Hi again, I am now trying to write a vector to an HDF5, this time using a DM structure to impose the vector layout. Creating the vector with (as in src/dm/examples/tutorials/ex10.c) DMCreateGlobalVector(da2D,&gauss); every works fine, i.e. the hdf5 file has the correct layout given by the dimension of the DM. On the other side, if I use: VecCreate(PETSC_COMM_WORLD,&gauss); VecSetSizes(gauss,PETSC_DECIDE,Nx*Ny); VecSetDM(gauss,da2D); VecSetFromOptions(gauss); VecSetUp(gauss); the hdf5 file contains a single dimension vector, apparently negecting the VecSetDM instruction (I would need this for vectors created by MatCreateVecs, in order to have both right and left vectors available). I did some testing but I did not manage to solve this. Is there anything I am doing wrong, or is this the way it is supposer to work? Thanks as always for your help, Gianluca