We run a HyperV server on RAID-6 (the OS is Windows Server 2008 R2). The hardware is LSI MegaRaid SAS 8704EM2 controller, with 4x 1TB WesternDigital SATA drives. The server is up & running on this hardware for 4 months already.
Every week however, there's a warning message in the MegaRAID storage manager dashboard saying, I quote, "Patrol Read can't be started, as PDs are either not ONLINE, or are in a VD with an active process, or are in an excluded VD". Don't ask me what's PD or VD - I don't know.
I've googled and discovered the following:
- Patrol read (also available on Intel and Dell RAIDs) is useful diagnostic procedure that checks that all data on all drives can be read.
- The official documentation "Appendix A Events and Messages" only lists the possible messages (without any hints on fixing the conditions). It also says "Warning" error levels means "Some component may be close to a failure point".
Should I worry about my data? How do I fix the thing?
Thanks in advance!