[VLM]

My favorite raid 5 failure mode is when a old hardware card fails and you have no stock spare and the maint contract was not renewed years ago and the cost of a new card is too much to be expensed and buying as a capital replacement will take a week or two minimum to be approved. And/or the card has been discontinued so you have to buy a used one from a shady foreign surplus dealer. I've seen too much of this type of thing... I can tolerate the (minimal) cost of software raid but I can't survive the possible downtime of hardware raid, so its been software raid for me for pretty much the last decade.

Another fun one was the quad redundant power supply with all four plugs going into the same power strip.

And there was the power supply that blew out every drive in the box simultaneously. I suppose its not any worse than a lightning strike, other than the onsite tech assumed it was a cooling failure, so he replaced the dusty fans and all the drives, thus destroying an entire set of drives upon powerup (and fans, I would guess).

The poison drive tray where every slot you jammed it into, it bent the backplane pins. That turned into a huge expensive disaster.

[akg_67]

You don't need to replace old/discontinued RAID card with the used one (assuming you mean same make and model). The new card from same manufacturer will work. The RAID card writes DCBs on disks that are read by the new RAID card upon replacement.

[CrLf]

"The RAID card writes DCBs on disks that are read by the new RAID card upon replacement."

Which also makes for very nice RAID failures, like this one that has happened to me on an HP controller:

A drive fails because of some SCSI electronics problem and when you replace it, the controller gives it a different SCSI ID. Now, the controller maps RAID arrays to drives, and it is now impossible to add the replacement drive to the degraded array because SCSI IDs in these controllers aren't user defined and the controller doesn't allow the degraded array to be modified.

And since the controller has now happily written it's configuration onto the drives, it doesn't matter that you shuffle the drives around to try to force the controller into giving up it's internal configuration.

Oh, and the controller is an onboard controller, so you can't just replace it with another one (which would also read the configuration on disk and put himself in the same stupid state, I suppose).