Is this possible?

 

Basically what i have at the moment is a DAS attached to my HTPC with 4 x 1TB drives spanned.

 

What i thought might be possible is to:

1) shrink the spanned volume, that should free up 1 drive

2) use that drive in the unraid array

3) move 1TB of data to the unraid array

4) repeat steps 1 - 3 till all data is moved over.

5) buy another 1TB drive and add as parity after all data has been moved over

 

Also my current HTPC is the hardware i want to use for my unraid server, while moving the data over i can use a spare pc thats lying about, as the OS is installed on a usb will there be any problems starting off on 1 set of hardware, then moving everything to a different set?

 

*edit* added step 5, forgot in original post

Is this possible?

 

Basically what i have at the moment is a DAS attached to my HTPC with 4 x 1TB drives spanned.

 

What i thought might be possible is to:

1) shrink the spanned volume, that should free up 1 drive

2) use that drive in the unraid array

3) move 1TB of data to the unraid array

4) repeat steps 1 - 3 till all data is moved over.

5) buy another 1TB drive and add as parity after all data has been moved over

 

Also my current HTPC is the hardware i want to use for my unraid server, while moving the data over i can use a spare pc thats lying about, as the OS is installed on a usb will there be any problems starting off on 1 set of hardware, then moving everything to a different set?

 

*edit* added step 5, forgot in original post

There is no problem with switching hardware... the only issue might be the order the disks are identified on the new hardware vs. the old.  You will need to do a screen-shot of the old disk assignments on the "Devices" assignment page, and then once on the new hardware, re-assign the disks to their correct positions in the array.  Most critical will be the parity drive. (you can swap around the other disks without losing data, it will just be on disk2 instead of disk3 if, for example, disk2 and 3 were transposed in their assignment.)

 

I would purchase the parity drive first... Since you are moving the data and will not have any way to recover it if a disk fails, I suggest you put parity protection into place initially.  Yes, your transfers will be slowed... but your data will be safe.  (To me, that is more important.)  The cost is pretty reasonable, as 1TB drives are well under $100.

 

I would download and install the preclear_disk.sh script and use it on the disks before you add them to the unRAID array.  It will identify any marginal disk before you trust your data to it. (I know you had them in the PC, but it does not tell you of the errors... the SMART firmware on the disks will, if you give it the chance)

 

Joe L.

 

 

Thanks for replying Joe, im not 100% sure i will be switching hardware yet, the idea was im currently using a 4850e for my htpc on a 780G motherboard, i was considering getting an Asrock ION 330, installing XBMC on it and using my current HTPC as a server, but on the other hand it means having to buy a whole new HTPC when i have a perfectly capable one already, and it would mean having the old HTPC case lying around (Antec 2480, because going to put the server in a Tt Tai-chi which has 11 5.25 bays) and a motherboard lying around (A SLi motherboard with an FX55 CPU, 2GB of RAM, could use the SLi pci-e slots for additional SATA when i run out onboard.  It is also atx so wont fit in the 2480).

 

So i think for the time being i will just put the SLi motherboard in the Tai-Chi, add some 4 in 3 caddies (would use 5 in 3, but already have a 4 in 3 and want it to match, plus 12 HD's will keep me going for a while (case has 11 slots, alowing 3 caddies, plus a spare drive for dvd and one for power button... which reminds me.. think i lost the power module).

 

The only reason i was going to leave the parity drive till last was because i figured it was going to take long enough as it was, what with having to shrink the volume, move the drive across, preclear it, add to unraid, move 1tb of data across, shrink, move drive, preclear, add to unraid, move data, shrink, move drive, preclear, add to unraid, move data, move last drive, preclear, add to unraid.

 

How long does it take to preclear a drive?

Thanks for replying Joe, im not 100% sure i will be switching hardware yet, the idea was im currently using a 4850e for my htpc on a 780G motherboard, i was considering getting an Asrock ION 330, installing XBMC on it and using my current HTPC as a server, but on the other hand it means having to buy a whole new HTPC when i have a perfectly capable one already, and it would mean having the old HTPC case lying around (Antec 2480, because going to put the server in a Tt Tai-chi which has 11 5.25 bays) and a motherboard lying around (A SLi motherboard with an FX55 CPU, 2GB of RAM, could use the SLi pci-e slots for additional SATA when i run out onboard.  It is also atx so wont fit in the 2480).

 

So i think for the time being i will just put the SLi motherboard in the Tai-Chi, add some 4 in 3 caddies (would use 5 in 3, but already have a 4 in 3 and want it to match, plus 12 HD's will keep me going for a while (case has 11 slots, alowing 3 caddies, plus a spare drive for dvd and one for power button... which reminds me.. think i lost the power module).

 

The only reason i was going to leave the parity drive till last was because i figured it was going to take long enough as it was, what with having to shrink the volume, move the drive across, preclear it, add to unraid, move 1tb of data across, shrink, move drive, preclear, add to unraid, move data, shrink, move drive, preclear, add to unraid, move data, move last drive, preclear, add to unraid.

 

How long does it take to preclear a drive?

When you add a drive to an existing array, if a parity drive has been assigned, and the disk being added has not been pre-cleared, the first thing that unRAID will do is clear it.  For a 1TB drive, this can take between 2 and 4 hours (depending on hardware speeds)  During this time, the unRAID array is not available to do anything else.  It is effectively off-line.  Once the drive clearing step is completed, the array is brought back on line and you are presented with a "Format" button that will format and un-formatted drives.  That process takes place while the array is up and on-line, and only take a minute or two.  Once formatted, a drive can have data copied to it.

 

If you pre-clear a drive, you can eliminate the 2-to-4 hours of array down-time.  When adding a drive unRAID will recognize the pre-cleared drive by a special signature written to the drive.  It will then skip the clearing step since it knows it is all zeros and parity protection will be maintained when it adds it to the array.

 

If you do not assign a parity drive until after all the data is migrated, as you have indicated, there is no need to pre-clear any drive to force it to have all zeros.  You will be able to proceed as you initially described. unRAID will not do any pre-clearing of it own unless a parity disk is in place and parity protection established.

 

The preclear script does a full read of all the blocks on the disk, then clears all by writing zeros, then post-reads all the blocks.  It allows the SMART firmware on the disks to identify and re-allocate any bad sectors.  For that reason, it takes about 3 times the time it would to just write zeros to the drive.  A 1.5TB drive seems to take about 12 to 16 hours for a single cycle.

 

If you are in a hurry, the pre-clear can be occurring while you are transferring data from your existing PC.  It is done completely outside of the protected array.  If you are in a real hurry, you can use the "-n" option to clear only, and not perform the pre/post read that allows SMART to re-allocate any bad sectors.

 

Other than that, you'll be spending a lot of time shrinking the windows array.  I have a feeling that is not a quick process, but I've no experience at all, never having used that feature of windows.

 

Joe L.

So whats your suggestion?

1) Buy 1TB drive and use as parity drive

2) Shrink the volume to get a drive

3) move drive to unraid server and run pre clear

4) approx 10hrs later (more likely look at it the next day) add pre-cleared drive to unraid array then start to move data across

5) repeat steps 2 - 4

 

I'm not in any particular rush, just want to do it right this time, wasnt a good idea doing a spanned volume, because if 1 drive fails i could potentially lose the lot.

So whats your suggestion?

1) Buy 1TB drive and use as parity drive

Sounds good...

2) Shrink the volume to get a drive

This will take some effort from what I've read.  I looked at the help on my Vista PC and see no way to remove a drive from a spanned volume.  Or rather, no way defined by Microsoft. 

 

One person figured out a way... but it seems to come with some risks.  You must have enough free space on the drives, and you must not have any un-moveable files. From the description, there is no way to specify which drive to remove... the author resorted to unplugging drives, each in turn to figure it out.

See this post: http://www.richardbenson.co.uk/2008/10/removing-a-drive-from-a-spanne.html

and here: http://www.tomshardware.com/forum/198895-46-removing-disk-spanned-volume

and here: http://www.tech-archive.net/Archive/Windows/microsoft.public.windows.file_system/2008-02/msg00065.html

3) move drive to unraid server and run pre clear

Sounds good.

4) approx 10hrs later (more likely look at it the next day) add pre-cleared drive to unraid array then start to move data across

In the interim, if it is possible to continue to copy from the PC and also shrink the volume on the PC, you could start the next shrink-operation at the same time.  (Again, no idea if this is possible... if spanned volume is accessible while being shrunk)

5) repeat steps 2 - 4

 

I'm not in any particular rush, just want to do it right this time, wasnt a good idea doing a spanned volume, because if 1 drive fails i could potentially lose the lot.

It will take a bunch of time.  Only way I can think to speed it up at all is to initially get a pair of 1TB or 1.5TB drives for the unRAID server, that way you can move a lot of your files in a single copy operation without having to physically move disks from the other PC.  Then, delete the files, shrink as much as possible in a single "shrink" and rinse-lather-repeate.

 

Joe L.   

I'm hoping it wont be too bad because the spanned volume is only used for media storage, i have a seperate HD for the OS etc, there are currently 4 x 1TB drives, but im only using just over half of it (last i checked) so one of the drives should be available to take out the array straight away with a shrink.  It depends how much the sofas cost how much will be in the budget for the server, there was originally £2700 budget for everything,

£1130 has gone to an Onkyo TX-SR577 amp, Wharfedale 10.5 floorstanders, Wharfedale 10.1 bookshelf speakers, Wharefdale 10CM centre speaker

£300 for a BK XLS200 Subwoofer

£50 for 26mtrs Van Damme blue speaker cable

£60 for bookshelf speaker stands

£40 for a Lindy mains filter

£200 is budgeted towards a holiday in Nov

 

Total so far £1780

 

which leaves about £1000 for a 3 seater sofa + 2 seater sofa + server parts + leveling and laminate floor.

 

So i think the money for the holiday is going to go, lol.

So i think the money for the holiday is going to go, lol.

Oh no........

 

Oh well... sounds like you can stay home and watch some movies...

lol, its ok, i'll just save up the money over the next 3 months for the holiday instead.  I might just try shrinking the drive when i get home, see if i can take one of the drives out of the array.  If that works, i'll order a sata caddy, usb pendrive, and a 1TB drive, once that arrives i can order an unraid pro reg key and get started.