Guys, couple of question regarding preclear.sh: where I can I find it and what system would I need in order to pre-format a drive, populate with data and make ready for unRAID? Is it any Linux with ReiserFS or do I need something special... Thanks for the great support!

Check the UnRAID Add Ons, Preclear Disk section.

 

Joe would know best, but I believe it is just a bash script, that should run fine on almost any Linux system (might be permissions issues, need sudo, etc).

Check the UnRAID Add Ons, Preclear Disk section.

 

Joe would know best, but I believe it is just a bash script, that should run fine on almost any Linux system (might be permissions issues, need sudo, etc).

It will almost certainly need to be run as root.

 

The portions of it attempting to verify the disk is not already part of the unRAID array will not be able to open the config/disk.conf file so it will not find the disk is part of your working disks on an alternate server.  Do be careful to not specify a the "wrong" disk.  Trust me, after being completely filled with zeros any data recovery will be impossible unless you are the NSA, and even then, from what I've read, nearly impossible.

 

Joe L.

As a matter of interest, are there any Windows utilities that can preclear drives for unRAID?

I'd be also interested to know if there are Mac OS utilities that do the same thing.

Why would anyone want to run this outside the unRAID box?  It is a simple matter of adding the disk to the unRAID box but not adding it to the array; preclearing the disk; then adding it to the array.

Why would anyone want to run this outside the unRAID box?  It is a simple matter of adding the disk to the unRAID box but not adding it to the array; preclearing the disk; then adding it to the array.

 

Thanks for the insight; I know how to use the script thanks to Joe L. I'm not sure that I should explain why I would want to do this to you, but perhaps other people have different wants/needs/circumstances than you? In my situation, I don't have many slots available on my server, but using USB docks I can preclear drives on my PC and add them all to the server once I get my second eSATA expansion case - arriving soon.

 

 

I am still waiting for hardware to appear for my unRAID build so I though I start ransferring some data to ReiserFS formatted disks, preclearing them first, later simply insert into the array and calculating parity. I though about installing unRAID in a Parallels VM on Mac OS X. Will try this right away.

 

Btw, which ReiserFS exactly do unRAID use?

There is no ReiserFS for Windows. What you can do on Windows is just stress test new drives, like running full DoD erase from programs like Acronis or the like for a couple of days :-)

I was just able to boot unRAID with Parallels (v4.0 build 3848) under Mac OS X (latest 10.5.8 Leopard) and got a login prompt. There were no errors or warnings messages during boot. Now, I would connect a disk via USB, virtually pass this drive to unRAID in the VM and preclear it from there. What is the order, should I format it somehow, or does preclear take care of all of this? Can I start moving data onto this disk to be used later in my unRAID server? Thanks!

I was just able to boot unRAID with Parallels under Mac OS X and got the login prompt. There were no error or warning messages whatsover. Now I would connect a disk via USB, virtually pass this drive to unRAID in the VM and preclear it from there. What is the order, should I format it somehow, or does preclear take care of all of this? Can I start moving data onto this disk to be used later in my unRAID server? Thanks!

 

You should be able to preclear the disk (though i am not sure on the steps exactly) but you will have to format it yourself.  The preclear scripts sets everything up but unraid does the format.  JoeL or one of the more knowledgable linux guys can probably give you instructions on how to do that, and then you will have to figure out if OS X can see the ReiserFS and copy to it.

So, the steps are: preclear, format and copy data? I am running unRAID in an VM now. Attaching a blank disk and have the VM/unRAID see it. I will preclear, then format then nfs mount the data within VM/unRAID and copy within unRAID. There is no direct driver for reiserFS for Mac OS X available.

The kernel sees the new disk (attached to USB) and recognizes it, but preclear is unable to access it. I have attached a snapshot below. Any ideas?

 

Tried booting unRAID on another computer, disk to be precleared connected again via USB. It is seen by the kernel, but as soon as I start preclear it writes:

 

/dev/sdb: No medium found

 

sfdisk: cannot open /dev/sdb for reading

Sorry: Device /dev/sdb is busy: 0

 

The drive you preclear cannot be part of the unRAID array, but must be part of the physical server. Is the sda drive assigned to the array at all?

There is no array yet, just one disk to be precleared hanging on to USB. I have booted from the unRAID USB stick.

try typing

ls -l /dev/disk/by-id

after you plug in the usb drive. 

 

Let's see what it shows there for your disk (the device will be at the end of the line).  It might be your usb adapter does not support the sfdisk commands needed to interrogate the disk, but I really don't know... I've never cleared a disk connected via usb.

 

It says that the disk device is busy... did you mount it? or are you using it otherwise?

 

Joe L.

Not using it otherwise, it is a new disk without a filesystem on it, not mounted. I am checking the ls -l...

I thougt I format the disk (HFS+ from Mac OS X) and tried again, attached the output of ls -l /dev/disk/by.-id. Tried preclear again and it is running (see 2nd attachment). Great, will try more and report. Any things to consider?

The preclear will not be running until you answer "Yes" to the prompt...  Assuming you did, it is running.

 

As for the first screen print, the correct command is

ls -l /dev/disk/by-id

not

ls /l /dev/disk/by-id

 

That is why it had the error message you saw.

 

The "/" character is used in ms-dos for arguments.  In linux, most commands use the "-" character to signify command line options.

 

Joe L.

Is there a command to put a GNU partition table on the disk? Within Mac OS X, I can change between either GUID or MBR but no GNU parted is possible... while probably MBR would be fine?

 

ls /l /dev/disk/by-id

 

That is why it had the error message you saw.

The "/" character is used in ms-dos for arguments. In linux, most commands use the "-" character to signify command line options..

 

Yes, I am forced to the QWERTY layout within unRAID and my keyboard is QWERTZ so I mistyped, I know. Thanks!

Is there a command to put a GNU partition table on the disk? Within Mac OS X, I can change between either GUID or MBR but no GNU parted is possible... while probably MBR would be fine?

 

The preclear disk script writes the entire partition table on its own.  It will put the correct data in the MBR and in the partition table.  When it is done the disk will have a single partition, exactly as needed and recognized by the unRAID web-management screen.  Any other change to the partitioning will make it appear to be a non pre-cleared disk and if assigned to an array with parity established it will be cleared and formatted by unRAID... and it will do it while the array is off-line. (effectively, you will have locked yourself out of your array for 4 or more hours)

 

The preclear allows you to be off-line for only a few minutes... (A HUGE improvement once your family starts to view movies and listen to music served by it)

 

So... don't worry about partitioning, or the MBR, or formatting... anything you do to those first 512 bytes on the disk will make the drive look to not be pre-cleared.

 

Joe L.

So... don't worry about partitioning, or the MBR, or formatting... anything you do to those first 512 bytes on the disk will make the drive look to not be pre-cleared.

 

I didn't mean to alter the first 512 bytes *after* preclearing. I was concerned in setting them properly *prior* running preclear, as I saw a complaining message that the GPT (GUID) partition table found on this disk (from the Mac) is not supported and that I should use a GNU one instead. So I though, it is a good idea first to change the partition table type and then start preclearing. If you say that the preclearing script changes the partition table type anyway (not only removing existing and adding new partition within it!?), then I am probably safe just running preclear, however, when I first run preclear it complained about that GPT (GUID) type partition table scheme.

Changed the partition table type (not partitions) to be MBR and run preclear again... it looks happy now, no complains anymore like in the first snapshot. See attached pic.

You still did not respond with a "Yes" at that last prompt... The pre-clear process will not start until you type "Yes" (Capital "Y", lower case "es" )

 

Glad everything else is set for your pre-clear to continue.

 

Joe L.