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ajac63

Can I use one big drive as a RAID

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LoneWolf

Can I partition a large drive into multiple logical drives and set that up as a RAID instead of having multiple smaller capacity drives?  I know of course that Windows allows you to divide-up a drive this way, but no idea if you can have that as a RAID system.  That's basically it.

 

RAID is used for either redundancy (RAID-1/5/6/10/50/60) or speed (RAID-0).

 

If you have no redundant disks, you have no RAID.  Suppose you could manage to partition a drive in half and mirror.  If something went wrong with the drive, it would go wrong totally.  This is why you need at least two disks for redundant RAID.

 

If you were going for speed, same issue.  RAID-0 is for striping data for faster reads across two disks.  Say you could stripe across two partitions on one disk.  You'd have the limitations of one disk, namely that the heads would have to seek to two place on one disk (instead of two sets of disk heads).  So, no advantage.

 

The very definition of RAID is (depending on what time in history you look at it) either "Redundant Array of Independent Disks" or (earlier) "Redundant Array of Inexpensive Disks".  Without more that one disk, you wouldn't have the Redundant.

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LoneWolf

I know one drive can't be a true RAID setup, I was just curious if it could be done in theory.  I think what I want is a simple second-drive for commonly shared data that is automatically backed-up to an external backup drive.  RAID 0 seems unsafe, RAID 5 is safer but you seem to lose some capacity going by clips on YT and elsewhere that I've watched.

 

Note that RAID-0 isn't meant for safety; it is meant for speed.  And with RAID 1/5/6/10/50/60 you will always lose capacity in favor of redundancy.

RAID is never a substitute for backup, at any rate.  It is for data continuity.  Example:  If you have a RAID-1 mirror, and you corrupt a file on Drive 0, then Drive 1 will mirror the corrupt file.  If you delete a file on drive 0, the deletion will be mirrored on Drive 1, and you won't be able to get the file back.

 

RAID allows you to keep your system running with limited or no downtime (depending on whether your server has hot-swap capabilities) while you replace a failed drive.  However, RAID arrays can have more than one disk fail at a time, rendering the array unusable, which (in addition to the first two examples) is why backup is still necessary.

 

It sounds like what you want is a primary drive, and then backup software like Macrium Reflect (free for home use) which can back up on a schedule, including incremental backups that only back up changed files over time that backs up to a second drive.

Edited by LoneWolf

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ajac63

You could backup the volume from one to another but if the drive were to fail, then everything is lost.  In theory kind of like RAID 0 but it is not RAID.

Yes, that would be effectively RAID 0, but if the data is regularly backed-up to another drive then not everything would be lost - as I understand it anyway.  I've backed-up my current main drive this way for years, albeit manually and not automatic back-up, but for server purposes I would o.c setup Windows to do it this way.

RAID is used for either redundancy (RAID-1/5/6/10/50/60) or speed (RAID-0).

 

If you have no redundant disks, you have no RAID.  Suppose you could manage to partition a drive in half and mirror.  If something went wrong with the drive, it would go wrong totally.  This is why you need at least two disks for redundant RAID.

 

If you were going for speed, same issue.  RAID-0 is for striping data for faster reads across two disks.  Say you could stripe across two partitions on one disk.  You'd have the limitations of one disk, namely that the heads would have to seek to two place on one disk (instead of two sets of disk heads).  So, no advantage.

 

The very definition of RAID is (depending on what time in history you look at it) either "Redundant Array of Independent Disks" or (earlier) "Redundant Array of Inexpensive Disks".  Without more that one disk, you wouldn't have the Redundant.

Very true.  I must have fallen out of bed  :rolleyes:

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ajac63

I've decided I'll get 3 or 4 inexpensive drives at 500GB each(so 1.5-2TB total) for shared data which is enough for my needs and do a RAID 5, albeit I don't like the fact that I'd lose some capacity this way.  I would have a 750GB SSD as my C: drive for the OS and apps.

Edited by ajac63

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itGeeks

I've decided I'll get 3 or 4 inexpensive drives at 500GB each(so 1.5-2TB total) for shared data which is enough for my needs and do a RAID 5, albeit I don't like the fact that I'd lose some capacity this way.  I would have a 750GB SSD as my C: drive for the OS and apps.

Make sure you use disk rated for RAID, Don't just use any old disk. WD Reds are a good choice though there are others. Green drives are not a good idea. The smallest size your going to get in the WD Reds is 1TB http://www.amazon.com/Red-1TB-Hard-Disk-Drive/dp/B008JJLXO6/ref=sr_1_4?ie=UTF8&qid=1458816259&sr=8-4&keywords=wd+red+hard+drives

 

You don't want to play when it comes to drives in a RAID setup or your just asking for trouble, Use the right hardware and chances are it will be good to you.

Edited by itGeeks
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ajac63

Make sure you use disk rated for RAID, Don't just use any old disk. WD Reds are a good choice though there are others. Green drives are not a good idea.

Yes, I'll take that advice.  Any old disk would be toooo cheapo, even for me :)   Seriously, yes, I'll make sure they are RAID rated - WD drives are v reliable.  My main desktop has a 500GB WD blue one I think, never had issues with it.

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LoneWolf

Hitachi (HGST) drives are also a good choice if you find the right ones.  I'm using WD Reds myself, but I'd also use Hitachis.  Best to get all identical drives for an array.

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