Expansion driver in parallel with medium-sized meshes

[FRUrgorri]

I was launching the expansion driver with insulating walls and very small fields (Ha = 50) and I found the following issue:

With a mesh of ~68k cells and using 20 processes, the integration has not started after 15 hours:

`================================================================
aac101
Using: 20 procs in 2 nodes

Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : 111 entities
Info : 111 entities
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : 111 entities
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : 111 entities
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : 111 entities
Info : 111 entities
Info : 111 entities
Info : 111 entities
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : 111 entities
Info : 61761 nodes
Info : 61761 nodes
Info : 111 entities
Info : 111 entities
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : 61761 nodes
Info : 61761 nodes
Info : 61761 nodes
Info : 61761 nodes
Info : 61761 nodes
Info : 111 entities
Info : 61761 nodes
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : 61761 nodes
Info : 111 entities
Info : 111 entities
Info : 111 entities
Info : 61761 nodes
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : 61761 nodes
Info : 111 entities
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : 111 entities
Info : 61761 nodes
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : 111 entities
Info : 61761 nodes
Info : 61761 nodes
Info : 111 entities
Info : Reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'...
Info : 111 entities
Info : 61761 nodes
Info : 61761 nodes
Info : 61761 nodes
Info : 61761 nodes
Info : 61761 nodes
Info : 61761 nodes
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : 67974 elements
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
Info : Done reading '/ws/blankets/GridapMHD_master/GridapMHD.jl/meshes/Expansion_68k.msh'
[1.450e+01 s in MAIN] triangulation
[5.483e-01 s in MAIN] pre_process`

I cannot solve this problem in serial because more memory is needed than the avaliable in one of the cluster nodes (191 Gb)