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Adding 4TB - total storage volume not increased

jh75
Aspirant

Adding 4TB - total storage volume not increased

Hi,

We have a Readynas nv+ v2 used for backing up to. It has 4x2TB hdd’s.  The NAS has run out of space and I am in process of adding 2 new 4TB drives.

I am adding one drive at the time and have only added 1 drives so far. After adding 1x 4TB drive the storage ‘size’ has not increased – it seems that only 2TB of the new drive is used.

I can see in the admin section (under info) that the 4TB (3726GB)  is recognised.

 

Before adding the second 4TB drive I want to make sure this work.

Any idea how expand the storage over all drives?

 

Thanks

JH

Model: ReadyNASRND4210v2|ReadyNAS NV+ v2
Message 1 of 13

Accepted Solutions
StephenB
Guru

Re: Adding 4TB - total storage volume not increased


@jh75 wrote:

 

I am adding one drive at the time and have only added 1 drives so far. After adding 1x 4TB drive the storage ‘size’ has not increased – it seems that only 2TB of the new drive is used.

 


This is normal.  The system can't use the full drive space without sacrificing RAID redundancy.

 

When you add the second disk there will be a second resync and the volume will expand by 2 TB.  You likely will be prompted to reboot the NAS half-way through that resync

View solution in original post

Message 2 of 13

All Replies
StephenB
Guru

Re: Adding 4TB - total storage volume not increased


@jh75 wrote:

 

I am adding one drive at the time and have only added 1 drives so far. After adding 1x 4TB drive the storage ‘size’ has not increased – it seems that only 2TB of the new drive is used.

 


This is normal.  The system can't use the full drive space without sacrificing RAID redundancy.

 

When you add the second disk there will be a second resync and the volume will expand by 2 TB.  You likely will be prompted to reboot the NAS half-way through that resync

Message 2 of 13
JBDragon1
Virtuoso

Re: Adding 4TB - total storage volume not increased

You can see this looking at the HDD storage space Calculator.

http://rdconfigurator.netgear.com/raid/index.html

 

Just drag a drop the HDD's and you can see how much space you get on the right.  Play around with things.

So you start out with 5.43 TB of Space with 1.82 TB used for protection.  That's how much storage space a 2TB HDD works out to.  When you add a single 4TB HDD, you are basically wasting 1.82 TB of space.  Think about it as Data is spread out though the 4 HDD's.  With one twice as large. there's no other HDD what enough space, equal amount of space where if one dies, the other one can cover it.

 

Once you add a second 4TB HDD, you now get 7.25TB of space, and 3.64TB used for protection.  3.64 is the amount of storage space on a 4TB HDD.    I know, you're thinking you should get like 4TB of space right?  But your total gain is only about 2TB.  Once you get to the 4th, you end up with 10.9TB.

 

I happen to have 13.62TB of space from 6 3TB HDD's.  At some point I plan to switch them out to 6TB HDD's.  That would boost me up to 27.2TB of space.  Or doubling what I currantly have.  Losing storage space for Redundancy is worth it.   It's still no BACKUP!!!  You're NAS could break down, or it gets stolen or you have a fire, etc.  Things happens.  If 2 HDD's take a dump on you at the same time and it can happen as rebulding the new HDD really works the other HDD's hard.  In general the HDD's may be around the same age, and a second HDD takes a dump in the middle of a rebuild and there goes your data!!!!  it takes HOURS to rebuild a new HDD.  Larger it is, the longer it's going to take.  Don't count on a NAS to save your Data!!!  

Message 3 of 13
StephenB
Guru

Re: Adding 4TB - total storage volume not increased


@JBDragon1 wrote:

You can see this looking at the HDD storage space Calculator.

http://rdconfigurator.netgear.com/raid/index.html

 

 


Alternatively, for the default XRAID you can sum the disks and subtract the largest.  That will give you the results in TB (see below).


@JBDragon1 wrote:

 3.64 is the amount of storage space on a 4TB HDD.


To explain this a bit more fully - there are two units of measure here.  The disk drive is 4 TB. 1 TB = 1000*1000*1000*1000 bytes.  3.64 is what the NAS volume will show, because it is using TiB, not TB.  1 TiB = 1024*1024*1024*1024 bytes - about 10% bigger than 1 TB.  Unfortunately the NAS (like Windows) labels the size as TB or GB - even though it is really TiB or GiB. 


@JBDragon1 wrote:

 Losing storage space for Redundancy is worth it.   It's still no BACKUP!!! ... Don't count on a NAS to save your Data!!!  


Totally agree here.  RAID is simply not enough to keep your data safe - for all the reasons you mention.  Unfortunately a lot of people discover this the hard way.

 

Message 4 of 13
JBDragon1
Virtuoso

Re: Adding 4TB - total storage volume not increased

Should we blame Microsoft or the HDD makers for Advertising sizes, or showing sizes that that really confuse everyone.   Isn't it the whole RAM thing being 1024, while HDD are 1000, and Windows just treats them both the same at 1024?  So while RAM shows correctly, HDD space shows less, because all them 24 bytes extra add up.   I'm not sure why they didn't just both just be the same?  Either Ram or Storage, but it's been confusing people for a very long time.

 

Message 5 of 13
StephenB
Guru

Re: Adding 4TB - total storage volume not increased


@JBDragon1 wrote:

Should we blame Microsoft or the HDD makers for Advertising sizes ...  Either Ram or Storage, but it's been confusing people for a very long time.

 


It's been this way so long, I'm not sure who started it.  I recall (many years ago) that 1024 multiples were used in early PCs to avoid the divide (using a right shift instead).  Though that is anecdotal, and might well be wrong.  Though of course 1024 is the logical unit for RAM.

 

 

Message 6 of 13
Sandshark
Sensei

Re: Adding 4TB - total storage volume not increased


@StephenB wrote:

 

 

It's been this way so long, I'm not sure who started it.  I recall (many years ago) that 1024 multiples were used in early PCs to avoid the divide (using a right shift instead).  Though that is anecdotal, and might well be wrong.  Though of course 1024 is the logical unit for RAM.

  


RAM uses multiples of 1024 because there are physical address lines, so the total number of locations must be a power of two (a round number in binary) since each line has two possible states (0 and 1).  So it only made sense that a Kilo, Mega, Giga, etc. would be a multiple of 1024 (an even power of 2) instead of 1000.  This was established before hard drives even existed by general usage, not by actual standard.  The shift instead of divide by two has similar roots (two states for each location vs, two states for each address line), but they are not hard linked.  

 

Hard drives have no similar physical restriction.  I remember 17 sectors per track being common as 5.25" hard drives became mainstream, but that varied some between manufacturers.  In the very early years, some manufacturers used multiples of 1024 for drives as well, but their drives "looked smaller" than the competition that used multiples of 1000, so multiples of 1000 became the norm (as well as folllowing the IEC standard, where multiples of 1024 did not).  Rounding drive size up instead of using fractional sizes also became the norm.  These and the "raw vs, formatted" capacity all add to the confusion of just how much a drive will hold.  The bottom line is the drive manufaturers all want their drives to advertise as being as large as they can get away with.

 

In 1999, the IEC decided enough was enough and invented (or at least standardized) the KiB, GiB, TiB, etc. for binary multiples.  Computers were now mainstream, and the old "industry standards" were confusing to the general populous, especially since that extra 24 doesn't actually "add up", it multiplies.  The difference was really staring to show with TB=1000x1000x1000x1000 vs. TiB=1024x1024x1024x1024.  But except to explain the difference between the size of drives and RAM, the "KiB", "GiB", "TiB", etc. have yet to become commonly used in the electronics industry.  1024 bytes of RAM is still a "K" not a "Ki" pretty much everywhere I look.  Microsoft is just following the crowd (or stagnating with it, I suppose), and the confusion persists.  Blame old guys (and gals) like me and Bill Gates (though he's out of the game now) for this.

 

Here is a good reference: Prefixes for binary multiples

Message 7 of 13
jh75
Aspirant

Re: Adding 4TB - total storage volume not increased

Thanks,

 When adding the next 4TB drive it expanded across as expected.

 

j

Message 8 of 13
StephenB
Guru

Re: Adding 4TB - total storage volume not increased


@Sandshark wrote:

Computers were now mainstream, and the old "industry standards" were confusing to the general populous, especially since that extra 24 doesn't actually "add up", it multiplies.  The difference was really staring to show with TB=1000x1000x1000x1000 vs. TiB=1024x1024x1024x1024.  But except to explain the difference between the size of drives and RAM, the "KiB", "GiB", "TiB", etc. have yet to become commonly used in the electronics industry.  1024 bytes of RAM is still a "K" not a "Ki" pretty much everywhere I look.  Microsoft is just following the crowd (or stagnating with it, I suppose), and the confusion persists.  Blame old guys (and gals) like me and Bill Gates (though he's out of the game now) for this.

 


I believe OSX uses 1000 multiples, so confusion continues to abound.

 

My recollection on the shift went back to the CP/M operating system, which of course was back when dinosaur computers roamed the earth.  https://en.wikipedia.org/wiki/CP/M

Message 9 of 13
JBDragon1
Virtuoso

Re: Adding 4TB - total storage volume not increased

I still kind of remember CP/M.  I remember screwing with it on my Commodore 128 back in the day.   On of a number of Commodore computers I've owned starting with the Vic-20 with a Cassette Tape Drive.  Them were the days.  Take 20 minutes t load up a program only to have it crash near the end have have to rewind the tape and try again.    My first 5-1/4" floppy with my C-64, after using the tape drive with that for a while.  My 128 with the 5-1/4" and 3.5" Floppy drives, which I ended up running a BBS on.  My 128D, My Amiga 500 and finally getting my first HDD which was a SCSI drive, 5-1/4" Full Height 40 Meg drive.  That was pile of money, ended up running my BBS on that.  Got a Amiga 1200,  Finally went to Windows 95 on a Gateway 2000 computer. My first 3DFX graphic card.  These days I'm on a Windows 10 Desktop which I built.    It's really pretty Amazing I have a computer the size of my iPhone that's 1000 times more powerful and the 128 Gig's of storage.  Tech has moved so fast in such a short period of time.  I couldn't dream back then what we would have now.   My NAS serving me up hundreds of HD movies anywhere I'm at. with TB's of storage.  You just have to think WOW.

 

My Mac experiance was on my Amiga 500 running  a Mac Emulator so that I could run Netscape.  Some things never change.  Now you have Mac's that can also run Windows.   Not so much Emulation, but still,.....

 

 

Message 10 of 13
StephenB
Guru

Re: Adding 4TB - total storage volume not increased


@JBDragon1 wrote:

Them were the days.  Take 20 minutes t load up a program only to have it crash near the end have have to rewind the tape and try again. 

 


Paper tape was even more fun, especially if you stepped on it while rewinding...

 


@JBDragon1 wrote:
My NAS serving me up hundreds of HD movies anywhere I'm at. with TB's of storage.  You just have to think WOW.

 


Very true.

Message 11 of 13
JBDragon1
Virtuoso

Re: Adding 4TB - total storage volume not increased

No Paper Tape or Punch Cards for me!  Paper Tape is just a continues puch card.  That's a little before my time.  50's, 60's.  Even earlier for things like to program looms.  But as far as personal mainstream home computers goes, it was Cartrages, and Tape Drive.  Which my Vic-20 used both.  Back then I played with a number of computers, many I don't remember anymore.  They didn't last long in the marketplace.

Message 12 of 13
StephenB
Guru

Re: Adding 4TB - total storage volume not increased


@JBDragon1 wrote:

 ... That's a little before my time.  50's, 60's.  


No, they lasted longer than that - just never reached home computers.

 

Regretfully paper tapes persisted for me up into the 80s.  Towards the end they became mylar instead of paper, and you could get a really bad cut if you mishandled the power-rewinder.  These were used in a diskless minicomputer that was part of a medical patient monitoring system (no flash boot back then).

 

My life with punch cards ended in the mid-70s (when I stopped using IBM 370 mainframes).

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