HOW-TO make an external disk usable for PC and NAS

[mumsoft]

Hi,

For my final instructions look below for the message "HOW-TO make an external disk usable for PC and NAS - revisited"

I posted my experience in http://wl500g.info/showpost.php?p=48361&postcount=5
You can read there how I got an external usb-disk working for both the WL-700Ge AND my pc. Maybe this information needs some refinement, so I'm wondering what others can say about it.
What I did not tell is that I first had formatted the disk with a primairy FAT partition. That gave it a valid partion table. After that I let the WL-700gE do it's tricks with it, to make it a volume and to define a share on it. But I did this weeks ago and I'm not very sure about the details.
Now I have the pleasure to be able to use the disk wherever I plug it in.
Maybe you need a Knoppix DVD or a Linux RescueCD to do this trick if you use Windows.

Any comment is welcome.

Marc

[saprize]

Hi,
Is your external usb drvie a mirror to the internal drive? I'm using the usb to mirror the internal drive. But, I have no idea how to recover the data from the usb drive. I read your post but didn't really understand. I have a Linux machine but cannot mount the usb drive formatted by the WL700.

[mumsoft]

Hi,
Is your external usb drvie a mirror to the internal drive? I'm using the usb to mirror the internal drive. But, I have no idea how to recover the data from the usb drive. I read your post but didn't really understand. I have a Linux machine but cannot mount the usb drive formatted by the WL700.

My external drive is no mirror, but it could have been.
But to prepare an external disk as I did for use at both a PC and this white NAS, you will have to start with an empty disk, or don't mind that you will lose everything on it.
I will try to repeat my recipe with another disk, and exactly describe what the steps are, because my first successful attempt has been spread out over several weeks.

If your drive acts as a mirror and has been formatted by the WL-700gE itself, you won't be able to mount it on your pc. But, as I have described previously elsewhere http://wl700g.info/showthread.php?t=7663 , you can replace it with the internal drive if that fails, and move on.

But, if you want it to behave as a mirror AND be able to use/see it at your pc, you have to follow my feeble steps, which I will repeat in the near future.
Then you will have to let the NAS rebuild your newly formatted mirror, and that takes several hours. Be prepared. Of course, I you don't mind you could try it yourself now.

Marc

[saprize]

I would prefer the ability to see the contents of the external drive in windows and/or linux. That would be more of a comfort that I wont lose my data. I don't mind erasing the mirror drive and starting over if it gives me this ability. Since I don't trust the mirror I'm still using other backup methods.

Thanks for your help. I will await the exact steps and give it a try.

[mumsoft]

I would prefer the ability to see the contents of the external drive in windows and/or linux. That would be more of a comfort that I wont lose my data. I don't mind erasing the mirror drive and starting over if it gives me this ability. Since I don't trust the mirror I'm still using other backup methods.

Thanks for your help. I will await the exact steps and give it a try.

I have repeated the steps successfully. But I did not succeed when I started with a NAS- used disk. So, be aware that you will LOOSE EVERYTHING on the disk you prepare this way. Furthermore, you need Linux, for instance a bootable Knoppix cd.

1 - prepare the disk at your pc. Make sure it gets 4 primairy partitions, FAT-formatted. These don't have to span the whole disk, and maybe not all 4 are needed, but with 4 it works. You can do this with Windows or Linux or what you have.

2 - attach the disk at the WL-700gE. It will be seen as a Foreign Disk in disk management. Now, erase the disk, and format it, and give it a usefull name, say 'testdisk'. Now, remove the disk with the button: "Savely Remove Disk"

3 - attach the disk at your Linux pc. Open a shell and use fdisk as root. If the disk is called /dev/sda, as in my case type this:
fdisk /dev/sda
It is important that you don't see a message about a missing msdos signature, but if you performed step 1 the right way, it should not pop up.
You will notice that there are no partitions. The 4 partitions of step 1 are gone. Type p to verify this.
Create a new partition (n) that is primairy (p) and is the first (1). Use the whole disk for this, which is default.
You will see something like:
Device Boot Start End Blocks Id System
/dev/sda1 1 9963 80027766 83 Linux
Now change the type (t) in (fd): Linux raid auto-detection
Finally, write (w) this to the disk.

4 - attach the disk to the WL700gE. It will be seen as the "testdisk", but still unallocated. Now create a volume on it, say "testvolume", and create a share, say "testshare". Put some stuff from your pc on this share. Again, remove the disk with the button: "Savely Remove Disk".

5 - attach the disk at your Linux pc. Open a shell with root access, and mount the disk with:
mount /dev/sda1 -t reiserfs /mnt/test
in which /dev/sda1 is the name of the disk-partition and /mnt/test is a directory.
It will take some heavy seconds... and yes... type
ls -all /mnt/test (sometimes dir /mnt/test is the same)
and you will see all that you put on it in step 4.

Last remarks
- I did not try it, but making the disk a mirror should pose no problem, but takes several hours.
- I tried, oh yes, again and again, to use this procedure on a used disk without step 1, because it would be so nice if you could prepare your external disk without losing the data. But that seems impossible. I will ask some advice though, so maybe I come with some sort of a solution in the future.
- I have screenshots for every step, but I have to combine them for this forum. I did not want to wait any longer, so here are the steps in plain English.

Marc

[saprize]

Thanks Marc (Mumsoft).

I can see the contents of the mirror on my Linux machine. I followed all of the steps but on step 4 I created a mirror in the WL700ge. In step 5, I needed to mount from /dev/sdb1.

Not sure why it works or why step 1 is needed. I cannot see the drive in Windows, but that's okay. At least if the internal drive fails I can connect the usb drive to the Linux machine and recover the data on the mirror.

Now I can sleep at night.

[robink]

See here: http://wl500g.info/showthread.php?t=14128

With the information in that thread you can mount the external disk with Linux, access your data, umount and put it back to the WL700gE without loosing your data. No writing on the disk is needed (except maybe on the file system itself), therefore minimising the risks of loosing something..

If we can make a solution that combines the tricks to get a PC/WL700gE mountable disk from an existing WL700gE External disk without loosing data... maybe... If something else comes to mind I will post it here... But don't count on it, my major concern is getting my external disk from my WL700gE to my Linux system (back is not important)...

Greetings,
Robin