Warning purchasing USB hard drives


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At least one user learned that drives harvested from USB enclosures may include a small HPA, reducing its capacity by a minuscule amount. Although not a big deal, it can be a problem if you assign it as parity. Adding drives without the HPA will be a tiny bit bigger and would be a nuisance going forward. Removing an HPA is easy to do, and you want to do it before preclearing it!

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An HPA is a "Host Protected Area" -- an area reserved on a hard disk for a variety of purposes.

 

It's most commonly known in UnRAID as a Gigabyte-related issue, as Gigabyte motherboards used to save copies of the BIOS in an HPA they would create on an attached drive.    It's also been used by Dell to store Media Direct files;  by Lenovo/IBM to store recovery data; and by others for various purposes.  The issue that prompted this thread was WD using an HPA to store some info unique to its MyBook drives.

 

When you create an HPA, you effectively reduce the size of the hard drive by the size of the HPA.  The issue that creates here is that any drive with an HPA will be slightly smaller than the same size drive without an HPA.  Since parity must always be >= the largest data drive, a drive with an HPA can't be the parity drive if there are other drives of the same capacity in the system that don't have HPAs.

 

It's not a problem for a data drive -- you lose a few KB, but that's the only issue.    But clearly you should be aware of this if you're harvesting drives from external enclosures.

 

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HPA is not uncommon for many purposes. In fact, you may wish to use HPA yourself :)

 

The key is knowing about it. HPA "detection" is very simple;

root@unraid5:~# hdparm -N /dev/sda

 

/dev/sda:

max sectors  = 7814037168/7814037168, HPA is disabled

 

Now, why would you want to use it?

#1 reason I have recently used it, increase the spare area on SSDs. Older SSDs had very small spare area.

#2 short stroke a 4TB drive into a 2 or 3 TB array (or 2TB into 1TB array), aka rightsizing/downsizing. This is a temporary step in the process of upgrading an array when called about a failure and avoids buying a drive only to be used for days.

Thus if you find you have a HPA on parity, you can quickly put one on new drive and move ahead.

 

 

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thanks for the heads up. Have Toshiba 5TB arriving soon and it likely has hidden crap. :P

 

Maybe. But you will be the first person using a 5T drive. Depending on the size it may need a myMain config change even if the is no HPA. Let me know when you get it and I can direct you.

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thanks for the heads up. Have Toshiba 5TB arriving soon and it likely has hidden crap. :P

 

Maybe. But you will be the first person using a 5T drive. Depending on the size it may need a myMain config change even if the is no HPA. Let me know when you get it and I can direct you.

 

It will be placed as parity drive on a full 26 TB server (all 2 TB drives). Then I can start replacing those drives with larger and adding the 2 TBs to Tower2

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It will be placed as parity drive on a full 26 TB server (all 2 TB drives). Then I can start replacing those drives with larger and adding the 2 TBs to Tower2

 

I presume you've already upgraded to v5 (or 6) ... but a more compelling question (given that you've currently got all 2TB drives) is whether or not you've confirmed that the system supports > 2TB drives ...

 

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It will be placed as parity drive on a full 26 TB server (all 2 TB drives). Then I can start replacing those drives with larger and adding the 2 TBs to Tower2

 

I presume you've already upgraded to v5 (or 6) ... but a more compelling question (given that you've currently got all 2TB drives) is whether or not you've confirmed that the system supports > 2TB drives ...

 

Both boxes are running v5.x. I can't find a definitive yes (or no) on either motherboard as to any limits on HDD size.

 

Asus M4a785-M (older tower)

Biostar A880GZ (new box)

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Based on the response from Asus to a question r.e. supporting drives > 2TB on that motherboard, it appears the motherboard ports don't have any problem with that.  The other question is whether or not any add-in controller you might be using supports them.  For example, the Adaptec 1430SA often used in UnRAID systems a couple years ago DOES have the ability to support the larger drives, but only if you flash it with updated firmware.

 

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Based on the response from Asus to a question r.e. supporting drives > 2TB on that motherboard, it appears the motherboard ports don't have any problem with that.  The other question is whether or not any add-in controller you might be using supports them.  For example, the Adaptec 1430SA often used in UnRAID systems a couple years ago DOES have the ability to support the larger drives, but only if you flash it with updated firmware.

 

I did the early testing of motherboards and controllers to test for 3T drive compatibility.

 

SEE HERE

 

What I found was even relatively old controllers worked properly, including the 1430SA. I am curious about this BIOS update you mention because I did no such update.

 

The sole exception to compatibility was the BR10i which uses an LSI 1068 chipset. Seems they intentionally build obsolescence in and made it incompatible, and would not release an update.

 

After this study I did buy an Areca ARC-1200 and had to flash it to get 3T support.

 

I would be very surprised to find a motherboard new enough to be considered for unRaid that would not support them. Have there been examples?

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5TB arrived a day early. Removing the case is definably a one-way proposition (no screws, uses locking tabs). Not going to be able to send it back now. :P I believe these are re-branded Hitachi drives. model: MD04ACA500, Mfg data 2/27/14, firmware A0.

 

Preclear on a 2TB takes about 22 hrs so this one will be couple days

 

PS. instructions on ruining the case

http://goughlui.com/?p=4688

 

PSS. No hidden partitions (at least Windows 7 can't see any). Just warranty PDF and autorun to install backup software.

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What I found was even relatively old controllers worked properly, including the 1430SA. I am curious about this BIOS update you mention because I did no such update.

 

Obviously it depends on when you purchased your 1430SA's ... or, more precisely, when they were made and what firmware revision was on them when you got them.    The updated BIOS was released on 8 Nov 2010 (Release 2507).  The Release Notes for this update include the following:

 

4. Major Functional Changes:

--------------------------------

1. Added support for drives larger then 2TB in size.

 

 

Your testing thread is dated March of 2011 ... I suspect you purchased/borrowed a 1430SA that was fairly new at the time ... so it already had the Nov 2010 update.  But a lot of folks using UnRAID are likely to have controllers earlier than that -- and they need to apply the update if they want to use this controller with v5/v6 and drives > 2TB.

 

 

 

I would be very surprised to find a motherboard new enough to be considered for unRaid that would not support them. Have there been examples?

 

I've seen a LOT of motherboards that won't support drives > 2TB.    No new boards are going to have this issue -- so it depends on what you consider "... new enough to be considered for unRAID ..."      I agree it's very unlikely anyone building a system today would be likely to have this problem ... but if you're planning to use a board from an older system, it's a good idea to check compatibility with the larger drives.    With a bunch of older systems being sidelined by those who don't want to use XP anymore due to end of support, there may be some who want to repurpose that hardware for basic UnRAID systems ... and some of these could easily have motherboards that don't support the larger drives.

 

 

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5TB arrived a day early. Removing the case is definably a one-way proposition (no screws, uses locking tabs). Not going to be able to send it back now. :P I believe these are re-branded Hitachi drives. model: MD04ACA500, Mfg data 2/27/14, firmware A0.

 

Preclear on a 2TB takes about 22 hrs so this one will be couple days

 

PS. instructions on ruining the case

http://goughlui.com/?p=4688

 

PSS. No hidden partitions (at least Windows 7 can't see any). Just warranty PDF and autorun to install backup software.

 

I am confused by your screenshot. It says 500G?

 

Run this command in the Linux command line:

 

hdparm -N /dev/sdX

 

where sdX is the device name for the 5T drive.

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If you run myMain you can monitor the running preclear. Have you tried?

 

tried it just now :)

 

Pre-Read. 27% @ 181 MB/s (2:04:02)

 

I use a KVM with a 21" monitor for the two servers so I have it up on the screen now too.

 

Wow! 181mb/sec. It is cooking!

 

Do me a favor ...

 

Just above the drive table in myMain, to the right side, there is a prompt that says "Select View". Click on the view called "Detail." Find the 5T drive in the list, and look at the value in the "Size (k)" column. Tell me what number you see there.

 

Does myMain report a possible HPA?

 

 

 

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The HPA warning would show up with the drive icon in the far left hand column.

 

MyMain accepts any size as not having an HPA if it ends with 3 specific digits (must be 552 if you aren't seeing an HPA warning). Every drive size from ~300G - 2T had this special size. I thought the drive manufacturers must have made a pact to always pick that type of size, but with 3T and 4T the sizes did not end that way so showed up as possibly having an HPA, and myMain needed a config change to not flag them. If you are not seeing the warning, the 5T drive is back to using the size ending with the 3 specific digits which must be 552.

 

I'll need to confirm the size of the 6T drives to see if they need a config change or also end with 552.

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