Need a hard drive interface comparison chart (+ other questi

[guiri]

Guys, do you know where I can find a simple and to the point hard drive interface comparison chart?

Ie, which interface is called what and how fast it is compared to the other and so on.

I'm getting ready to buy the Infrant ReadyNas NV+ and just wanted to do a little research before I buy the drives.
Sata is faster than ata and parallel ata?
What is Sata-300?

I was initially going to stick 4x750gb drives in a raid 1 configuration for around 2tb of storage but I'm having second thoughts.

The 750's will run me around 280-300 each but if I do 500's, I can get away with 150 each. That's about 600 in savings for 500gb..
Not sure if I need it or should get it?

I'm thinking that soon the 750's are going to go down as I think they'll release 1tb drives soon but then, if I get the 500's and then upgrade, what the hell do I do with the 500's?
Any thoughts on this?

Thanks

George

 

[sithscout80]

PATA/ATA/IDE - 100MB/s - 133MB/s
SATA - 150MB/s or 300MB/s
SCSI - 160MB/s or 320MB/s

Interface speeds do not matter because they only indicate the theoretical maximum for data transfer rates. Hard drives cannot provide data at this speed, so maximum data transfer speed is irrelevant.

If using the Infrant ReadyNas NV+, transfer speed is even less important as it is using a gigabit ethernet, which would only support speeds up to 125MB/s, again theoretical maximum for the network speed.

If you are using the Infrant ReadyNas NV+, you must use Serial ATA disks, so SCSI and PATA/ATA/IDE will not work. You can either use SATA or SATA II disks. They are backwards compatible.

If you don't need 1.5TB of space (4x750GB in RAID 1), then go for the 500GB drives. The savings in money is significant.

If you want a breakdown on the best $/GB hard drives, look at the link in my signature.

 

[guiri]

I was going to go with Sata anyway.

What is Sata 300 and Ata 150

How come I was told that with 750's I'd get around 2TB? I couldn't figure that one out because I got the impression that the FOURTH drive is providing the redundancy but that didn't make sense to me.

So, you need a minimum of FOUR drives for redundancy, right?

Is their Xraid version level 1 or 5 and also, is there a quick breakdown on the raid levels and what they use in HDs and what they do?

Finally (for now anyway would I be better off going with slower and cheaper drives as I might even run this through my wireless router which'll slow it down even more..?

Thanks

George

 

[sithscout80]

The ReadyNAS NV+ supports RAID 0, 1, and 5.
RAID 0 has no redundancy, so if one drive fails, you lose all your data, but you can use the whole space (4 x 750GB = 3TB).
RAID 1 has redundancy. The amount of space you can use is ((4 x 750GB)/2 = 1.5TB).
RAID 5 has redundancy at less of a cost than RAID 1, so the amount of space you can use is ((4-1) x 750GB = 2.25TB).

Minimum Number of Drives:
RAID 0: 2 Drives
RAID 1: 2 Drives
RAID 5: 3 Drives

Information on RAID

The difference between SATA 150 and SATA 300 is in their data transfer speeds. Some SATA 300 devices include some other features.
Dispelling the Confusion: SATA II does not mean 3Gb/s

The XRAID feature is their proprietary software/hardware that allows you to add hard drives to the array and the space will automatically start being used. No configuring is required to add or remove drives from the array.

All hard drives run about the same speed (at 7200 RPM). I suggest just getting the best $/GB for the hard drive since data transfer speed will not be an issue.


For what purpose are you using these drives and that amount of space?

 

[guiri]

I guess he was talking about raid 5 then.

I just assumed since raid 5 can use 3 instead of two I automatically assumed it was the other way around.

What I don't understand is is, how does raid 5 work.
If you have 4 drives but you can use THREE of them at the full amount of space and you only "lose" one so to speak. How the hell does it make the info redundant?

I mean, it's not like some kind of parity check like when you download a file or something? Don't you have to have the same amount of space for the drives that are going to be used for the redundancy? (Did I spell that correctly?)

That's what I wanted anyway. Raid 5 with their Xraid version and stick either 4x750 or 4x500 where at 750 I'd get a little over 2TB and with 500's I'd get around 1.5TB and it would be completely redundant?

Is this correct?

As for what I want to do? Just storage of files and access to them. I also want to be able to access it from the outside through a browser.

Sometimes I'm outside and want to access a file and this way I could log on through a browser and pull that file up (correct?).

Am I on the right track here (before I order the stuff

George

 

[sithscout80]

RAID 5 provides redundancy by use of a parity bit. (For simplicity of the explanation, assume all the parity bits are on 1 hard drive of the 4 (This is actually what RAID 3 does. RAID 5 just splits up the parity bits across all the drives, so all the drives contain some data and some parity bits).

Parity bits are calculated by the XOR function. Here is the truth-table for the XOR.

A B | out
------------
0 0 | 0
0 1 | 1
1 0 | 1
1 1 | 0

If you know 2 of the 3 bits, you can calculate the third. For the example above, let's say that the data that corresponds to input B is not available (the drive failed), we can recreate the data, with the XOR function again.

A out | B (calculated by doing A XOR out)
------------
0 0 | 0
0 1 | 1
1 1 | 0
1 0 | 1

As you can see, B was calculated to be the same values as it was initially. This can be expanded to any number of inputs because XOR is effectively calculating if there is an even (equal to 0) or an odd (equal to 1) number of "1s" in the input.

Take this string for example. There was a bit by bit XOR done on it and we know that the XOR output equalled 1 (odd number of "1s"). Sometime since storing our data, a bit became corrupted (represented by the X). Using the knowledge of the XOR function, what is X supposed to be?


10010101100X = 1

X should be a 0 because that would make an odd number of "1s" in the string, so that matches the parity bit (XOR output).

Just so you can see that parity and XOR work on 3 inputs, here is the truth-table.

A B C | out
------------
0 0 0 | 0
0 0 1 | 1
0 1 0 | 1
0 1 1 | 0
1 0 0 | 1
1 0 1 | 0
1 1 0 | 0
1 1 1 | 1

You can read more about the different RAID levels in the article I linked to in my previous post.


You can access the ReadyNAS NV+ over the internet if you want. Be warned though you'll most likely be limited by your internet upload speed where you have the hard drives. Do you know what hard drives you'll be buying to put in the ReadyNAS NV+?

 

[guiri]

I know access won't be superfast through the net and that's fine. I won't use it to download music or stream anything. It's mostly for stuff like..I'll be talking to someone and we start talking about dogs and I'll go, here, want to see pics of my dogs..you get the idea.

I just want to be ABLE to do it

Don't care what drives I'll use really. Was going to use the Seagate 750's but now I'm having second thoughts.

They'll run me $1200 and I just found some 500gb's on newegg for 100 a piece which will save me $800 bucks. That's good money and I still get 1.5TB which IS a lot of space and probably more than I'll need for awhile, ESPECIALLY since now this stuff is redundant.

See, before I just to keep several copies of the same thing (I have 3x300gb drives at home) and I keep switching to update stuff. Here I won't have to. Mind you, you can still always lose info but chances are pretty small I guess.

Here's the link to the 500gb on newegg.
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136107

Can't find the warranty on it though so I may have to call about that one.
It's recertified though. Not sure if I should stay away from that or not. I've never bought a refurb drive before.

George

 

[sithscout80]

I wouldn't go for recertified. They have shorter (90 day) warranties. They are called recertified because they were returned to the manufacturer and the manufacturer repaired them and are selling them again.

I would spend $15 more per drive and get this:
Western Digital 500GB SATA 3.0Gb/s

If you want to ensure your data is secure, I would buy an extra hard drive, so in the case that one hard drive fails, you can remove it and immediately replace it with the spare. You can then take your time with the warranty and replacement of your failed drive. When a drive fails, there will be a performance decrease. If a second hard drive fails before you get a replacement, all your data is lost, because it cannot handle 2 drive failures.

If I was using a RAID array, I would keep a spare hard drive in case a hard drive in the array failed.

 

[guiri]

Thanks for the (more) good advice

Didn't think about the spare drive which really is going to change things because now it's not 4x$300, it's 5x$300 for the 750's vs 5x$150 for the 500's.

I'll probably be buying them at Best Buy for Business because I can get 18 months no interest there and I WILL get some discount on their prices.
Not much but still, the no interest option is worth something to me.

I actually HAVE the money to pay for it cash but I need to hold onto that cash so I'll have to do it this way.

Their price is $161 but like I said, I should be able to get it down a little. I'm also getting the NAS from them.

After all, 1.5TB is a pretty good amount of space.

Anything else I have to think of?

Thanks for all the help so far.

George

 

[sithscout80]

That's all I can think of right now.

 

[guiri]

Then, I really appreciate your help and I'll keep you posted on how it went

Thanks

George

 

[guiri]

Brother sith, I've got a problem.

I placed the order for the NAS and five drives and guess what? I just remembered that they have a hard drive compatibility list and the drive I just ordered is NOT on that list.

Look at the bottom on this page http://www.infrant.com/wiki/index.php/Hardware_Compatibility_List_-_Hard_Disks

Any suggestions from the available drives?

Thanks

George

 

[sithscout80]

From the list of drives, the Samsung one is the next best price for 500GB.
http://www.newegg.com/Product/Product.asp?Item=N82E16822152052

You could also just try it with the Western Digital drives and see if it works. Compatibility lists are not usually extensive for the reason of not wanting to try every possible combination.

Your drive does fall in the category that says

"Western Digital JS/KS/YD/YS - These models of Western Digital disks may return inaccurate temperature causing intermittent warnings and possible forced shutdowns, and we cannot recommend these disks at this time."

These problems may or may not occur, that is unknown. One thing to look at before you cancel your orders is if there is a way to disable the temperature sensor. If you disable the sensor and you ensure you have enough airflow to keep them cool, it should be fine.

Also check to see if you can return the drives to Best Buy if they don't work, for no extra cost. If you can, you might as well try them out.

 

[guiri]

First I'm too damn stupid to disable the sensors. Second, I would have no idea if there's enough airflow, AND, I would like this unit to be quiet.

As for the Samsung, what's the warranty on these things? How are they on warranty returns and are they good?

You're probably right about the drives that they might work but my life is a virtual Murhpys law thing.

If it can, it WILL break. I'm scared bro..

I'm sure I can return them but that would suck. For me and for them. After all, FIVE drives..?

The list of drives is very short and I know they're just trying to cover their ass but...

George

 

[croc]

The nv+ is a nice platform. Congrats. Unless you're a huge music / movie buff, 1.25 TB is a LOT of space. I'd save the $600...

 

[guiri]

I may not be able to save that money after all

George

 

[guiri]

Also, if I disable the sensors I betcha anything I'll void the warranty?

Are they on the outside or inside?

George

 

[sithscout80]

Samsung is a good hard drive company. Their drives are on the compatibility list and should work well. It is just $15 more than the Western Digital ones. You should get the Samsung if you are worried about it.

Samsung's warranty is just the same as other companies warranty.

To disable the temperature sensors is easy, it is part of the software that comes with the unit (it doesn't void the warranty). It is described here on page 58.
http://www.infrant.com/download/UserGuide_V3.pdf

The unit should be getting enough airflow that temperature doesn't need to be worried about. There is a built in fan that will allow proper airflow, just don't put it in a closed off corner where air can't get into it at all.

 

[guiri]

..problem is, the drive's not on their site but then, the NV+ wasn't either so I'll e mail him and ask him to dig this drive up instead.

I can buy it from newegg for 130 bucks but then i have to fork up the cash

I probably save on tax too. Damn, there's always something isn't there.

Well, Samsung it is. The seagates are another 30 bucks or so.

Are they worth it?

Thanks again

George