1. It means to "review" the contents of the log, so you are aware of any hardware issues (or at least the contents), then "clear" it because it is full. 2. No number of reboots or power cycles will bring disk 4 online. You need to rebuild the missing disk in the RAID array. You could determine if it failed because it is faulty or because of some other reason. If faulty, replace the disk. If for some other reason, then that needs to be addressed - usually via firmware updates. Make sure you have a good backup. Right now.
1) what does "Review & Clear SEL" mean? 2) this server indicated "degraded" array during POST, after a transient power event, and #4 of 4 HDDs is giving an error indication.  Is a graceful power cycle advisable, in hopes that  #4 comes back online?  Or should I order a replacement?  thanks 
front panel LCD indicates: E1810 HD 3 Fault Review & Clear SEL