It's quite a long story.
My server has 6 disks 150 GB each but only one controller.
The first operation I did was to mount 3 disks in RAID 5 but the performances were awfull.
That's why SUN recommend me to mount the disks in RAID 0+1 or best in RAID 1+0 with the commands that I posted in my first post. The problem is that RAID 1+0 doesn't work with SVM : the last command metainit d130 1 2 d120 d121 -i 64k fails because it needs physical devices and not logical devices.
Anyway I choosed the solution RAID 0+1 and now it's fine, except that I will need a second controller to improve the performances .
Thanks again