Can you have 5 drives in RAID1?

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newbie12

newbie12

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According to this, the answer is a sounding *yes*, but others are arguing that it is NOT possible, and only works on even number of drives and not odd numbers. Well, it should be possible, right? Because all drives get the same data copied over to(so effectively you would have 5 backup drives, except that they're all in one place rather than in their seperate boxes), so why doesn't odd number of drives work with RAID1? Please explain...

I was looking into getting an external hardware RAID enclosure for 5 or 4 drives, and have them all do RAID1, so effectively have a contingency plan if any one, two, three or four(if getting a 5 bay one)drives go dead at the sametime....

What do the experts here say about this?
 
Solution
USAFRet


A single RAID 1 array can contain 2 or more physical drives.
As the far right thing in...
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You could.

Although you waste 4 hard drives worth of space for that redundancy.

A much better idea would be a raid 5 or raid 6 which allows for 1 drive or 2 drive failures, respectively.

I use Crashplan to backup all of my files, 8+ terabytes, for about $8 a month.

Along with a local backup to a custom built nas4free server.
 
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Yes but why? You can add as many drives to the array as the controller will allow. At some point, so many drives in RAID 1 becomes inefficient though - having that many identical drives in one place gives you a single point of failure. Why not RAID 5, 10, or even 6? You get more space and performance that way. I've been using RAID for years. What I do now is - RAID 1 in my PC, RAID 5 on my NAS, and a cloud solution. You could even add a portable HDD and store it offsite somewhere. Spread things out a bit.
 
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Is that a 100% yes, or a *yes* but [insert catch here]?

Well what if all four HDDs suddenly die at the same time? I've read stories of two dying at the same time, three and four are not too far-fetched, you know! :langue:

I heard those RAID levels induces URE - Unrecoverable Read Errors....which sounds scary.... :/

As much as I would like an online backup cloud solution as well, I can't and won't because 100KB/s speed will take far too long and will inconvenience me too much...and that's the fastest upload speed when no one is using the the net...would usually hove around 72KB/s or less when there is someone using the net...

I do have a local backup, two actually, except I think one just died a few days ago(the device won't boot up - so either the drive is dead or the board that's connecting to the drive is dead or both!) and the other one looks like it's on its way to dying soon(kept disconnecting itself every now and then - but I suspect that could be due to the temperature it was on, like 60 degrees Celsius in its enclosure, so I took it out and it hovers around 40 degrees Celsius bare without the plastic enclosure....what was Seagate thinking on not adding breathing holes to their expansion drives??! Might have to drill in some holes or and add in a 80mm fan or something to it to cool it off whilst it's in the enclosure, as I heard temperate kills HDDs...), which is why I was looking up for another external backup solution, found that hardware RAID enclosures exist and chased that for a bit and here I am...

Yeah well that's if the RAID controller or box decides to go out....in which case I would need a replacement board or the entire box even!

RAID 5 and 6, was explained above, apparently induces UREs(or so I've read....) and as for RAID 10, well... I don't know....just wanted to have the most redundancy as I can, so that's how I came to RAID 1....for RAID 10, if two drives die, then there goes the array....if two drives die in RAID 1, the array is still operational, because you have three drives still alive and kicking...



Hmm, never thought of encrypting tiny stuff like this and then emailing myself with them.....could be a good idea...but what if my email account gets hacked into? Oh wait, then I would then password it but then have the password NOT be in the email but written down somewhere else.....preferably on paper, since you can't hack paper....as it's not an electronic state.... 😛 AH, might as well have these as hardcopies....
 
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What is this? You come here for help, asking "What do the experts here say about this?" And then debate every solution - with a complete quote by quote breakdown on why you think your giant RAID1 is somehow a good idea? BTW, you can lose up to two drives in RAID10 not to mention it improves your performance and doubles your capacity against a four-disk array of the same size drives. Don't over complicate it, this is a simple backup solution for a single user. RAID doesn't even need to be an option.
 
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Oh I did too! :chaudar: heh..... ... .. .

Sorry about that if that's how it came across that way to you, wasn't intentional... :ouimaitre: I blame my mindset from something else, whilst waiting for replies....

Okay, lets start over, so it's a YES for I can do 5 drives in RAID1 config and doesn't necessarily need to be an even number of drives for it to work, but ideally it would be more effective to use another RAID config, such as 5, 6 or 10 instead?
 
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Raid 10 isn't just 2 drives.

Raid 10 is half of the available space.

Although if you had 4 drives ... 2 drives would still be the answer.

Raid 10 does require an even number of drives.

Every drive has a mirror of itself and you have multiplier pairs of mirrors in a raid 0 configuration.

This may be where you heard the "even" term.
 
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I don't mind him playing devil's advocate.
That's how you can be sure your choice is correct.


There is no catch for a raid 1 with 5 drives or even 10 drives.
It depends on what the raid controller will support.

Crashplan only has about a 500 kilobyte / second upload speed.
As you can imagine 8 terabytes took about a month to upload.
But now my data is safe and sound.
 
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Unrecoverable read errors are for any hard drive or ssd.

https://www.google.com/search?q=unrecoveryable+read+error&ie=utf-8&oe=utf-8

It doesn't matter if you have a raid 1, 5, 6, 10 or even 0

What a raid 1 does it when it detects data that can't be recovered from a hard drive it pulls the good copy from it's mirror and then tells you "PROBLEM ON DRIVE 1 REPLACE DRIVE 1 NOW"

A raid 10 does the same thing just with multiple raid 1s striped together.

Raid 5 and 6 reconstruct your data based on the parity calculated from the data.

For instance for raid 5,

5 + 8 = 13

If drive 1 held the number 5, drive 2 held the number 8, and the hypothetical drive 3 held the number 13 you can reconstruct any of the other numbers if any 1 drive fails.

Raid 6 works in a similar much more complicated way but the result is 2 drives can fail before your raid dies.

For a raid 5 and 6 the parity is distributed across all drives, its just easier to understand the concept if i break it into 2 real drives and a hypothetical parity drive.
 
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He does have a local backup as mentioned a few posts ago.

In fact he used to have 2 local backups until 1 died.
 
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RAID 1 + 5 drives.
There are worse ways to waste money and drive space. Not many, though.


I have a 4 bay NAS box. 4 x 4TB Ironwolf drives. RAID 5. Approx 10.5TB effective drive space. It will survive the loss of any single drive.
I also have a full backup of the full data set (done weekly), on a whole other 8TB drive. Just in case the NAS box dies or other foolishness.
 
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Hard copies can be stolen or lost during a flood or have coffee spilled on them.

You could always tattoo the decryption password on your inner thigh 😛

Or just have the decryption password stored in a separate email account unrelated to your current one.
That way some one would need know about both accounts and hack both accounts to get access to your important data

 
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Wouldn't it be easier(maybe less expensive) to just swap out a drive rather than buying a new external drive if the device goes dead, assuming you have a reliable RAID controller and power supply? Well that was my thinking anyways when I saw hardware RAID enclosures....

So I am to acknowledge that RAID1 does not require an even number of drives and it all comes down to whether the RAID controller supports it or not? Do you know of any external RAID enclosures that can do odd number of drives in RAID1 setup? Are there any reliable hardware RAID enclosures you know of?

That's painful watching your data go through like that, even at 500KB/s.....I would have lost it after a day....hahahaha :lol:

I know RAID1 by *itself* is not a backup, but I did mention I have copies outside of my master device....one of which copies that is on an external device just died...I took it out of the enclosure, plugged it into my computer and sure enough it powers on, albeit with some clicking-like noises(I can upload an audio recording of it if you want to verify this is the click of death or just the drive's usual operational noise...lol)....but at least it powers on....chucked it back into the enclosure, connected the USB3.0 cable to the enclosure and computer and 12V supply to the wall and nothing happened, tested the power supply on the other working expansion drive and powers that fine, so that would leave me to believe the expansion controller PCB died quietly.....which means I will either need a replacement PCB and keep using the same drive it came with until either this replacement PCB dies too or and the drive dies OR decide on a new external backup solution and yeah, you've mostly likely already read that above....

And this would be....?

I was going to link where I found this guy talking about how RAID 5 and 6 induces UREs, but I can't find it anymore.... 🙁 Probably because it's late at night now and I can't think/see properly due to fatigue.... but yeah, from the top of my head, he said something like "I would go RAID 5 and 6, but they increase the amount of UREs, hence I'm sticking with RAID 1" or something like that...a bit fuzzy my memory on that but that's basically the gist... maybe it was just my imagination....? :/ Hmm, so I searched up RAID 5 and URE and maybe I must have confused it with the fact that it's less tolerable with UREs than RAID 1 is.... Anyways, might come back to that tomorrow when I wake up...

Ahhh, that's a much easier concept to know how you explained the way RAID 5 and 6 work - I was reading all this on wikipedia and various other sites explaining it in detail with a wall of text and or pictures trying the grasp what the hell 5 and 6 does, but you just dumbed it down without all those long technical terms and illustrations.... I like! :) Where's the thumbs up emote when I need it here??! Thanks! Can you do this for RAID 2, 3, 7, 8 and 9 if they exist, please? 😀

So if I got this right, RAID 6, if using your example, would be equivalent to 5 + 8 + 2 = 15? So RAID 5 and 6, calculates what the final figure is and if they know that, they can work out what *should* be the other values that add up to the final value, in this case 15? If the drive with the data "2" and another drive with the data "8" dies, how does it know that it's 8 and 2 that are the missing values that adds up to 15 and not 9 and 1 or 5 and 5? Also, if a drive fails in either RAID 5 and 6, there goes part of my data too(but can still access data that's on the other drives?)? So I would need a replacement drive ASAP before I can access the data that was lost on the failed drive?

Yeah, that's also another reason why I chose RAID 1 over the others, because I didn't quite yet fully understand how the other modes work(I knew RAID 10 and RAID 01 but since I didn't quite care much for performance and rather be protected the most from drive failures, I chose 1), so for all I know, they could be worse than RAID 1 for my situation!

Isn't that called a copy? I thought the term backup requires a minimum of two copies(not including the master source device)....so you would need another 8TB drive or another NAS box, on standby too.... :??:

 
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Backup.
A second copy. Or 3rd, or 4th.

So in my realm, the PC's are backed up nightly to the NAS.
The NAS also hold some stuff all on its own. Movies, music.
There is also a weekly backup of the entire NAS.

So everything exists in at least 2 places. Sometimes 3.
For critical stuff, in a 4th location...a drive sitting in a desk drawer at my office.


A RAID 1 is solely for continued operation in case of a drive fail. The data still really only exists in one place.
If you delete something...it is gone. Just gone from multiple physical drives at the same moment.

Virus, malware, ransomware, lightning strike, fire, flood, theft...RAID 1 does absolutely nothing for those fail modes. Which are all far more likely than a dead drive.

Your 5 x HDD + RAID 1 is exactly as susceptible to ransomware as is a single drive.

If my PC melted into a pile of goo, all that data still exists on the NAS in the backups.
If the NAS melts down, data still exists on my main PC, or in the NAS backup.
If my PC and the NAS both die....the backup of the NAS.

In the case of a major fire/flood...anything really critical also lives on the drive at work. Scans of passport, drivers licenses, birth certs, etc.
But in that case, I have many more things to worry about other than simply losing a bunch of movies.

Of my main systems, there are 8 drives. All SSD.
If any one of them were to die, I'd simply slot in another drive (either HDD or SSD), and recover from last nights backup. Take maybe 20 minutes. I can live with a 20 minute downtime.

For a more detailed explanation of my personal backup scenario and layout, the first post here:
http://www.tomshardware.com/forum/id-3383768/backup-situation-home.html
 
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If a drive in a 3 disk raid 5 breaks it works almost exactly like that simple 8 + 5 = 13 from earlier.

If drive 1 that held the 8 were to die you would put in a new blank drive to replace it.

The rebuilding process would look like this, x + 5 = 13.

With the raid controller solving for x for each individual sector on the hard drive and writing the resulting value to the new hard drive, restoring the raid.

The key word here is distributed parity meaning any drive can fail and you are still good.

A much older raid called raid 3 has something like you were thinking, a dedicated parity disk.

But it was replaced with raid 5 due to being more resilient.


Heaven forbid my whole house turns to "pile of goo" / fire / flood, i know all of my files are safe on the Crashplan servers.

They even store multiple copies of my files in case of a ransomware as USAFRet mentioned.

I wouldn't rely solely on cloud based backup but its an awesome form of secondary backup in case the worst happens.
 
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Except with Crashplan, et al...you are subject to the whims of their business plan.
Like this:
CrashPlan for Home being discontinued, refers customers to Carbonite
CrashPlan is shutting down its cloud backup service for consumers
Crashplan drops its cloud backup service for home users
 
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And the ship as set sailed off to the horizon....never to be heard from again...unless you have a business with them.

OK, so to clear my head of any misinformation I read/heard(Or even interpreted incorrectly), RAID1 is this(using a reference picture of HighPoint RocketStor 6114V): https://imgur.com/ywvAsOO

Can RAID1 be spanned over more than two drives at once, so the middle and right pictures or can it only be done in duos in which case I would have sets of RAID1 drives as is illustrated on the left image(in which case it might just be cheaper if I just go buy a two bay RAID1 enclosure rather than a 4 or more bay RAID enclosure...)

[strike]And can span as many drives as possible, you can pick the number of drives you want it to span over or it can only span two drives at any given time, meaning if I were to say get a 10 bay RAID 1 setup, that would mean I would have 5 RAID 1 drives to deal with instead of 1 drive that's spanned across all 10? Or does it depend on the mode/brand/RAID controller of the enclosure? [/strike]
 
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A single RAID 1 array can contain 2 or more physical drives.
As the far right thing in your image shows.
https://en.wikipedia.org/wiki/Standard_RAID_levels#RAID_1

For instance, my 4 bay Qnap NAS can do a RAID 1 across all 4 drives if I choose. Obviously, this is a massive waste of drive space.
4 x 4TB drives + RAID 1 = 4TB actual space.
Currently, I have those 4 x 4TB drives in a RAID 5. With ~10.6 usable drive space. It will survive the loss of a single drive. And yes, I've tested this.
 
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Solution


Yes! definitely, you can have FIVE HDD with same data, all 5x drives are identical
Get this box
http://www.datoptic.com/ec/esata-usb31-driver-less-hardware-raid-support-mac-windows-freebsd-linux.html

Yes I used this to duplicate HDD 1:5 copying

 
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Sorry, never even got a notification email that someone replied...thought the thread was dead...until I physically logged into the forums and checked today to bump the thread, but instead I found there are two replies since then!:ouch::??:
:/ Notification system must be bugged...

Anyways...

AHh, perfect, so it is possible and answers my question, thanks; just need to find a brand and model that actually implements it....guess I'll be skipping the HighPoint RocketStor 6114V since it can only do it in pairs...

If 4 x 4TB drives in RAID 1 is a massive waste of drive space, I wonder what 5 x 12TB drives in RAID 1 is called...? :lol::sarcastic:😛😀

OOooooooooooooooooooooooooooooohhhhhhhhh.......are these guys any good? Is this the box you're still currently using too? Or have you moved on? So this box can do a single RAID 1 volume of five drives? Any others or is this the only one that can do more than a pair of drives in RAID 1 on only one volume?

[strike]Ooh, how about this one: http://www.datoptic.com/ec/esata-usb3-0-raid-jbod-five-sata-tray-less-hardware-driver-less.html ?[/strike] Oh, someone already asked in the Q&A page and that box can't do one RAID 1 volume of all five drives...also it's RAID controller is limited to revision 2 of SATA, so tops out at 300MB/s....rather than 600MB/s from revision 3....not that it matters that much for HDDs(until we break the 300MB/s read or and write speeds for mechanical drives...), though you never know when I might decide to chuck in SSDs instead of HDDs in future, provided that the box is still alive then! 😛 oh yeah, and it's also only USB3.0, not USB 3.1 as is the one you quoted, 10Gb/s transfer rate does sound like a nice figure....faster than gigabit network!😀 Though includes overhead to convert the signal from SATA to USB which is then converted back from USB to SATA, where I can just hook it up with eSATA and have passthrough with no overhead conversion, but would be limited to 6Gb/s, assuming the RAID controller on this box supports revision 3 of SATA....

Just a thought, from looking at the picture from amazon(and one somewhere else), it appears to have better cooling capacity(Dual fans vs. single fan) and maybe a compatible replaceable PSU with a standard ATX one if the thing dies after warranty period...that it would be a better pick, despite the higher cost... I suppose the LCD panel display is a bonus...?
51Vr2tUVcFL.jpg

58880t450.jpg


So I guess, nevermind that suggestion...
:/

So, I've done some research and how do these other boxes compare?
http://www.ebay.com.au/itm/ORICO-Aluminum-5Bay-USB-3-0-3-5-Inch-SATA-Hard-Drive-Disk-HDD-Enclosure-Raid-Box-/252996480767
http://www.ebay.com.au/itm/ORICO-Aluminum-5Bay-USB-3-0-e-SATA-3-5-SATA-Hard-Drive-HDD-Enclosure-Raid-Box/252996480447
http://www.ebay.com.au/itm/ORICO-Aluminum-4Bay-USB-3-0-e-SATA-3-5-SATA-Hard-Drive-HDD-Enclosure-Raid-Box-/252835332456
http://www.itsdirect.com.au/com_products.php?view=detail&category_id=86&sub_category=614&Product_ID=31853&utm_source=staticice

These were the only higher than three(but less than six) bay hardware RAID external enclosures with either USB or and eSATA interface I could find in my region...
 
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The question was:
Can you have 5 drives in RAID1?

Yes, you can have more than 2 drives in a RAID 1 array. The word 'mirror' is meaningless.
 
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you can do it, but normaly that many drives would be configured in a raid 5, 6, or 10 array, or a 0 if your feeling rebellious and back up the drives on a weekly basis. I could see an advantage to that however. If you mirrored the data across 5 drives with one serving as the primary until that one fails, then you have 4 failures the raid can withstand before it goes kaput after the last failure. Try it for yourself man. As Miss. Frizzle from "The Magic School Bus" always says "Take chances! Make mistakes! Get messy!"
 
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