Hi guys, only have a 4.7 unRAID here and would like to format a new 4TB Seagate DM disk with reiserFS on it, copy data onto that disk and then move that disk to another unRAID 5.0.4 machine *without* reformatting it (keeping the data). Would that work and is the reiserFS filesystem the same on both unRAID versions?

 

I would of course rebuild the 5.0.4 array from scratch and re-calculate the parity there... Thanks for confirming.

 

That's not possible.  You can't add an already populated disk to an existing array, at least with unRAID.  When you attempt to add it to the 5.0.4 array, unRAID will zero the drive and then format it.

 

EDIT:  To clarify you can't add an already populated disk to any array in unRAID (new or existing) and keep the data already on the drive.  It will be zeroed and formatted.

 

EDIT: Striking out incorrect information.

That's not possible.  You can't add an already populated disk to an existing array, at least with unRAID.  When you attempt to add it to the 5.0.4 array, unRAID will zero the drive and then format it.

Is that true?    I thought that if the disk had already been used by unRAID so it had the unRAID signatures then the data was kept when being added to a new array?

 

I guess the thing to do is carry out a test to find out?

 

regarding the other point raised by OP, the reiserFS format used is identical in 5.7 and 5.04.

That's not possible.  You can't add an already populated disk to an existing array, at least with unRAID.  When you attempt to add it to the 5.0.4 array, unRAID will zero the drive and then format it.

Is that true?    I thought that if the disk had already been used by unRAID so it had the unRAID signatures then the data was kept when being added to a new array?

 

Exactly! I am not talking about _adding_ a disk to an array, but DELETE the array, re-map it from scratch and start it. All unRAID formatted drives are seen as is (they would not get formatted and data is kept), only parity is set as invalid and parity re-calc is started. This I have done numerous times. The question was IS there compatibility in terms of reiserFS between unRAID 4.7 and 5.0.4 as the linux version used is different.

 

regarding the other point raised by OP, the reiserFS format used is identical in 5.7 and 5.04.

 

If this is so, I will give it a try.

I have tried this *within* an array (same unRAID version) numerous times and it works very well.

And actually, reisereFS must be identical as there is no data migration or filesystem upgrade performed when upgrading from unRAID 4.7 to 5.x, right?

 

 

I use this technique for consolidation and upgrade of several smaller data disks at once:

- stop array

- add new disk(s) to array (say 4TB)

- delete array config

- remap drives into array including new disk(s) but without parity drive

- start array (new disk(s) get formatted; existing data disks are untouched)

- copy data from say 4x 1TB existing disks to new 4TB drive

- stop array

- remove 4x 1TB old disks

- delete array config

- remap drives into array again (including parity disk at that point)

- start array (no data disks get formatted at this point)

 

Parity re-calc is kicked in, data is immediately available.

Works like a charm...

Hi guys, only have a 4.7 unRAID here and would like to format a new 4TB

4.7 does not support drives larger than 2.2TB.

Hi guys, only have a 4.7 unRAID here and would like to format a new 4TB

4.7 does not support drives larger than 2.2TB.

 

That is a good point! I knew I might forget something - thanks!

 

Edit:

But 4.7 is pre-clearing 4TB drives just fine!?

My mistake.  I forgot that you could run "new config" and effectively add a previously used (by unRaid) drive to an array.  I will correct my original post.

No prob, thanks 

A couple of "nits" ...

 

=>  First, you don't have to do a "New Config" to add a drive with existing data on it to an UnRAID array UNLESS the array has a parity drive.  Granted that most do ... but it's not unusual when folks are initially populating an array to not include a parity drive until they're done.

 

=>  Second, while v4.7 doesn't support 4TB drives, if you're running "outside" of UnRAID on hardware that supports > 2TB drives, you can indeed (as already noted) pre-clear 4TB drives on that system.    If a system supports that; then I believe (but have not confirmed) that you could mount a 4TB drive outside of the array, and then copy data from an array drive to that drive (and then, as asked, move it to another UnRAID system).

 

Note, however, that independent of whether that works on a specific system; there's not much difference in the time it takes to copy data internally vs. just doing it across the network as long as (a) you have a Gb network; and (b) you're copying it to a v5 system that doesn't yet have a parity drive assigned.

 

 

=>  Second, while v4.7 doesn't support 4TB drives, if you're running "outside" of UnRAID on hardware that supports > 2TB drives, you can indeed (as already noted) pre-clear 4TB drives on that system.    If a system supports that; then I believe (but have not confirmed) that you could mount a 4TB drive outside of the array, and then copy data from an array drive to that drive (and then, as asked, move it to another UnRAID system).

 

Thanks Gary for your comments! I am just confirming that mounting a 4TB drive outside of the array just works as pre-clearing it on a 4.7 system (of course, if the hardware supports drives bigger then 2.2TB).

 

Note, however, that independent of whether that works on a specific system; there's not much difference in the time it takes to copy data internally vs. just doing it across the network as long as (a) you have a Gb network; and (b) you're copying it to a v5 system that doesn't yet have a parity drive assigned.

 

The only reason for that would be to use the hot plug carriers on the server for naked drives instead of putting them in USB cases. Then the server only has USB2 and internally it copies much faster via SATA instead of USB2 over GbE (from another server).