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[brianw]

I was looking at the post at http://forums.dlink.com/index.php?topic=6215.msg80857#msg80857 and noticed that someone remarked that using RAID 1 is probably not the best way to go.  Considering I bought my hard drives at different times they still maybe in the same lot.

I was wondering if anyone has any inputs as to how well their RAID regeneration went after a failed HD?  Was it as easy as taking the old hard drive out and putting the new one in and letting the OS handle the re-mirroring??   I know that an automated file (folder) re-sync program is a lot of managing - possibly...but I'm thinking why RAID when u can file sync?

TIA 

[un1key]

ime regeneration works well but i,ve never had cause to do it on a 323,
 
Raid -0 provides higher performance and increased space for a single volume but also increased vulnerability to HDD failure as losing a single drive destroys all the data across the array

Raid - 1 provides security against a HDD failure, and is slighter faster a reads if the os supports multithreading and split seeks. It is NOT a BACKUP copy just a way of insuring access to the data on the array

Raid -5  is the same as 0 but without the vulnerabilty to hardware failures as  parity is spread across all the drives allowing a single drive to fail and be replaced without data loss

Raid - 6 as 5 but up to 2 drives can fail

as to why raid, It happens instantly in the background with no user intervention which is why it isnt a backup as any user error virus etc will affect all the data

[fordem]

I was looking at the post at http://forums.dlink.com/index.php?topic=6215.msg80857#msg80857 and noticed that someone remarked that using RAID 1 is probably not the best way to go.  Considering I bought my hard drives at different times they still maybe in the same lot.

I was wondering if anyone has any inputs as to how well their RAID regeneration went after a failed HD?  Was it as easy as taking the old hard drive out and putting the new one in and letting the OS handle the re-mirroring??   I know that an automated file (folder) re-sync program is a lot of managing - possibly...but I'm thinking why RAID when u can file sync?

TIA 

Perhaps you need to understand what RAID1 does and then you'll understand why, under certain circumstances it "may not be the best way to go" and in others, it is the only way to go, and trust me on this - file sync can NOT do what RAID1 does.

First RAID1 is NOT a form of data backup - it's about disk redundancy.

Data backup is having multiple copies of your data, so that it is not lost in the event of a problem - such as accidental or deliberate deletion, corruption due to a virus or a power outage, and yes in the event of a disk failure.  Disk redundancy is about minimizing or eliminating the downtime impact caused by a hard disk failure.

For the sake of discussion - let's say you are running a small consultancy business from your home, and you have a couple of PCs, one for you and one for your assistant and you're storing the data on your computer.  You have a big project due tomorrow and at noon today the disk in your computer crashes - you have no backup - you've lost weeks of work, and because you're unable to deliver on time, you've lost the confidence of your client.

Let's look at the same scenario now - but this time, you're syncing your computer every night to a removable disk - when the disk in your computer crashes, you connect the removable disk to your assistant's computer, and copy the files across and continue to work - you lost all the work done before noon, so you have to do it over again - you call your client and explain the situation and he agrees to extend the deadline, but he's not happy.

In the third scenario, you have the data stored on a RAID1 array, and when the hard drive crashes, you continue to work uninterrupted, deliver the project on time and everyone's happy.

Understand the difference now?

As to the question on regeneration - I've never had a disk fail on my DNS-323, but I have simulated failures, by removing a disk, with the power on & off, and on every occasion it has rebuilt the array successfully.  I've seen anecdotal evidence that where others have reported problems, but I have not experienced this personally.

[brianw]

Thanks fordem!  The scenarios have put things into a meaningful light.  I too have also see the "anecdotal evidence" around the website but am too weary and a little too busy with school to do any testing at present.

I understand the difference between RAID modes and since my data isn't "critical" per se, I was just thinking that there is more bang for the buck by NOT doing RAID in a home environment. (Why waste two 1-Tb drives when you can have 2Tb of storage as long as one keeps up with file sync.) 

I have over 600gb before I have to make the decision to break the present RAID but figured it wouldn't hurt to ask the "what if" questions now.

[mig]

I was wondering if anyone has any inputs as to how well their RAID regeneration went after a failed HD?  Was it as easy as taking the old hard drive out and putting the new one in and letting the OS handle the re-mirroring??

You have omitted one very important step in your RAID repair procedure and that is...

Before you attempt to repair any RAID, you make a up-to-date backup of your data.

Then, you have a recovery plan if you encounter any problems during the RAID repair / regeneration.
You can restore your data from your backup.  Even in a home environment, this is a big
advantage (IMHO) for RAID1 over folder sync.

But ultimately, only you can make the decision, if it is worth the cost of the extra disk, to protect your data.

[brianw]

Mig...I didn't think I was listing any steps?

Anyone that's gotten far enough in the computer world to get to this site should already know about importance of backups.

[gunrunnerjohn]

Anyone that's gotten far enough in the computer world to get to this site should already know about importance of backups.

WRONG!  You should read some of the posts here!