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[rshah]

I understand how RAID1 works.  However, I'd like to confirm that it's working and my files are being mirrored.

I have two 1TB WD Green HDDs.  I'm storing data on Volume_1.  Theoretically, Volume_2 should contain all my mirrored data.  How can I confirm this?

The D-Link tech on the phone said the only way to do this is by pulling out Volume_1 (i.e., simulating a HDD failure) and inserting a new HDD in that slot.  Then, my data should magically appear on the new HDD courtesy of the mirrored data on Volume_2.

Any ideas?  Is there a better way to confirm that RAID1 is actually working?

[Chill]

Another test is rather risky so be warned.

Pull one of the drives. Format the pulled drive (ntfs, or ext2/3/4 from another source like a PC or external enclosure,  doesn't matter)to simulate HDD failure. After reformating the drive, put it back to the NAS. Reformat the drive again using the NAS UI. Mirroring should start to kick in after the format is complete. Verify that the data is actually mirrored to the other drive.

Did I mention that this is rather RISKY? Yup, I did.

[fordem]

I'd say neither the D-Link tech you spoke with, nor Chill, have the right idea.

You want to know if RAID1 works - here's how you do it.

Pull a drive - can you access the data from the remaining drive?  If yes, then it works, If no, then it doesn't.

It's that simple.  Really.

RAID1 is about redundancy, about making sure that the data continues to be available, even though a drive has failed - NOTHING MORE.

Yes, most RAID systems make provision for automated rebuild - BUT - automated rebuild is NOT, REPEAT NOT a requirement of RAID1, it is desireable (as is hot swap), but if your RAID subsystem, requires you to power the system down, physically swap the failed disk, power back up, execute half a dozen commands, so be it.

Oh rshah - one more thing - if you can see a Volume_1 and a Volume_2, then you just might not have a RAID1 array - if you created a RAID1 volume using all the available space, you should not have a Volume_2, if you created a RAID1 volume using a part of the available space, you will have a Volume_1 that is RAID1 and a Volume_2 that contains the remaining space in a JBOD volume, and the data on Volume-1 will not be mirrored to Volume_2 unless you do so yourself.

[rshah]

Thanks for that clarification, fordem.  That made complete sense.

Yes, I do have Volume_1 as RAID1.  Also, I see Volume_2 as JBOD, but only for the 18MB that I allocated to it during the Setup Wizard process for the DNS 323.  I didn't really want it, but the Setup Wizard was asking me for it.

When I map and navigate to the Volume_2 drive, I don't see any data in it.  Also, I just see the size as 18MB.  Does this mean the remainder space is being used for mirroring?

Here's a screenshot of what the DNS 323 management console shows me for my drives.

[D-Link Multimedia]

I assume you mean 18 GB in your post, it looks like you have a 974GB Raid 1 partition (volume_1) which is mirrored data, and a 18gb JBOD partition (Volume_2) which is NOT mirrored.

Data in Volume_1 should be safe. If there is nothing in Volume_2 and it is unused then its nothing to worry about. Very strange that it made you make a small volume.

[rshah]

So is the the data in Volume_1 is being mirrored to Volume_2?

[fordem]

So is the the data in Volume_1 is being mirrored to Volume_2?

No - Volume_1 IS the mirrored array, Volume_1 is a logical disk, it's a name - the data in physical disk 1/Volume_1 is mirrored to physical disk 2/Volume_1

[rshah]

fordem,

You're a genius.  That makes sense now.  I've been misinterpreting Volume_1 has the physical disk.  So what I'm seeing as Volume_2 is actually the left-over space I didn't allocate to RAID1.  And the RAID1 that I did allocate is all of Physical Disk 1 and (Physical Disk 2 - leftover).

fordem: are you looking for a job?  I know a bunch of companies that could use your expertise!  Thanks for all your help.

Also, I'm wondering if you can help me on my other question as well:
http://forums.dlink.com/index.php?topic=6420.0

[fordem]

rshah - I had this teacher who used to tell us that genius was 1% inspiration & 99% perspiration - in this case, it's experience, I've been working with RAID and mirroring from the late '80's