Please make a M.2 form-factor SATA interface version of the MB840M2P-B, so that one could boot from the drive and it would fit in a half-height slot. The 2.5inch drive SATA version is almost 5inches tall, so it will never fit in many rackmount servers.
The ToughArmor MB839SP-B is great because the SATA connector is completely onboard, no need for data and power cables. Because it is SATA, it should be a bootable harddrive. Hot-pluggable from the rear of the machine, the hard drive can be removed without opening the case. HotPlugging the SATA drive version is great, but just having physical access by powering down would be good enough.
The problem is 4.8 full height PCI inches is often too tall.
Server bootable harddrives require SATA. Booting from NVMe / PCIe is often not compatible with even servers a couple years old. Dell's BOSS card is SATA and only supported for their fourteenth generation r740. Managed to get it working in a r720, but it was a major pain involving racadm BiosBootSettings.
Repurposing old rackmount servers for storage servers ( FreeNAS / FreeNAS VM on top of XCP-NG ) is even better when there are options to boot from real SolidState harddrives so one can dedicate all the Spinning Platters to bulk storage. Server companies push you into purchasing their $4000.00 solid state drives while FreeNAS runs off zfs raided USB sticks. However running FreeNAS as a virtual machine requires real drives for the HyperVisor. When running Linux as the iSCSi and / or NFS server, SSDs are needed as well. All of these options support software RAID.
Disconnecting wires, un-racking and removing the cover takes too much time.
IcyDock providing SATA in a PCI slot without wires would be so nice.
Even nicer would be two M.2 SATA drives in a single half-height card.
Nicer still would be hardware raided M.2 SATA bootable drives in a single PCIe slot.