500MB is just not enough RAM for a good HA experience. I would go with at least 2GB. If you have a few add-ons running I would go with 4 or more.
If it's an option I would always go with an SSD for HA. It makes a big difference in usability. Writing often and a lot to SD cards, like HA does, kills them way too fast
If it's an option I would always go with an SSD for HA. It makes a big difference in usability. Writing often and a lot to SD cards, like HA does, kills them way too fast