2x R920 lost SSD access after power cycle and restart

Good day community,

we support a rather old environment for a client that was archiving 2x R920 for some time now.

We had to power down and start up the systems yesterday and both systems show similar errors.

Both R920 run a 10x 800GB SSD config with 2x SSD RAID10 for system and 8x SSD RAID5 for data VDs.

The first server has lost all 10x SSDs and so far we have not been able to access anything.

The second server has lost 9x SSDs and only shows 1x SSD from the RAID5 config.

We have tested (with the one functional SSD) whether the Slots, RAID Controller or backplane is not working, but we can use the good SSD in als slots of the server (always shows up correctly as RAID5 with only one SSD and the other ones missing) and also the other second server, the SSD shows up in all slots as "foreign" RAID 5 with the rest missing.

Both servers lost nearly all SSDs at the same time?!

Did someone ever experience something similar?

Thanks for your answers.