Merging/Appending Disks with ZFS and Data Loss

[oruchreis]

Hi,
I have 2 hardware RAID 10 array, 6TB and 4TB. Can I merge these disks and use them as 10TB with ZFS? Also if I add another 6TB RAID10 Array to the system, can I append this new disk to the ZFS pool and use as 16TB one large disk? Is this secure to keep data like that?
For example, that 4TB raid10 has 4x2TB disks. If I want to change these disks to 3TB and make the array 6TB, then can I update ZFS pool with this new array. I mean before, I have 6TB + 4TB then I pulled out 4TB and after that I added 6TB array. Can I do this with ZFS without any data loss?

NTFS can be expanded without data loss so, in Windows side, I'm planning to expand the partition when I add a new disk to the ZFS pool.

Also which one should I chose stripe or RAID-Z1?

Regards.

 

[xbmcg]

RAIDZ1 is the RAID5 equivalent, stripe is the RAID0 equivalent and mirror is the RAID1...

if you want a raid10, first you need to make 1 zfs mirror named let say my2ndMirror, and then make another mirror with the next 2 disks named AGAIN my2ndMirror. This would add the second mirror to the first volume and create the equivalent to a RAID10 (2 mirrored Disksets, striped).

id you add data to them it would be distributet that way:

first sektor: disk0 + disk1
2nd sektor: disk2 + disk3
3dr sektor: disk0 + disk1
4th sektor: disk2 + disk3
...

 

[oruchreis]

Thanks for reply. But I have already hardware RAID10 with my raid card. I want to merge these two arrays into one big volume. I supposed that I can do this with ZFS pools. But I've searched internet and I figured out yet that ZFS pool can't be modified. I have a windows cluster server that uses freenas with iscsi. And I don't want users to see sharing folders like disk1, disk2, disk3, etc.. I want users to see a big folder that can expanded at server side. I don't know how can I do it. For example, I wonder how file sharing sites like dropbox, rapidshare, hotfile handles this issue. There are a lot of disks, and users sees only one sharing folder. And the system admin can expand the sharing folder by adding disks to the array. I'm using DFS right now but it doesn't fulfill my saying. I supposed that ZFS can do it.

 

[peterh]

of course zfs can use as many discs as you want in a single filesystem.
But you will have to create a fresh pool of discs ( you cannot use your current filesystems) and
you should also take the opportunity to junk your hardware raid.

See the documentation section for details, its well written and it contains links to sun/oracles "best
practice" pages.