DSM-G600, DNS-3xx and NSA-220 Hack Forum

RAID1 works - RAID1 has only one function - to reduce and/or eliminate the down time that would occur in the event of a disk failure - you can hot unplug a drive and see for yourself - as long as your data remains available, then RAID1 has done it's job.

You apparently have your own expectations of how RAID1 should work, and the unit may or may not meet those expectations.

Different manufacturers will have different recommendations on how to restore a degraded RAID array, no doubt based on the design of their equipment - I've included D-Link's instructions below, in my simulations the procedure has worked.

The following text comes from this FAQ on the D-Link website.

Q. How do I restore my RAID1 settings if a drive has failed?

A. Note: If a RAID1 drive has failed, the DNS-323 will display the HDD LED light, of the corresponding drive, in Amber.

If this happens, follow these steps to restore the RAID1 settings:

Step 1 Power down the DNS-323

Step 2 Remove the failed drive from the DNS-323

Step 3 Insert the new drive into the DNS-323

Note: The new drive must blank with no partition on the drive

Step 4 Power on the DNS-323

Step 5 After a minute log into the DNS-323 web interface

Step 6 You will be prompt to format and resync on entry, click OK

Note: This action will format the replaced drive only and sync the two hard drives in RAID1

Step 7 Wait for format and resync to complete. The DNS-323 is now ready for use

As long as the replacement has equal or larger capacity, it'll work - there is no need for the drives to be identical or even of the same performance specification.

Part of my job involves supporting RAID arrays in corporate environments and we routinely replace failed disks with units from other manufacturers.

On my DNS-323 I've had RAID1 arrays using 1x80GB & 1x250GB - you'll get 80GB of RAID1 array and a 170GB Volume_2, I've also used 1x250GB Seagate & 1x250GB Maxtor with no trouble.

tc66 wrote:

kinda bizzare stmt that is a std hot swap SOP, not sure that is MY own expectations, this device is just NOT a hot swap

You are correct, the RAID component (mdadm) works correctly on the DNS-323, it is the hot-swap components
which do not operated correctly.  This is evidenced by the fact the device node is not freed when a hard disk is
removed.

tc66 wrote:

that is good enuff if it works when the time comes

Why wait until the "time comes" to find out?  To have confidence in your disaster recovery procedure, you should
"practice" the procedure and prove to yourself it WILL work...

So, backup up your data, and simulate a drive failure. Pull a disk, wipe it clean (just like you would get a replacement
drive from a vendor), put it back into the DNS-323 and get the unit fully RAID1 operation again.  If you have any
problem or issues write down your solutions so you can remember that when the "time comes".  Be sure to
simulate both the left and right drive failures, perhaps the recovery procedure will be different?

you can hot unplug a drive [...] then RAID1 has done it's job.

This will probably draw unfriendly fire onto me, but to be picky - I think associating hot swapping with RAID1 was initially done in the statement above.

Last edited by vedeja (2008-05-27 19:26:16)

What you describe is what it would do if you tried to create a RAID1 array with a 1GB & 1.5GB disk - I'm not certain if it will create the Volume_2 if you're replacing a failed disk.

I'll test it and let you know, but it might take me a day or two - got some other stuff that's a little more time critical

rochefort - can you see my signature?

noisuf wrote:

Thanks fordem. I currently have 2 x 1TB drives configured in RAID 1.

Let's say 1 of the 1TB drives fail in the future and there are 1.5TB drives available. If I replace the failed drive with a 1.5TB drive, would the DNS-323 automatically use the remaining 500GB and automatically create Volume_2 after resync of Volume_1?

OK - here's what I tried.

2x80GB Maxtors in a RAID1 array with about 1GB data - hot unplugged the right drive to simulate a failure and after I got the amber LED and email, powered it down and inserted a clean 160GB disk disk and then repowered it.

On logging in I got the expected offer to format the 160GB disk, which I accepted, and when the format complete screen showed up I nearly had a fit - it showed me that it had formatted two 78GB drives - Volume_1 & Volume_2 - it turns out (and I guess, in hind sight, this is to be expected) that Volume_1 was the other "half" of my RAID1 array and Volume_2 was the remaining space.

It is still syncing as I post this, but, I think I can safely say - yes - if you were to replace a 1TB drive with a 1.5TB drive - assuming they are available - it will recreate your RAID pair and make the remaining space available as a separate volume.

fordem wrote:

What determines whether a planned procedure is valid or not?  If it requires additional tools, such as fun_plug does that mean it's not valid?  If it can be done with an out of the box DNS-323 with no more than a D-Link supplied firmware upgrade does that make it valid?

Valid for is me that I can get it to work. If external tooling is needed, that is fine. I'm used to unix, and have used linux a bit. So I feel confident enough to perform all kind of actions command line.

fordem wrote:

Additional installed tools should remain intact and if you place the new drive in the right bay then should remain available for your use.

I'm not to sure what you mean with this. Do you refer to the new drive as the first new drive to install?

Anyway. I guess the best way (and safest) would just be to backup all data externally, replace the drives, and restore all the data. Including the tooling. The additional tooling actually bothers me the most. I expect that I probably tweaked the system a good bit after two years, and reinstalling all tooling is simply not convenient. That also bothers me most with my hard disk crash on the NSLU2. Most data I maintain in multiple backups, especially the data that I consider critical (pictures, and music collection :-) ). I did loose some data, but I'm not to worried about that, it's inconvenient.

I have the DNS-323 and have a problem with accessing my data.  I had 1 500 GB drive in there for a long time.  We had many power outages and I could always access the data.  I wanted more security for the data so I bought an identical drive.  I loaded it into the 2nd bay and set up raid 1.  It synced the data and things seemed fine.  I could access all of our data after the sync.  Then, we had a power outage and all of the sudden I cannot access the drives.  When I log into the NAS it asks me if I want the drives to be individual or to be in a raid array.  It says it needs to reformat the drives.  I did not want to lose my data, so I refused.  Now I cannot access the data through the NAS at all.  I tried to take the drives out and hook them directly to my PC, but when I used a partition manager to look at the drives, it said they were Linux based.  That must be why the drives show up on startup, but do not show up in windows.  I performed an integrity analysis on the drives and they are perfect. 

I am at a loss as to what to do to get my data.  I have sent them off to a data recovery company for a free analysis, but I am sure recovery through them will be horribly expensive.  Does anyone have any ideas on how I can recover the data?  Also, has anyone had a similar issue with raid failure and not being able to access either drive through the NAS?  I wanted to set up raid 1 for extra protection, and now it seems to have caused me more problems than if I had just used one drive.  My guess is this is all user error, but I don't know what to do next.

Any help would be greatly appreciated.

Regards.

Matt

I was definitely stupid for not having the NAS on a UPS, but even a UPS won't save you indefinitely (i.e. if you are not home when the power goes out).  I don't understand why the NAS won't let me access at least one of the drives without reformatting.  That is the part that does not make sense to me.  How are you ever supposed to recover if a drive goes if the system wants to reformat if the raid array fails?

As for ext2ifs, I have not heard of it but I appreciate the suggestion.  I will see what I can find online.  Is it just a file (driver) that you install on your system to allow it to read linux based partitions?

Thanks for the advice.

Matt

Last edited by fourstar77 (2008-05-29 21:01:53)

Thanks.  I will give your suggestion a try.

Windows won't recognize the partitions because they are linux ext2 partitions - I would suggest that you download and install the ext2ifs installable file system driver, which should allow you access to your data, and copy it off of that drive whilst you still can.