ok and thanks for the reply, so if I understand it, restart your bitcoin wallet does not create any problem (apart from losing a share if it happens at the time of the reboot)
Correct, you'll just chance losing a share if it were to happen during your restart. Otherwise no worries. I have done it multiple times where I just restart bitcoind without touching P2Pool and it recovers nicely.
is an experimental configuration to see if it works, surely if all goes well I will invest some money in a faster computer.
The HD is 7200rpm, but I'm going to replace it with a ssd
Using openSUSE linux, cpu utilization varies between 20% and 70%, I have 4 gb of ram in total and by now they are only used 2.6
Ok, that sounds fine. I'm thinking the disk will really help with the GBT. 1s is not good, but it's workable for now especially if you're just testing it and have plans for something beefier later. I would just caution you that if you are running the wallet on the same "server" you take plenty of backups... with only a single drive if it goes you'll lose everything if you don't have backups.
And, I would also suggest that if you are planning on opening your node to be public (and possible even if not), if you have the resources, run your wallet on a totally different machine. This way if something bad were to happen (hack) your wallet won't be compromised.