This is bit of a follow on from my previous question us HP Smart array.
Is it possible to RAID a single ssd? What setting will need to give it?
What benefits will I have?
No, you can't raid a single SSD. You need at least 2 drives for the simplest raid level - 1 or 0. There would be no real benefits from running it as a raid, tho a raid card may let you use drives with a SAS interface, or have other useful features even when used with JBOD or single disk layouts.
RAID stands for redundant array of inexpensive/independent disks. This is a clue that a single disk will have no benefit whatsoever.
However, should you decide to get a second disk an have a RAID set up, I wouldn't use a software RAID solution anyway.
Is it possible to RAID a single SSD?
It is not possible to assemble an array of multiple disks with a single disk.
You can connect a single disk to a RAID controller and use the JBOD setting. That will treat it as a single disk. So you can use a single drive. It just will not be part of a RAID array.*1
What setting will need to give it?
mdadm --create /dev/md0 --level=mirror --raid-devices=2 /dev/sdb1 missing
What benefits will I have?
With a single disk: No benefits.
As others already posted: Many servers have an internal SD card reader. It is not uncommon to install the hypervisor on that and keep a spare card with a backup.
*1: Nitpick, in theory you could use mdadm to create an array from multiple partitions. That would result in all the bad parts and none of the benefits of RAID, so no sane person does that.