First RAID attempt, need quite guidance...

[MrPatate]

Hi,

I've got two questions.

I currently have two 500GB WD RE2 running normally (not raid), One for data, other for backup. They are full and I'm going to buy a new HDD 1TB. So should I keep my new drive for data and put the other 2 in RAID for backup or the opposite? Which one of these setup is going to be most reliable and fast(reliablility is the most important thing I want).

I'm hesitating between 3 model of WD 1TB (Green, Black and RE3). Like I said before, reliability is the most important thing, speed is also important and I don't really care about energy saving (so the Green is out, unless there's something special I don't know). But I don't remember the price difference between RE2 and the "normal" serie to be so big (its the only reason I'm hesitating to buy RE3 right now since I'm at school).
In the futur, I'll probably build a WHS or have a NAS, and could easily transfer the 1TB in it with a second one. So what do you suggest about the new drive?

Thanks

 

[DonDon]

Western Digital RE drives should ONLY be run in a RAID environment that has redundancy. Such as RAID 5 or 6. They should never be run in stand alone mode because you risk data corruption. TLER, the main technology that makes them RE drives limits the time that the drive will attempt to recover from errors. In a redundant RAID environment, the RAID will handle the serious errors. In a desktop system, it will simply stop trying to recover from errors after 7 seconds and leave you with corrupt data.

Just because you have been running for a long time does not mean you are safe. In fact, just the opposite is true. Sooner or later, the drives will need to recover from a serious read error and will not be able to.

That said, looks like your best bet is the Black drives then. But, unless you are using them for your OS drives, the Green drives are plenty fast enough for any reasonable storage task. Do not get the RE drives unless you are setting up a Raid array with data redundancy.

There is a utility to turn TLER on and off. So if you get desktop drives now, and want to build a RAID array later, you can always turn TLER on then. I am running 3 desktop drives in my NAS with TLER turned on. That's how I found out about TLER. Of my original 3 drives, 1 kept dropping out of the array. I RMA'd it, and while I was waiting for the replacement, I did some research on the problem and discovered TLER.

Don

 

[MrPatate]

Western Digital RE drives should ONLY be run in a RAID environment that has redundancy. Such as RAID 5 or 6. They should never be run in stand alone mode because you risk data corruption. TLER, the main technology that makes them RE drives limits the time that the drive will attempt to recover from errors. In a redundant RAID environment, the RAID will handle the serious errors. In a desktop system, it will simply stop trying to recover from errors after 7 seconds and leave you with corrupt data.

Just because you have been running for a long time does not mean you are safe. In fact, just the opposite is true. Sooner or later, the drives will need to recover from a serious read error and will not be able to.

That said, looks like your best bet is the Black drives then. But, unless you are using them for your OS drives, the Green drives are plenty fast enough for any reasonable storage task. Do not get the RE drives unless you are setting up a Raid array with data redundancy.

There is a utility to turn TLER on and off. So if you get desktop drives now, and want to build a RAID array later, you can always turn TLER on then. I am running 3 desktop drives in my NAS with TLER turned on. That's how I found out about TLER. Of my original 3 drives, 1 kept dropping out of the array. I RMA'd it, and while I was waiting for the replacement, I did some research on the problem and discovered TLER.

Don

Thank you for your help.
I've got a Raptor for my OS, those drives are purely for data storage and active downloads (torrent). I didn't knew about TLER, I'll turn it off since it's goind to be in RAID 0. What do you suggest for the futur configuration, backup on the RAID or on the 1TB? I know they will both work, but one might be better than the other.

 

[MrPatate]

The only thing I can find on WD site is this Data Lifeguard Tools 11.2 for Windows and it doesn't seem to disable TLER. In a post, someone asked if it's possible to disable TLER and a WD rep. gives a negative responds. On google I can only find some old threads with dead links of the utility (I suppose it's an homemade utility, since WD doesn't have it!??)..

 

[DonDon]

The only thing I can find on WD site is this Data Lifeguard Tools 11.2 for Windows and it doesn't seem to disable TLER. In a post, someone asked if it's possible to disable TLER and a WD rep. gives a negative responds. On google I can only find some old threads with dead links of the utility (I suppose it's an homemade utility, since WD doesn't have it!??)..

Oops, should have given you this LINK!

Not sure where I found it though. Dig a bit and you should be able to get it.

Don

 

[MrPatate]

Western Digital RE drives should ONLY be run in a RAID environment that has redundancy. Such as RAID 5 or 6.

Oops, should have given you this LINK!

Thank you for your help.

You say it should only be enabled on a RAID with redundancy. But in wikipedia, its mentionned that it's better to have it enabled with anykind of RAID to prevent HDD to be drop from the array.

I intend to do a RAID0 (with backup on a 1TB WD Black I just received), should I disable it since in RAID0 there's no redundancy and recovering from an error is more important than an HDD drop? Or does adding back an HDD is more trouble, as more chance to loose data and isn't worth it compared to the lost of a "single" file(s)??

 

[DonDon]

Well, everything I read about TLER on the Western Digital Website says that it does you no good to have TLER on if the array does not have data redundancy. So, it really doesn't matter in RAID 0, cause if the array cannot fix the bad data, you are hosed.

RAID0 should not be used for critical data. You are better of without TLER in RAID 0 cause the drive may be able to fix itself before the array times out.

Don