Migrate raid 1 to raid 5

[itchiTriGgeR]

Hello everyone, I currently have 2- 3 Tb WD reds with all my media and junk in a raid 1. 2 Tb's are full so I am going to buy 2 more of the same drives to expand my array. My question is how can I add them to make it 4 discs and convert it to a raid 5 to be more efficient with disc space. Windows is handling the array right now but I don't mind buying a raid card if it makes sense to do it. Or should I keep it a raid 1. How can I add the discs to it? Thanks

 

[ChristineBCW]

RAIDs are a file-writing-and-reading system. Fairly base-level operations to a hard-drive.

There are perhaps migration levels from one RAID to another but I've never seen a good one. I never even try. When I want a 'migrate', I accept that I'm wiping out and starting from scratch. That's the approach I'd have you consider.

You said that you've got 2tb of files, yes? So all of that COULD fit onto a single 3Tb disk, yes?

Your existing HDDs - the old ones - are worthless to use during this process because they're already RAID'd. I assume you've got one more SATA connector available on your motherboard, and then I'd install a new HDD and copy all 2Tb of files to that one.

Then disconnect/remove it. This is your "File Bearing HDD" from now on.

Then, install the 2nd New HDD and now you've got 3 installed.

You can wipe out the first two, and create the new RAID5 array across 3 disks.

Once that's done, reconnect the other new HDD - the one with all your files - and copy those files onto the RAID5 arrive - those 3 HDDs.

Once that's done, disconnect that File-Bearing HDD. Now, spend some days with your RAID5. Check it out, make sure it performs. You may want to commit some bad behaviors - disconnect power a few times. See how YOUR misbehavior translates into the RAID. Have you corrupted it? WHO CARES?!! Because you've still got that File-Bearing HDD there with all the backups! You just need to assure yourself of what's likely going to happen during power-outages and any other 'bad behavior' you might inflict on this PC.

Once you're happy with the RAID5 performance, now you can add that last new HDD (the File Bearing one) to that RAID5. This will wipe it out, by the way. And this will take some time - count on a day, maybe overnight and a day. Just let it sit there and come back in two days and test it again. (Not that there's anything you can do about it - all of your backups are gone!)

But you'll end up with a 4-drive RAID5. With a capacity of 3.

Now, if I wanted to be safe, I wouldn't buy 2 HDDs. I'd buy 3. And that extra one would be my "File Bearing HDD" for weeks and months - maybe forever. Because if one of those new HDDs fails - or one of the old ones - then I'd have a Truly Model 'cold drive' as a replacement. (RAID drive fails can happen over time, yes, but usually they'll fail early in their 'life' - within days or weeks.) As for RAID cards, if you want good ones, think "$300+" and if that's not palatable, try the motherboard's version - I assume that's what you're using for your current RAID.

There's also a great comfort in additional backups, though.

 

[itchiTriGgeR]

That's a pretty awesome explanation that I a tally understand. Except for for thing... Once I have a 3 disc, raid5 with no data on them, I introduce the 4th with the data. How do I do that and make the 4th disc be part of the raid? Either way, I think k I will take your advice on leaving the 1 disc as a hard backup. I'll get 3 more 3 Tb drives- create a 4 disc raid5. Then just copy the info to it. Is there any way to add drives later to a raid to expand it? As far as a raid controller, I don't want to use the motherboard for 2 reasons. 1 it's slower than dog poop with a raid 5 and 2- with the Asus Sabertooth Z87, if set up a raid on the chipset, every Sata connector is now in the raid and not just the ones I want. I have 3 SSD's that are for boot and games.
The raid I want for just media and torrents and all that stuff.
Is there any specs that the raid card should have? I know nothing about raid cards. Thank you so much for the info.

 

[ChristineBCW]

Oops... there's a missed understanding.

1. Make a backup onto a New HDD ("the file-bearing" or backup data HDD)...
2. Disconnect it.
3. Install the 2nd New HDD.
4. Wipe out RAID1 and create RAID5 on the 3 HDDs - the two old HDDs, and this 2nd New HDD (Step 3's).
5. Re-connect Step 1's File-Bearing Backujp HDD, BUT NOT AS A RAID disk.
6. Copy its data onto the 3-Disk RAID5 array.
7. Disconnect this File-Bearing/Backup HDD (like you did in Step 2. I leave mine inserted in the computer, just disconnect the cables.)

Now, you have a 3-disk RAID5 array with the old data.

Eventually, you will add this File-Bearing Backup HDD as a new 4th Disk on the RAID5 using the "ADD NEW DRIVE" option. This will take some time to migrate a 3-disk array across 4 disks.

I have 4-, 5- and 6-disk RAID5s. (Anything more than 4 disks should be cause to get a good RAID controller, though. Some motherboard claim support but I've never tried it. By that time, I might have a $1,000 worth of hard drives and I think a good RAID card is a justifiable expense at this point.)

One issue you'll have with all motherboard RAIDs - they lack a "certainty" of transferability. Future motherboard controllers may or may not treat your old RAID5 disks properly. You'll never know it until it's too late.

Having a separate card gives me MORE certainty of RAID5 longevity across different motherboards.

Your alternative to 'transferability' however may be the future HDD storage capacities. This 4-Drive RAID5 will give you a good ceiling of about 10Tb of data. You may, in the future, decide to buy a few 10Tb drives (4 or 5?) and use one of those as your File-Bearing Backup HDD!

 

[stevech]

On RAID: We all preach "RAID Is Not A Backup"