workload rating of 60TB/year and should be avoided.
* With any non-AV Western Digital disk, watch the disk stats to check if the load/unload count grows quickly which could indicate that automatic head parking after 8 seconds is enabled. This can (and should) be disabled using ''wdidle3''[http://www.storagereview.com/how_to_stop_excessive_load_cycles_on_the_western_digital_2tb_caviar_green_wd20ears_with_wdidle3]. }}

===Pre-requisites===

Using a very large drive requires Custom Firmware 3.10 or above. The stock Humax firmware cannot read these drives at all (it will see them but consider them to have a zero size).

===Partitions tables===

With these large drives, it is necessary to use a partitioning scheme called GUID Partition Table (GPT). When using a GPT, a legacy MBR containing a partition table is also created on the drive. This MBR generally contains a single partition of type ''EFI GPT'' (code 0xee) encompassing the entire drive, well as much of the drive as can be represented in an MBR partition - 2^32 sectors. This is known as a ''protective MBR'' since its main purposes is to prevent non-GPT-aware systems and tools from viewing the drive as empty or available. In the case of the Humax, it is necessary to create three partitions on the drive so that the Humax software sees these and considers the drive to be properly formatted.

===Creating the GPT and formatting the disk===

Restart the Humax into Maintenance mode then use the telnet menu to do the work for you. Just choose the ''gptf'' option and confirm that you really want to reformat the disk.

 Menu version 1.20
 Enter system PIN: ****
 
       /---------------------------------------------\
       |  M A I N T E N A N C E   M O D E   M E N U  |
       \---------------------------------------------/
 
   [ Humax HDR-Fox T2 (gpttest) 1.03.12/3.10 ]
 
   Note: Some areas of the hard disk are not mounted.
         Not all functions will be available.
         (normal if you have just run a disk check)
 
     1 - Check and repair hard disk (fix-disk).
     2 - Run short hard-disk self test.
     3 - Run long hard-disk self test.
     4 - Check self-test progress.
  gptf - Re-format disk using GPT scheme.
   epg - Clear persistent EPG data.
  dlna - Reset DLNA server database.
     x - Leave maintenance mode (Humax will restart).
  diag - Run a diagnostic.
   cli - System command line (advanced users).
 
 Please select option: gptf
 
 This process will format the internal hard disk using the GUID partitioning
 scheme (GPT) which supports hard disks over 2TB in size.
 
 ****************************************************************
 *** All data on the hard drive will be erased if you proceed ***
 ****************************************************************
 
 Are you sure you wish to format and erase the disk? [Y/N] y
 Are you sure you wish to do this? [Y/N] y
 Are you sure you wish to COMPLETELY ERASE this hard disk? [Y/N] y
 
 **********************************************************************
 * Unmounting partitions...
 **********************************************************************
 
 **********************************************************************
 * Clearing all existing partition tables...
 **********************************************************************
 
 Creating new GPT entries.
 GPT data structures destroyed! You may now partition the disk using fdisk or
 other utilities.
 
 **********************************************************************
 * Creating GUID partition table (GPT)...
 **********************************************************************
 
 Creating new GPT entries.
 The operation has completed successfully.
 
 **********************************************************************
 * Creating MBR partition table...
 **********************************************************************
 
 >>> /dev/sda2: /dev/sda3: /dev/sda4:
 
 **********************************************************************
 * Final MBR table...
 **********************************************************************
 
 Disk /dev/sda: 465.8 GiB, 500107862016 bytes, 976773168 sectors
 Units: sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes
 Disklabel type: dos
 Disk identifier: 0x0c82049c
 
 Device     Boot   Start     End Sectors  Size Id Type
 /dev/sda1             1 2097151 2097151 1024M ee GPT
 /dev/sda2       2097152 4194303 2097152    1G 83 Linux
 /dev/sda3       4194304 6291455 2097152    1G 83 Linux
 
 **********************************************************************
 * Final GPT table...
 **********************************************************************
 
 Disk /dev/sda: 465.8 GiB, 500107862016 bytes, 976773168 sectors
 Units: sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes
 Disklabel type: gpt
 Disk identifier: 372B3BA4-7C50-4D29-8551-4A94E7826C05
 
 Device         Start       End   Sectors   Size Type
 /dev/sda1       2048   2099199   2097152     1G Linux filesystem
 /dev/sda2    2099200 955801614 953702415 454.8G Linux filesystem
 /dev/sda3  955803648 976773134  20969487    10G Linux filesystem
 
 **********************************************************************
 * Formatting partition 1...
 **********************************************************************
 
 mke2fs 1.42.10 (18-May-2014)
 Creating filesystem with 262144 4k blocks and 65536 inodes
 Filesystem UUID: a442c849-f26e-4dd0-b1fe-cef4cf8416b5
 Superblock backups stored on blocks:
         32768, 98304, 163840, 229376
 
 Allocating group tables: done
 Writing inode tables: done
 Creating journal (8192 blocks): done
 Writing superblocks and filesystem accounting information: done
 
 .... continues to format partitions 2 & 3 ...