Installing a Drive Larger Than 2TB - Possible?

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Hello all.
It's been a while since THIS THREAD was active.... so for me it's time to revive it 3 years later!

- having just read this topic today, does it now mean (with the use of this wonderful guide), i can format, and subsequently install any storage size HDD as a replacement for the internal 500GB? - Or is there still a limit of HDD size being 2TB max (as per original thread) ??

(i appreciate the physical size of the HDD must be considered, but i'm talking about Data/Storage size.
After 3 years, HDD's have massively increased in capacity!)

thanks

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Luke

Well-Knwοn Мember
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- having just read this topic today, does it now mean (with the use of this wonderful guide), i can format, and subsequently install any storage size HDD as a replacement for the internal 500GB? - Or is there still a limit of HDD size being 2TB max (as per original thread) ??
Or if you are on 1.03.12 software just slip in a 2TB drive and get the Humax to format it. If you are on1.03.06 or 1.03.11 that'll be OK as well.

One of my HDR-FOX T2s is on 1.2.20 and I just temporarily updated it to 1.03.12 to format the drive and then rolled back.
 
OP
Des in London

Des in London

Member
does it now mean (with the use of this wonderful guide), i can format, and subsequently install any storage size HDD as a replacement for the internal 500GB?
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Hi Luke thanks for the reply.
My wording may have confused you a little (my apologies), you are assuming i want to follow this guide exactly with a 2TB - my question was more general in that HDD's overall have increased in capacity over the years, so are we users still limited to a 2TB HDD because of other limiting conditions (for example) on the Humax box, or not?

I'm on the latest revision and have CF installed so i already know that the box can format up to 2TB - but what about a larger size?

Thanks in advance :)

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Trev

The Dumb One
Do you mean "Can I use a disk larger than 2TB in my T2 if I format it by some other means?"? I don't know the answer, but somebody might.
EDIT. Seems like somebody just did.
 

Black Hole

May contain traces of nut
There are (highly experimental) possibilities of going up to 16TB, as explained in the reference, but these are not for the faint-hearted.
 

Black Hole

May contain traces of nut
Some of the discussion re OS support for MBR and the possibility of formatting with large sectors/clusters still applies. Obviously a translating USB-SATA adapter is not relevant.
 
OP
Des in London

Des in London

Member
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I never thought asking such a simple question would be so difficult!
(tongue-in-cheek ;) )

I will say that though, my understand of this Forum (coming from a newbie perspective) was to encourage, and to push each other to perform such difficult tasks and carry out non-standard actions, such as creating the custom firmware for example. So manually formatting/partitioning an "Advanced Format" (4K native) Hard Disk to be used inside or outside of the Box shouldn't be rocket science (from my perspective of course).

To that end, the "2TB Disk Installation Blog" (bloody fabulous by the way!) comes across as YOU CAN install ANY CAPACITY Hard Drive (for internal or external use), so long as you partition with the following conditions:
(...extracted from the 'blog' for those who aren't aware of it....):

The solution is to align your operating system file-system block size with the native sector size of the disk and to ensure that the partitions on the disk are aligned with the 4K sectors. The following diagram illustrates this




The first part is easy - ext3 has a default block size of 4096 bytes so maps nicely onto a 4K disk sector. However, just using a 4K file-system block size isn't enough. In the diagram above, file-system block A is not aligned with a disk sector so when block A is changed sectors X and Y must be updated using a read-modify-write sequence including an additional platter rotation. The complete solution requires that partitions are aligned with disk sectors

So unless i'm completely stupid and i managed to read something that isn't true (for which i apologies to all those who were steering me away from this task) - i should be able to (manually) format a 6TB HDD for internal or external use, correct? Better still, i should be able to buy the new "Seagate 8TB HDD" and use it for archiving (once manually formatted/partitioned to EXT3) ??

Thanks again in advance.
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Black Hole

May contain traces of nut
As far as I know, there is no reason you could not create a specially formatted HDD (for internal use) that exceeds the nominal 2TB - by using larger clusters. That will at least bypass the limitations of the MBR, although I have no idea whether the Humax firmware is able to cope with the file system statistics that would result. However, as far as I know, nobody has ever reported having done this and you would be trail blazing.

The original motivation behind the 2TB installation blog is that at one time the Humax firmware would refuse to format HDDs over 500GB in capacity. Once a firmware update provided formatting for HDDs up to the nominal maximum for the MBR (with normal 512byte cluster size), there was no longer any need to go to that amount of trouble - just install a new HDD and let it rip. But the blog provides the information as to what is required, and an intrepid person wanting to extend that beyond 2TB has a starting point.

No discouragement is intended. What I seek to do is make sure you are aware of current knowledge, and ensure you are aware of the likely difficulty of the project. If you succeed and report how you did it, you will be extending the knowledge base. Carry on in the spirit of exploration by all means, but do consider first whether it is worth the effort. Even a 500GB HDD only fills up because of bad housekeeping - stuff regarded as valuable to keep would be better archived off to USB drives (in duplicate).
 

MartinLiddle

Super Moderator
Staff member
.So unless i'm completely stupid and i managed to read something that isn't true (for which i apologies to all those who were steering me away from this task) - i should be able to (manually) format a 6TB HDD for internal or external use, correct? Better still, i should be able to buy the new "Seagate 8TB HDD" and use it for archiving (once manually formatted/partitioned to EXT3) ??
In the 2TB Blog post that you referred to af123 specifically addresses this question and says "However, the Linux kernel that is used on the Humax HDR Fox-T2 does not support disks with a GUID Partition Table (GPT) which is required if you want any partitions to be larger than 2TB. (See http://en.wikipedia.org/wiki/GUID_Partition_Table for more details) That gives a practical upper bound to the drive size since almost all of it is allocated to the media partition. It would likely be possible to use a custom kernel on the Humax and add support for GPTs but that could cause other issues and any reversion to standard Humax firmware would be problematic."

Hence what you are suggesting isn't theoretically impossible but is difficult and not without risk.
 

Black Hole

May contain traces of nut
But that's with normal-size sectors/clusters (whatever you want to call them - the minimum allocation unit on a drive used to be one or more sectors, therefore called a cluster, but now drives have larger physical sectors they can be subdivided into logical sectors). The MBR tracks clusters, and can only count up to 2^32, so multiply that by 512-byte clusters and you get your 2TB limit.

Perform a format which uses 4096-byte clusters, and suddenly you can accommodate 16TB without exceeding the cluster count limit and without needing a special kernel with GPT support - assuming the controller can still index all the surfaces, tracks per surface, and clusters per track. As we know, for multi-megabyte video files, the size of the cluster is pretty much irrelevant when it comes to storage efficiency.

I'm not saying it will work, but it is at least plausible.

(Edited to correct the maths)
 
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MartinLiddle

Super Moderator
Staff member
I'm not saying it will work, but it is at least plausible.
But you are assuming that all the other bits of the software and specifically the Humax binary will happily accept 4K sectors and I think there is a great deal of uncertainty about that. The truth is none of us know for certain and it will need someone to actually try it before we really know.
 

Black Hole

May contain traces of nut
Right, I've done a bit of reading and it's all to do with the Logical Block Addressing (LBA) entries in the partition table of the Master Boot Record (MBR). The LBA entries use 32 bits to declare the first sector (let's call it a sector) in each partition, and another 32 bits to declare the number of sectors in the partition. CHS (cylinder, head, sector) addressing only has 24 bits available, and is now totally superseded.

First off, it is possible to define partitions in the LBA to occupy an (almost) 4TB disk with 512-byte sectors. The first three partitions would have to fill the first 2TB, and then the fourth partition would be (almost) 2TB in size (2^32-1 x 512) starting at sector 2^32-1. From Wikipedia:
However, in practice, only certain LBA-48 enabled operating systems, including Linux, FreeBSD and Windows 7 that use 64-bit sector addresses internally actually support this. Due to code space constraints and the nature of the MBR partition table to only support 32 bits, boot sectors, even if enabled to support LBA-48 rather than LBA-28, often use 32-bit calculations, unless they are specifically designed to support the full address range of LBA-48 or are intended to run on 64-bit platforms only. Any boot code or operating system using 32-bit sector addresses internally would cause addresses to wrap around accessing this partition and thereby result in serious data corruption over all partitions.
I believe the Humax OS is based on Linux, so it might be able to support this - but it is irrelevant because (for the HDR-FOX) we would need the main recording partition to fill most of the disk.

With regard to redefining the sector size, so that (for example) 2^32 sectors x 4096 bytes = 16TB, Wikipedia says this:
Versions of Windows more recent than Windows XP support the larger sector sizes as well as Mac OS X, and the Linux kernel has supported larger sector sizes since 2.6.31 or 2.6.32, but issues with boot loaders, partitioning tools and computer BIOS implementations present certain limitations, since they are often hard-wired to reserve only 512 bytes for sector buffers, causing memory to become overwritten for larger sector sizes. This may cause unpredictable behaviour as well, and therefore should be avoided when compatibility and standard conformity is an issue.

In short, it doesn't look like a totally dead duck... yet.

I think it would be useful to split this topic with post 35 starting a new topic "Installing a Drive Larger Than 2TB", with a note edited into the start of the first post that it is a continuation from this topic (with a link back to post 34).
 
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jack616

Member
It is interesting to look at of course but it does seem a lot of hard work for little practical advantage to me.
Is there some reason a very large drive internally is better than having external drives?
Right now I have a 7 port USB hub plugged into one of mine with WD 2TB drives plugged in each port.
I've also tried routing another 4 port hub through that to add an extra 3 ports just to see if it worked (it does)
Initial startup is a bit slow but it does mean a drive crash wont destroy all my work (its not just TV/video use!)
and I sleep a lot better knowing that.

The only downside I can see to my way is an extra mains plug is used and stacking space for the drives
(which can be plugged/unplugged at will of course)

If it was just a case of plug in and go I can see you might want to do that but as it is I'm as confused
about the notion as I am about people trying to "overclock" their cpu when a 6 month wait would just provide
a plug in actual benefit given the rate of processor change.
Or have I missed something?
 
OP
Des in London

Des in London

Member
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...carry on in the spirit of exploration by all means, but do consider first whether it is worth the effort. Even a 500GB HDD only fills up because of bad housekeeping - stuff regarded as valuable to keep would be better archived off to USB drives (in duplicate)

To be honest 'Black Hole' the main reason why i'm doing this is not because of bad housekeeping (and yes you are correct neither myself nor any sane person needs 8TB for the internal storage system!), but because i personally think it's actually worth the effort to do so - to stretch one's mind, and also to push the boundaries of the Humax box to accommodate new technologies; such as increased capacity drives since the original launch of the box way back when; and "Advanced Format" (4K native) Hard Disks that are now commonplace.

I'm only dissuaded by time and not by difficulty - and at the moment time is no barrier to me.

...but it does seem a lot of hard work for little practical advantage to me.
...Or have I missed something?

fao: 'Jack616' - didn't 'JFK' make a speech about landing on the Moon not because it was easy but because it was hard? - so in the spirit of adventure (and to stick two fingers up to the nay-sayers and so-called experts) i won't be stopped just because of perceived difficulties. I mean come on guy's, it's not brain surgery we're doing here but merely programming a brainless device to do whatever we say! (from my laymen perspective of course ;) ).

My only limitation really is specialist computer tech knowledge (does it show? lol), for which i would be grateful for any support from you guys on this forum. I've seen various topics, including one i read recently about someone installing a 4TB HDD - so what's another 4TB's to add to that! (lol).

In order for me to give this a go i need to know if i'm on my own here? Is it ok if i just provide myself, my time and of course my 8TB? - Unfortunately i don't do computer coding so i have absolutely no idea what i'm doing with that regard. Anyone wishing to use me as their personal guinea pig is more than welcome, just let me know how we can do this together :)
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Black Hole

May contain traces of nut
In order for me to give this a go i need to know if i'm on my own here? Is it ok if i just provide myself, my time and of course my 8TB? - Unfortunately i don't do computer coding so i have absolutely no idea what i'm doing with that regard. Anyone wishing to use me as their personal guinea pig is more than welcome, just let me know how we can do this together :)
No coding required - what needs to be done is to (somehow) tell the drive what your desired sector size is, and use an MBR tool to set up the partition table. If, having done that, it doesn't work... it's not going to work.

It doesn't matter what size drive is used for an experiment, it could just as well be a 2TB drive as a 3TB drive - except there won't be the confirmation of success with suddenly having 3TB available. The real problem is reading up on the specific drive and finding out how to change the emulated sector size (the method could be different for different drives, particularly from different manufacturers).

However, even if nothing else falls over, I anticipate the Humax may not get its free space calculations correct for the Media pie chart, and may decide it can't record any more because the disk is full when it isn't. If you change the sector size to 2K and the Humax code thinks it's 512 bytes, there will still only be 512 bytes of data stored in each 2K sector and nothing has been gained.

I think it's fair to say we're all keen for you to give it a go and see what happens, but warn that it's a rocky path with no certainty of success - and with so little potential practical benefit (other than the thrill of the chase) that thus far none of us has been inclined to pursue it.
 

af123

Administrator
Staff member
The custom firmware kernel does have support for large sector disks and GPT/EFI partition tables enabled but the stock firmware doesn't. It has never been tested though. The kernel version, 2.6.18, is early in the 2.6 train and there were multiple fixes in this area in later versions, YMMV!
 

Black Hole

May contain traces of nut
So maybe a 3TB drive could be built with GPT and it would "just work" using CF?

The problem as I see it is not so much the OS as the Humax software that runs on top - they may have hard-coded the sector size.
 
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