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HDD "Standard" vs "Raid Edition" and MTBF

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November 4, 2008 3:00:07 PM

Hi, I just am a bit confused as to the benefits of the RE version of drives.

You see I am interested in buying a pair of Seagate 1.5GB drives for Raid 1 to protect my data as I am worried my drives might die (I have close to 700GB of data). Not running as a server and not 24/7, just as storage.

Are RE drives realistically needed? I'm not interested in read or write performance or things like that. Just data safety. My problem is there are no 1.5TB RE drives at the moment so if I wanted 1.5TB RE drives I can't buy anyway.

Also regarding MTBF. What does it actually tell me? The Seagate 1.5TB drive has a 750,000 hour MTBF rating. Isn't that 31,250 days or 89 years? Does that mean these Seagate drives will virtually live as long as me?

Sorry for posting again, but i posted in NAS/RAID section and no one replied after a 6 days.

Also I've only ever owned 3 drives in my life: 80GB IDE, 160GB SATA and 750GB SATA drive.

So I'm sorry if you feel my questions are noobish.
November 4, 2008 3:12:23 PM

No, The Drives will not last that long or nearly that long.

Imaging if you have 750 computers that were left running.
After 1000hrs you would expect one HDD to fail with a 750,000 MTBF.
This would be one HDD every 42 days.

RAID 1 is not a very good method to Protect Data.
There are lots of things that can go wrong.

Run the two drives independently.
Schedule a job to backup the Data from Drive 1 to Drive 2.
This way you have a backup.

If you still want RAID-1, you will still want another HDD to which you can do backups.
November 4, 2008 3:23:47 PM

ditto what zenmaster says.

the problem with raid 1 arrays is that if you suffer a software problem that causes data loss or corruption, it is gonna happen to both drives.

the raid 1 will somewhat protect you in the event of a sudden drive failure, but wont do a damn thing if some software issue goes rampant on your data.

example of a 'slightly better' backup option:

run a backup nightly, to 2 different locations on a network (2 different pc's). that way you have your data stored in 3 locations, and the odds of 3 locations failing at once are pretty astronomical. that is of course providing the building the 3 pc's are in doesnt burn down or something.
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November 4, 2008 3:51:57 PM

I like raid 6
November 4, 2008 4:12:11 PM

And one more point about RAID-1 issues not mentioned.
Let's say your RAID-1 Drive is going fine and dandy.

Then in 2 years your Mobo Fries but your HDDs are fine.

Your data is now gone, unless you buy an older mobo that uses the same raid controller.

I actually do what Michigan TeddyBear Does.
I have a number of PCs and I back them all up to a central server.
I then backup my central server to another drive.

This way my data is in the origian spot, primary backup location, and my backup's backup :>
November 4, 2008 4:26:15 PM

Thanks for those replies. I appreciate it.

Well I don't have the money for 3 PC's, just one PC.

What about I still buy 2 x 1.5TB and just manually copy the files or use a backup program. Both installed in the same PC. Will that be safer than relying on RAID?

Also can you please suggest a backup program? Or what other way do you suggest I do it? Just copy paste?

Thanks
November 4, 2008 4:29:37 PM

zenmaster said:

RAID 1 is not a very good method to Protect Data.
There are lots of things that can go wrong.

Run the two drives independently.
Schedule a job to backup the Data from Drive 1 to Drive 2.
This way you have a backup.


Ok, what do you exactly mean by scheduling? Do you mean using backup software? Kindly explain thanks.

Also any thoughts about the Raid Edition drives? Does it matter? Should I just buy the standard drives?
November 4, 2008 4:44:56 PM

ok, I will give an overview of what Zen is talking about with the backup/scheduling.

using 2 drives in your pc is an acceptable (better than raid 1) option. No, dont get raid edition hdd's, use the standard stuff for your application.

now, get some backup software (various kinds around, I use cobian (free version), and the software runs all the time, just dormant until the time I setup (in cobian) comes around. then it copies the data I want saved to the 2 different (in my case) locations on our network.

scheduling is just telling the software when you want to run the desired task.

Since you have so much to back up, I would recommend incremental on a daily basis, with 1 full backup per week. that way your pc only has to be tied up for a long time 1 day per week.

*note* your pc will have to be left on if you setup the backup time to be in the middle of the night when no one is around.
November 4, 2008 4:48:43 PM

I imagine the "Cobian" software may work.
I just schedule scripts in Windows to do this stuff.
But for most a dedicated pacakge would work best.

Here is a nice list.
http://en.wikipedia.org/wiki/List_of_backup_software

I do not endorse any particular version.

"RAID Edition" Drives are not necessary.
They may actually be slightly slower for home use.
Their BIOS is tweaked for common server tasks.

November 4, 2008 5:05:03 PM

So say i have some new files too backup, do I drop them in a folder?

How will the backup software say like Cobian know what to backup?

And if it misses a backup time because the PC is off. It will just backup the next day right?

Also will the backups have the same file created date?

I should probably read that wiki link zenmaster posted to get an idea.

Thanks for your help zenmaster and michiganteddybear.
November 4, 2008 5:25:17 PM

The answers to your questions are likely Software specific.

However, In general, if your PC is off the backup will happen at the next scheduled time. (Usually over night)

The Files SHould have the same time stamps as the original.

Usually you tell the software what folders to Backup.
For Example - My Documents.
November 4, 2008 9:49:51 PM

I like the Cobian for a couple reasons.. price is right.. and ease of use for my application..

in my case, I backup 1 folder on the machine that is running cobian to 2 other pc's on our network, and also backup another folder on yet a 3rd pc on the network to the same 2 machines I backed upto previously (backing up across the network).

the ease of use comes in when selecting what to backup, and when, its simple point and click for when, and for what and where to, simple point click/browse.

it also keeps a number of full copies (I only backup about 150 meg a nite right now) of everything backed up, then drops the oldest out of the backup set. I currently keep for 30 days.

But as Zen said, the specifics of what, when and where to backup are up to the software your using.

Nothing wrong with using scripts either as zen is, if you want to do it, and have the knowledge or tools to create them. I personally dont choose to, but could if I had to.
November 4, 2008 10:41:51 PM

ginbong46 said:
Thanks for those replies. I appreciate it.

Well I don't have the money for 3 PC's, just one PC.

What about I still buy 2 x 1.5TB and just manually copy the files or use a backup program. Both installed in the same PC. Will that be safer than relying on RAID?

Also can you please suggest a backup program? Or what other way do you suggest I do it? Just copy paste?

Thanks


This is almost exactly what a RAID-1 is. It's just manually performed. What michiganteddybear is talking about is that you want a separate location for the data. I.E. - Doesn't share as much as possible. Your power supply go up in smoke and fry everything, you lose both copies. He's referring to either backing up to a second PC in the house via network, or hook up a USB drive and back up occasionally.

RAID edition hard drives are different. RAID hard drives do not have error recovery built into the hard drive. This is good for RAID, because the hard drive tells the RAID controller and the RAID controller tells the hard drive to attempt recovery. Standard hard drives attempt error recovery on their own. In some situations the RAID controller is expecting data within a certain period of time from the hard drive. When this doesn't happen due to error recovery attempts being made, the RAID drops the hard drive from the array and says the array is degraded/failed. For 2 drives, I wouldn't worry about RAID or standard edition. But do not buy a RAID edition hard drive and then not put it on a raid controller. In that configuration, there is no error recovery in the event of problems.
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