Problem with NAS, this may be of interest to other NAS users

I did this once by accident, also with a ReadyNAS as it happens. I shan't be doing it again. Like you I had an external back up so all was well - eventually!

Thankyou for posting!  This sort of scenario is what makes me

nervous about relying on computer based gear...there are just

so many things that can go wrong...go wrong ...go wrong!  I

have a Buffalo Linkstation with twin hard disks, mirrored.  For

the last few weeks when I turn it on, an error light is in.  It does

function correctly and I can't be bothered to begin reading once

again about the interface etc.  so I've begun to use USB sticks

to transfer music files to my SUniti.  When things get too complex

I tend to take the easy route.

lots of these problems will surface in the next few years. i have two full back up which i power up and check, each has a check card that i date on completion.    i also had contact with netgear excellent service    were does one get these premiure hard drives

I got my premium (Enterprise) hard drives from Amazon, they are designed for 24/7 operation unlike the standard disks.

Like you I will go for 2 back-ups as whilst browsing on-line following my problem I encountered a number of reports where both drives in a mirrored NAS had failed together.

Gerry 

Gerry, good write up, and all duly noted... I think your messages are

• Take a backup
• Note where each disk has come from
• Make sure you have good after sales support from your NAS vendor. 

Simon

I wouldn't classify running a NAS as particularly complicated or difficult, I just had a granddad moment. As with many things computing, such moments have a potential to cost time and data and I think this puts some people off. It was my mistake. Disasters are infrequent - even with dozy people like me - and as long as provision for back up has been made there's no harm. Apart from the grinding of teeth and wringing of garments.

• Take a backup
• Note where each disk has come from
• Make sure you have good after sales support from your NAS vendor. 

 

 

 

Simon

Hi Simon,

Spot on. 

Gerry

You are right, it was not my intention to create uncertainty regarding the use of computer based gear, just to highlight the essential admin & process involved. the problem I experienced was due to the fact that the manual made no mention of the need to retain the integrity of the Disk/Bay formation. 

I am glad I went through this process ahead of any disk failures.

Gerry

That's a good point. because sooner or later....

I've had 3 CD transport failures down the years. I've actually lost less HDDs (so far) but I'm in no doubt or under any illusions about the longevity of discs. How nice to be able to slide a new one in and continue. I've even got a spare NAS box. Anal I know. But they are relatively cheap.

Gerry - it may be useful for others in the future if you can outline the *correct* procedure for rebuilding both drives in the ReadyNAS, in the way that you originally intended.

Hi Billy,

Good idea.

Firstly it is preferable to use unformatted disks, although where the Readynas has one disk installed it should auto format the new disk to the same format.

The Readynas supports "Hot Swapping" and need not be turned off prior to removing a disk and inserting a new one. In fact it would appear preferable not to switch off when rebuilding.

The manual then notes that the first disk should be removed, it is not clear if "first" refers to the bay or just means the first step, however, I believe this is immaterial and you could replace a disk in either bay.

The Readynas will now start resynchronising the two disks, and for my 1.5 Tb of data this took around 7 hours to become fully redundant.

The next step is to remove the remaining used disk and insert the new disk into the same bay from which the second disk was removed (this is where I went wrong). This is not noted in the manuals but is very important.otherwise you get the "Corrupt root"  error that I encountered. If this happens then the Readynas needs to be  reset to factory default. Even this is not a problem provided that you can identify each disk to its original bay.

In my case as I had mixed up the disks I had to recover the data from my USB backup. It is probably worth a reminder that the Raid 1 setting with 2 disks does not provide a real backup. This needs to be a  separate process and is done easily via the Readynas with an attached USB drive. In my view you should not format the disk with the Netgear preferred option of formatting in EXT3 as you can only then view the data through the Readynas or a Linux supported facility. Fine if the Readynas is working but more difficult if this has failed.

Gerry

Rule of thumb. Don't move a disk between bay 1 and bay 2 and vice versa. 

Why have a NAS configued to RAID 1 and then back that up to a USB drive? I don't see the point.

Because Raid 1 allows a certain degree of redundancy, i.e. if one disc fails.  However, you still need a back up in case both discs fail, the NAS itself fails, it gets fried by a lighting strike etc. etc.

Your big mistake was due to the fact that the procedure was not 

covered in the manual.  I can see myself making the same mistake.

How stupid they do not cover this...and how should a normal PC or

Mac user suppose to know about formatting discs?  One can say

using a Nas is staight forward, and even I set mine up ok, but still

the minefield is there.  And you like to think that if you have setup

a two disk Nas in mirror array, that there is security there...that IS

the point is it not?!  

California Jim

^ what he said

Hi Jim,

I understand the point you are making and you could  indeed adopt a different system with a single disk in your NAS with 2 backup disks. However the Raid 1 option does an instant copy which the backup option does not do.

Gerry 

And that is exactly the danger of using RAID and why backups are also necessary.

Because when you inadvertently delete a file (or it becomes corrupted by something) it will be instantaneously also be removed from/updated on your RAID-drive as well, so there is nothing to fall back on.

Only making also an off line backup you have something to fall back on.

So there is only safety in offline backups. RAIDs are nice for hardware errors where you need to be able to have continuous access to your data and cannot afford the time to restore a backup, but they are not safe.

-

aleg

Very well explained Aleg...I had never thought of it like 

that before.  It had seemed OTT to me to DL to my Mac,

Store onto a two disc Nas...and then have to backup yet

again, making four copies of the files.  Also, my resistance

to totally plunge into DLs is that I still play vinyl and CDs,

although I do expect DLs in the future to be the norm.

And I do likenbeing able to buy music, download it and 

be able to play it on my system a few minutes later.

California Jim

Hi aleg,

Just to clarify that I was not suggesting that backups are optional,it was, in fact, the  backup copy I used to recover my data. I was just explaining the difference between Raid 1 and a backup. As I said above, I am will make a second backup and store at another location. I am doing this as I have just checked my Hiscox insurance policy which covers the full value of my CD's but only up to £500 for digital files. I guess this is understandable as it may be difficult to prove the extent of any loss of digital files.

Gerry

Gerry

All of the above just reinforces my view that RAID in a domestic environment is a waste of money and effort.

All that is required is a NAS with a direct backup (for immediate recoveries) and a further backup held off site.

That thought has crossed my mind also. the advantage of the Raid1 is that you continue to access your music in the event of a hard drive failure; retrieving the files from a back-up source can take some time. Also you will always have an up to date back-up copy.

Gerry