I have a beginner question about using software raid on Ubuntu and what the smartest way is to build the hardware for a home-file-server.

My plan is to have a server with one system disk(SSD 60GB) and 3-6 2TB disks in a software raid 5 or 6 or 10(haven’t decided yet...) using mdadm. So my idea is to not include the SSD drive in any raid, and just run it standalone with Ubuntu server.

Anyhow, let’s say that I create a raid5 with four disks. After a awhile the SSD crash(as I probably will do after a couple of years). What will then happen with my raid 5?

Will I be able to buy a new “system disk” and just install a fresh Ubuntu version + mdadm and then the system just recognize my old raid5 that was built on the old crashed Ubuntu? Or should I start to cry because my raid5 is gone? Maybe there are some checksum or similar(I don’t know software raid 5 works…) that are needed from the old crashed Ubuntu to recognize the raid5?

The reason to why I want to have separate system disk is because I want a fast disk for the system and separate the file storage on separate disks that are bigger(and slower) but cheaper ). Also, if not really really necessary I want to avoid using two SSD in a raid as system disk(disk are expensive).

I want to keep my system as simple as possible so I want to avoid the need to take system backup(like snapshots). The server is only for home use so I doesn’t matter if I have a downtime of a couple days, and installing Ubuntu again from the beginning is simple and not so time consuming. The most important is that I can connected the raid5 to the new freshly installed Ubuntu.

Many thanks in advance for your help!