General computer system

There are various more points related to the general computer system:

• Web plus ftp server:

  We had some unexpected failures with the new web server (which was a refurbished one), and new hardware was purchased and the server was put back to work.

• Back-up system:

  After searching for appropriate storage hardware to run the system, we have chosen some networked storage facility that will cover not only the backup requirements, but for our current and future storage needs (at least for the next few years).

  Where it makes sense (as defined by our backup policy), the backups are done in an incremental fashion, allowing for access to days or weeks of previous data. We are looking at some possible additions that might be desirable.

• Virtualizing services:

  Some of our internal services, previously run by separate, old, less powerful computers (centralized software and licencing servers), have been substituted upon hardware failure.

  The obvious way to replace them would have been just a newer, more powerful computer that integrated all the services, as none of them are really demanding. However, some of the services are tied to a certain configuration (machine name, Ethernet MAC, etc), so we needed to have them, at least, ``logically'' separated.

  Instead of buying new machines to substitute each one, we have chosen the ``virtualization'' way, where a computer serves as a host for several other ``virtual'' computers that run within it, allowing us to cleanly isolate services in different environments, emulating the existence of hardware when needed and, in some cases, just copying the contents of the old computers to the virtual ones without having to reconfigure anything.

  Also, this allows as to add new ``machines'' whenever we want to provide new isolated services within the CPU and memory constraints of the host machine (e.g., the above mentioned backup system is managed by one of those virtual computers).

• Observational course data:

  The usual policy for NOT is that we offer the obtained data to the visitor the next day (on DVD media). Of course, there are times when it would be desirable to access the data during the same night it is being obtained, and the observational courses that are held at NOT are maybe the most relevant example.

  After some problems derived from the visitors accessing the data in an improper way, it has been decided to offer the images in the same way service mode observations are offered: through a read-only copy sitting on our FTP server.

  The mechanisms to do that without having to complicate the procedures for the observers and the staff have been developed and implemented.