Drive accidentally removed from RAID, resolve the PD Missing error without data loss using LSI WebBIOS
Sorry, this isn't the catchiest title ever. But if you encounter the same issue I did recently with my vZilla server's LSI 9265-8i RAID5 array, you likely care more about finding a fix than you do about finesse. The simple steps are featured in the 5 minute video that I just produced, step-by-step.
There's nothing like tense times of potential data loss that tend to get folks jumpy. So I should also remind you, follow this article's advice at your own risk! You may want to instead seriously consider contacting LSI Support instead, if the array contains data that you really care about, especially if you don't have backups. Just sayin'.
The most likely scenario that got you in this pickle is a simple accidental cable detachment from a drive. Or maybe you intentionally wanted to test recovery from a simulated drive failure via a not-exactly-the-same-thing drive removal.
After plugging that cable back in to an existing drive, or replacing the drive entirely, recovery isn't automatic. This particular solution might apply to any 92xx series LSI RAID adapter at RAID5, and may even apply to OEM variants (Dell, HP, IBM, etc.). My 9265-8i was at firmware level 23.11.0-0021.
Here's the excellent article:
Monitoring Direct Attached Storage Under ESXi by Joel Knight on Mar 31 2011.