ext3 jbod to ext3 raid1 while swapping drives ?

[togusa]

Hi, the catch is that i want to swap both drive while keeping the data.


This is my system:

hd: 2 x 750gB seagate barracuda 7200.11
(yes i rtfm page9 and page28, but hitachi and western digital were unavailable in montgallet, the parisian computing shops district, samsung causes many problems with the 4220, and maxtor is basically a seagate 7200.11 rebranded with only 3y warranty instead of 5)
actual format: single drive in ext3 jbod
wanted format: ext3 raid1
network devices: freebox v5
connection via samba / xp sp2 / firefox

My problem is that i have a lot of data on the jbod drive that i cannot back up anywhere else at the moment. Some are family photos repertories which were messed up thanks to filezilla who did not keep the original date of the photos.

And i may have modified the library of 4220. So i would like to make a clean start with the second drive.

So here is what i would like to do:
1. take out the system ext3 drive with many files already on it which is connected on the p2 sata connector and install the future ext3 system drive (bought today) on p2 and format it alone as system drive.

2. then reinstall the former ext3 system drive as the secondary drive on p1 sata connector, not format it, and transfer all the files onto the new ext3 system drive connected on p2. Except for the photos repertories with correct dates which i still have on my pc.

3. format the new secondary (former system drive) in ext3

4. make raid1 from p2 system drive to p1 secondary drive

Is this possible without any problem arising ?
Any advice much appreciated !

[vishcompany]

s this possible without any problem arising ?

Quick answer: no.

Long anser: Setting up the RAID1-mode will delete all data on both disks! You will have to get a second clean drive and then copy the data from the full drive onto the NAS by installing it into your PC or a USB-case. Later on you could use this third drive as an external backup-drive, something to be recommended anyway.
If I was in your position, i would get a 750 GB USB-drive (make sure it has a SATA hdd inside) swap the hdds and proceed.

[togusa]

Thanks vishcompany

I don't understand: if one drive in a raid1 setup fails, how are we supposed to reinstall another drive in the nas, as anyway all the data one the valid drive will be erased when reformatting and reseting the raid1 ? Not everyone has a spare and empty 750gB ready for use...

So now i cannot do raid1...

By the way i don't think there is anything about this on the 4220 english manual...

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edit: the english manual says :
- page 28 "formatting the hard disk will erase all data on the hard disk. Please save all data on it before proceeding to format it"
- page 30 it describes how to replace a failed hard drive in raid 1.

The manual does not say it will erase all data on both drive, only on "the" hard disk... It is not very clear that you cannot go from jbod to raid1 without losing data. If i had known this i would have proceeded differently...

[togusa]

This is a big problem : if the jbod primary hard drive (where the nas system files are stored) fails, then the 4220 stops working ?

[vishcompany]

I don't understand: if one drive in a raid1 setup fails, how are we supposed to reinstall another drive in the nas, as anyway all the data one the valid drive will be erased when reformatting and reseting the raid1 ?

If one drive fails, you only need to exchange it with a new one and the box will re-establish the RAID array automatically. But this does not mean, that you can simply declare a JBOD-disc a RAID-disc.

What you still could do, is to install your second drive as JBOD, then install the rsync-package and create a cron-job, which automatically synchronizes the data every night at - let's say - three o'clock.
This is almost as accurate as RAID1 and has the advantage, that, if you delete a file by accident, you still can get it back from the second drive before the synchronization. Or you set up rsync in a way, that it does not synchronize, but back up the data, so you won't lose anything.

If you are interested in this solution, search the forum for rsync and google cron. Of course you will have to install the ssh-server (which is a package from Raidsonic. To be recommended). To access the Box, you use putty (google).

[togusa]

Thanks vishcompany for your answers

But I have to ask again: if the jbod primary hard drive (where the nas system files are stored) fails, then the 4220 stops working ?

[vishcompany]

Honestly, i don't know. But even if this is the case, you would not lose the data, if you go for the JBOD / rsync - solution I proposed.