Swapping 2x2TB ZFS disks with disks that are (a little) lesser in size.

[janisve]

I have a situation where I have phisically attached 2x4TB disks, however the not-so-new DELL PowerEdge 2850 addresses only 2TB

So I thought I would replace those 2 x 4TB with 2 x 2TB and use those extra TB's on a modern machine. However, the real 2TB disks are lesser in size:

(output by geom disk list)
One of 4TB disks:

Code:

Geom name: da3
Providers:
1. Name: da3
  Mediasize: 2199023255040 (2T)
  Sectorsize: 512
  Mode: r2w2e5
  descr: ATA Hitachi HDS72404
  lunid: 5000cca22bc21498
  ident: PK1311PAG4KW6S
  fwsectors: 63
  fwheads: 255

Real 2TB disk:

Code:

 Geom name: da2
Providers:
1. Name: da2
  Mediasize: 2000398934016 (1.8T)
  Sectorsize: 512
  Stripesize: 4096
  Stripeoffset: 0
  Mode: r0w0e0
  descr: ATA ST2000DM001-9YN1
  lunid: 5000c5003ce7842f
  ident: W1E3AEMW
  fwsectors: 63
  fwheads: 255

Currently less that 1,1TB is being used.
From trying and searching, I found out that ZFS doesn't provide replacing disks with lesser size.

Now what are my options? Can i just dd first 2000398934016 bytes to new disk? (I'm afraid there is some info stored on last bytes of drive?) Or is there a way to copy ZFS layout (I have a few volumes set up) and just copy/paste those files to new disks preserving permissions, links, etc.?

Thanks for any help.

 

[cyberjock]

The only way I know of to do what you want is to make a new pool with the 2TB drives, copy the data over to the new pool, then remove the old pool. Update your shares as necessary and things should be back to normal.