RAID5 - starting with one drive

xrapidx

xrapidx

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My data is becoming an issue to me, its all over the place, on various different sized drives... and I'm out of space again :(

Tomorrow I'm buying a 2TB drive, and at the end of the month will be buying another 2x 2TB drives....

What I'd like to know, is it possible to create a RAID5 array without loosing the data on the first drive using the three above drives? (or is this going to be hardware dependent)
 
No, all data is lost when creating the array...
 
...dammit... and I'm assuming you can't create RAID5 with only two disks (effectively a mirror)...
 
xrapidx said:
My data is becoming an issue to me, its all over the place, on various different sized drives... and I'm out of space again :(

Tomorrow I'm buying a 2TB drive, and at the end of the month will be buying another 2x 2TB drives....

What I'd like to know, is it possible to create a RAID5 array without loosing the data on the first drive using the three above drives? (or is this going to be hardware dependent)
Click to expand...

Not possible
 
At least 3 for RAID5, 4 for RAID6

A RAID5 3-disk array can survive the failure of one disk, but that's that. RAID6 can survive the failure of two disks.
 
Linoman said:
No you need at least 3
Click to expand...

That's what I thought :( pity... so I'll have to save and buy at least three drives at a time.

The_Librarian said:
At least 3 for RAID5, 4 for RAID6

A RAID5 3-disk array can survive the failure of one disk, but that's that. RAID6 can survive the failure of two disks.
Click to expand...

Yip...studied it about 10 years back :p a bit rusty... was hoping I'd be able to hack it somehow... didn't even think of doing RAID6, not sure if its necessary though... what are the chances of two disks going at the same time (famous last words :p)
 
you can create three partitions and have them RAID'ed :p

Not gonna help if the whole disk crash and burn though.

Best to buy one drive now, put it away, then the next month buy another, put it away, and the 3rd month buy the final disk, then build the RAID.

That way you get drives that are not from the same batch.

Problem is if you buy a lot of drives at once, they might all be from a faulty batch...
 
The_Librarian said:
you can create three partitions and have them RAID'ed :p

Not gonna help if the whole disk crash and burn though.
Click to expand...

I've actually seen this done in a production environment for a small financial company... :wtf:


The_Librarian said:
Best to buy one drive now, put it away, then the next month buy another, put it away, and the 3rd month buy the final disk, then build the RAID.

That way you get drives that are not from the same batch.

Problem is if you buy a lot of drives at once, they might all be from a faulty batch...
Click to expand...

But... I have around 3GB free across around 10TB of storage :p I'm out of storage (and money :p) :(
 
One device that does that is the Drobo.

I read a whole blog post pertaining to this which convinced me that simple mirroring is the bst: basically in raid-5, if one drive fails, the rest of the raid array needs to be reconstructed with an identical drive before you can get your data back. If any more drives fail, or something goes wrong then you're screwed.

With mirroring, if a drive fails you're still good to go.

Expansion can be performed in pairs, adding two drives at a time. These days storage is cheap. A 2tb drive is peanuts. Compared to the value of the data it contains.
 
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Remember that RAID does not equal a backup.
If I were you I would look into getting an HP NL36 Proliant Microserver, adding a few hard drives (up to six possible with some modding, ie. eSATA to SATA cable and extra SATA power connector) loading FreeNAS (http://sourceforge.net/projects/freenas/files/FreeNAS-8/) onto it and be done. Least hassle in long run. Remember to keep important files (photos, etc) in at least two separate locations.
 
Synaesthesia said:
basically in raid-5, if one drive fails, the rest of the raid array needs to be reconstructed with an identical drive before you can get your data back.
Click to expand...

It doesnt have to be an identical drive. Must just be the same size or bigger. If you have 3 x 1TB drives setup in raid5 and 1 drive fails, you can replaced the 1TB drive with a 2TB drive (Only 1TB of the drive will be used in the array and you will have a extra 1TB unused)

With mirroring, if a drive fails you're still good to go.
Click to expand...

It all comes down to cost per GB. With a mirrored system you are wasting one drive, with a 3 drive RAID5 system you are wasting 1 drive (1/3). With 4 drives (1/4 etc)
 
Exactly- I want to work my way up to 8x 2TB drive - starting at 3 - so was wondering if its possible with the above device.
 
I would gofer a raid 6 setup with that. You get software and hardware raid. I recommend software.
 
i was looking at this(http://www.lime-technology.com/) solution a while ago, and it seemed to do exactly what you need - ie able to protect the data and grow without losing the data
you can choose to just buy the software....and then have it as a networked media server somewhere in the house :P
i only chose to use ubuntu rather, because it seemed to be rather a b*** to customize the linux provided with unraid. trial versions of the software was available as far as i remember to allow up to 3 disks.

currently i am using - hardware RAID-6 ( ouch $$$ :( ) and a software raid-5 ( which ubuntu was able to grow from 4 disks to 10disks without affecting data - very cumbersome process though, but stable as hell)
 
Too bad you're in CPT, I'd have helped store your data during the cross over period. Got quite a few TB's free space at the moment
 
gregmcc said:
It doesnt have to be an identical drive. Must just be the same size or bigger. If you have 3 x 1TB drives setup in raid5 and 1 drive fails, you can replaced the 1TB drive with a 2TB drive (Only 1TB of the drive will be used in the array and you will have a extra 1TB unused)



It all comes down to cost per GB. With a mirrored system you are wasting one drive, with a 3 drive RAID5 system you are wasting 1 drive (1/3). With 4 drives (1/4 etc)
Click to expand...

The effective price versus performance hit comparing RAID5 and RAID10 makes RAID10 far preferable when it comes to drive loss,but I guess for home users you'd rather pray 1 drive fails and can be rebuilt before anything else happens to the array and lose 1/3 to 1/4 of your total storage capacity to striping,versus 1/2 for Mirrors
 
As for OP Topic,Considered using Windows Home Server? ( NOT 2011 )

WHS had this lovely nifty little feature called Drive Extender
Windows Home Server Drive Extender is a file-based replication system that provides three key capabilities:[12]

Multi-disk redundancy so that if any given disk fails, data is not lost
Arbitrary storage expansion by supporting any type of hard disk drive (Serial ATA, USB, FireWire etc.) in any mixture and capacity
A single folder namespace (no drive letters)
Click to expand...

Plug in new drive,add it to existing storage,done

They dropped it from 2011 :mad:

As a note,there are addins for 2011 from 3rd party vendors to provide Drive Extender capabilities
 
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sorry for necro.

But the time has come, my microservers are dropping dead like flies.

Could someone explain what happens in an unraid setup if I have three drives and one dies - do I loose ANY data?
 
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