RAID 0 + Backup?

terminator363

terminator363

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Bulgaria
Canada
So as I'm getting ready for Windows 10 and a fresh install, it occured to me that I have 2 identical 1TB hard drives - of which I only really use one. I decided that if I were to use both I'd rather have them as one volume. I knew about JBOD but it didn't really provide any substantial benefit. I decided to bite the bullet and figure out what RAID was all about. After reading a bit it occurred to me that RAID 0 is pretty appealing. Now understanding the issues with reliability, can I buy an external hard drive and just backup the two RAID disks just as I would with one regular HHD? And if one of the internal disks died, could I just buy another, use the backup, and run raid again with no data loss?

:confused:
 
JBOD is not a RAID mode, it is also called span.
NEVER USE IT.
It has no benefit.

This is a rough break down of common RAID types
RAID 0 is stripe(needs 2 drives, storage space is equal to size of total HDDs, has performance increase at the cost of no redundancy)
RAID 1 is mirror(needs 2 drives, storage space is equal to the size of a single HDD, has redundancy at the cost of same performance)
RAID 5 is block stripe with parity(needs 3 drives, storage space is equal to the size total size -1 drive of all HDD in setup, if a drive fails you still have access to data, rebuild time can take ages in which time another failure might occur and if it happens all data is lost, write speed is a little slower due to writing parity but read speeds is fast)
RAID 6 is block stripe with double parity(needs 4 drives, same as RAID 5 but you have an extra parity drive for more redundancy, storage space is equal to the size total size -2 drive of all HDD in setup,, if a drive fails you still have access to data, rebuild time can take ages in which time another failure might occur and if it happens all data is lost, write speed is a little slower due to writing parity but read speeds is fast)
RAID 10 is mirror then stripe(needs 4 drives, storage space is equal to half of the total HDDs, has performance increase & redundancy)

Reason not to ever use span.

If you have 4 4TB HDDs.
You can span them to get 16TB with no benefit what so ever
or you can use RAID 0 and stripe them giving you 16TB and have the read and write speed increase.
Also if one drive fails in a span you lose all data, even if has no data written to it.


I have 4x4TB in a RAID 5 giving me 12TB to use
 
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Grayfox
RAID 1 is mirror(needs 2 drives, storage space is equal to the size of a single HDD, has redundancy at the cost of same performance)
Click to expand...
RAID 1 can, depending on how it's implemented, deliver up to about the same read performance as RAID 0, but will stay behind in write speeds.


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@terminator363
Btw, redundancy is not a replacement for backups, nor is it the other way round. These are two different concepts.
 
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Guys, I know what RAID is. I'm just wondering if I use RAID 0 (if I'm using RAID it's 0 that I want to use), can I still use a backup drive just as I would to accompany a regular single hard drive? And can I recover lost data from that backup if one of my 2 disks in my RAID array fail?
 
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You can do normal backups using any RAID like with any normal drive

As stated RAID not on RAID 0 if you lose a drive as well as RAID 5 if you don't replace a failed drive in a timely manner you lose everything.
It is a good idea to have some kind of redundancy.

If the RAID array fails and drops the drives.
You can use a program called RAID recovery by run time software, which will attempt to rebuild the RAID so you can get the data back but only if the drives work.

And with motherboard RAID controllers, you might not much of a speed increase since motherboard RAID controllers are basic and modern HDDs are fast.

Also remember with RAID systems that increase the size of the volume.

The larger the volume, the longer it will take to perform things like defrags and worst of all, chkdsk might not be able to be run on such large volumes my RAID cant run chkdsk as it easily uses 6GB+ and I only have 8GB
 
Grayfox
You can do normal backups using any RAID like with any normal drive

As stated RAID not on RAID 0 if you lose a drive as well as RAID 5 if you don't replace a failed drive in a timely manner you lose everything.
It is a good idea to have some kind of redundancy.

If the RAID array fails and drops the drives.
You can use a program called RAID recovery by run time software, which will attempt to rebuild the RAID so you can get the data back but only if the drives work.

And with motherboard RAID controllers, you might not much of a speed increase since motherboard RAID controllers are basic and modern HDDs are fast.

Also remember with RAID systems that increase the size of the volume.

The larger the volume, the longer it will take to perform things like defrags and worst of all, chkdsk might not be able to be run on such large volumes my RAID cant run chkdsk as it easily uses 6GB+ and I only have 8GB
Click to expand...
So the reason I want one large volume instead of multiple hard drives and partitions is because ever since I've been using my computer it's had 2 hard drives and a total of 3 partitions, one of which is only 50gb (C drive) and it's such a hassle moving stuff from drive to drive that I just want everything at one place all the time. (The 50GB boot/windows drive always fills up too).

I just want two drives in RAID 0 that can be backed up and replaced in case of failure with no data loss. I just want to know if that's possible.

Like if I back up a windows backup image to an external drive and one of the RAID disks fails and I replace it, can I just swap it with a brand new one, restore the backup image and keep going as if nothing happened??
 
You are better off using RAID 5 which needs 3 drives or RAID 10 which needs 4 drives if you want to have a backup and a little more performance, otherwise use RAID 1 which is mirror so an exact copy of the drive.
So no need to really back up as odds of 2 drives failing at the same time is very very rare.
 
Grayfox
You are better off using RAID 5 which needs 3 drives or RAID 10 which needs 4 drives if you want to have a backup and a little more performance, otherwise use RAID 1 which is mirror so an exact copy of the drive.
So no need to really back up as odds of 2 drives failing at the same time is very very rare.
Click to expand...
I don't want to spend any extra money on hard drives though, that's why 5 and 10 aren't really an option for me.

So back to my original question, will my solution work?
 
Well yes, but with RAID 1, you have pretty much auto back up since it is a mirror copy.
And I recommend it over RAID 1 due to data redundancy.
 
Grayfox
Well yes, but with RAID 1, you have pretty much auto back up since it is a mirror copy.
And I recommend it over RAID 1 due to data redundancy.
Click to expand...
Yea but with RAID 1 I only get 1TB total space and no performance boost. It seems like a huge loss to me.
 
terminator363
Yea but with RAID 1 I only get 1TB total space and no performance boost. It seems like a huge loss to me.
Click to expand...

These days you do not get much of a performance boost using RAID 0, 20% is the most you will get now it may seem like a large gain but this might end up being 1 or 2seconds tops.

HDDs are fast running at 7200rpm, have very good seek times.
And using motherboard RAID will only give you a small performance boost anyway.
Motherboard RAID is very basic unless you go with a high end RAID controller which will give you the fastest possible speeds out of any RAID level.
 
Grayfox
JBOD is not a RAID mode, it is also called span.
NEVER USE IT.
It has no benefit.

Reason not to ever use span.

If you have 4 4TB HDDs.
You can span them to get 16TB with no benefit what so ever
or you can use RAID 0 and stripe them giving you 16TB and have the read and write speed increase.
Also if one drive fails in a span you lose all data, even if has no data written to it.
Click to expand...

While technically true... due to the lack of striping, it seems it would be much easier to recover data from a span that has suffered a drive failure than it would be to recover data from a RAID 0 that has suffered a drive failure. In theory, only a single file in a span would have pieces that reside on both drives... and that's only if you've filled the capacity of the first drive.

Though it'd still probably not be a simple task, so yeah... RAID 0 is generally better since you get moderately improved performance from it.

To answer the OP's question, yes of course you can back it up just like a regular drive. Though naturally you'll need a 2TB backup drive if you're backing up a RAID 0 array consisting of two 1TB drives since that equates to 2TB of useable space. If either drive in the array fails, just replace the bad drive, reformat the array and transfer the data over from your backup drive.
 
Lain
To answer the OP's question, yes of course you can back it up just like a regular drive. Though naturally you'll need a 2TB backup drive if you're backing up a RAID 0 array consisting of two 1TB drives since that equates to 2TB of useable space. If either drive in the array fails, just replace the bad drive, reformat the array and transfer the data over from your backup drive.
Click to expand...

Thank you for your answer! I'm just planning on backing up windows backup images though. I'm pretty sure they wouldn't take up 2TB in total. (That's enough to recover the whole PC right?).
 
terminator363
wat?
Click to expand...

Sprase option is a function sector back up programs can deal with areas where there is no data.

Instead of having something like this.

Sector 668: No Data
Sector 669: No Data
Sector 670: No Data
Sector 671: No Data
Sector 672: No Data
Sector 673: No Data
Sector 674: No Data

It will do something like this.

Sectors 668-674: No Data

This means the 70% free space is not written into the backup image which will waste space, but it knows that you have 70% free space and which sectors are marked as free and writes this free space back when restoring the image.
 
terminator363
wat?
Click to expand...
Basically, the size of the backup will basically equal the amount of used space on the drive you're backing up.

For instance, if you back up your 2TB RAID 0 array but you've only used 100 MB of that disk space, then your backup image will be around 100 MB. If you've used all 2TB of it, then your backup will be accordingly large.

So since you're interested in using more than 1 TB, you're going to need more than 1 TB for the backup.

I'd say that RAID 5 might be worth looking into, since I'd imagine you're not equipped to be able to backup 2TB at present. You'd only have to buy an extra one of thoes 1TB drives you've got instead of having to get a 2TB one, and it would be automatically redundant without the need to manually backup, meaning that any one of the three 1TB drives can completely fail and all you'd need to do is just replace it and rebuild the data on it. All the while you'd still be able to use your computer and access all your data... although that's not recommended, since if a second drive happens to fail before you can replace and rebuild the first failed drive, your data is as good as gone.
 
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Grayfox
These days you do not get much of a performance boost using RAID 0, 20% is the most you will get now it may seem like a large gain but this might end up being 1 or 2seconds tops.

HDDs are fast running at 7200rpm, have very good seek times.
And using motherboard RAID will only give you a small performance boost anyway.
Motherboard RAID is very basic unless you go with a high end RAID controller which will give you the fastest possible speeds out of any RAID level.
Click to expand...

Keep in mind that gain would only be in large sequential read/writes too. Random read/writes might end up taking longer because he would have two drives that would need to seek. I personally wouldn't bother with RAID 0 for anything other than to learn and tinker around with RAID with. SSD's are so much faster and cheap these days.
 
Ok well from the sound of it RAID 5 is pretty good. I have similar speed to RAID 0 correct? Redundancy, 2TB available -right? All I need is one more 1TB HDD so I have 3 and I'm ready to go right?

Actually nevermind RAID 5 looks at the smallest disk right? Aka I only have 1TB of available space? That doesn't really work out for me..
 
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Pretty much all RAID setups look at the smallest disk. But what that means is that if for instance, you tried to put a 1TB hard drive and a 2TB hard drive together in RAID (0 or 1), the 2TB drive would effectively be acting only as a 1TB drive in order to match the other 1TB drive. So basically, don't mismatch different drive sizes in a single RAID array unless you like wasting space.

For RAID 5, you figure out your useable disk space by basically just subtracting a drive. So a RAID 5 array with 3 1TB drives would have 2TB useable space. And yes, it would have similar speed to RAID 0, at least when it comes to reading. You won't be getting much write speed improvement with RAID 5 though.
 
Lain
Pretty much all RAID setups look at the smallest disk. But what that means is that if for instance, you tried to put a 1TB hard drive and a 2TB hard drive together in RAID (0 or 1), the 2TB drive would effectively be acting only as a 1TB drive in order to match the other 1TB drive. So basically, don't mismatch different drive sizes in a single RAID array unless you like wasting space.

For RAID 5, you figure out your useable disk space by basically just subtracting a drive. So a RAID 5 array with 3 1TB drives would have 2TB useable space. And yes, it would have similar speed to RAID 0, at least when it comes to reading. You won't be getting much write speed improvement with RAID 5 though.
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Alright that actually sounds like a viable option. I'll look into RAID 5 and come back if I decide to use it. Thanks!
 
I get 170MiB/second write speed on my raid 5 array which has 4x4TB WD Red drives and the whole thing is connected via eSATA rather than USB3.0.
And if you want to RAID 5, you will need a RAID controller card as most motherboards do not support it.
 
Grayfox
I get 170MiB/second write speed on my raid 5 array which has 4x4TB WD Red drives and the whole thing is connected via eSATA rather than USB3.0.
And if you want to RAID 5, you will need a RAID controller card as most motherboards do not support it.
Click to expand...
My mobo supports 0,1,5,10.
 
I personlly would go for RAID 1.

Dont just think about the total size of your volume.
Having redundancy is important as a failure can happen anytime.

And since motherboard RAID systems do not report any SMART info from the HDD which means any SMART monitoring tool is useless, having your data protected is an important thing to do.

Also the larger the volume, the longer it will take to defrag it as well as perform a chkdsk on it.

Chkdsk takes 6GB of RAM when scanning my 12TB RAID system
 
Because I want to do a fresh install of Windows 10 I have around 400GB of valuable data i need to put aside somewhere before i go ahead and wipe the drives. Is there good temporary cloud storage for so much data?
 
Honestly how hard would RAID 5 be, seriously? Like if I game will I get a crazy performance drop or something? I have an i5 3570K, and it seems to be running very well.
 

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