Rebuild times vary greatly as there are so many veriables involved. By default perc 4 cards set the rebuild rate to 30% leaving 70% of the processing to the system meaning users are not greatly impacted by slow disk performance. So the rebuild happens slowly in the background, also the raid card has to process new and changed data to the array which also slows things down. You don't mention the size of the disk being rebuilt, obviously larger disks take longer. You can increase the percentage processing time for the perc in either the raid card bios or in omsa if installed. but this will impact performance for the users. This option is in the contoller properties tab. Best is just to leave it rebuilding until it completes.
Hi!...this is in regard to a Dell PowerEdge 830, P4, [NAME] ram, with a Perc 4e/DC UtlraScsi 320 controller, Raid 5, 4-swappable internal drives (D:, E:).  There is also an external 1E, 4 drive Raid array (F:)  I am in the process of rebuilding Disk 0:3 that failed using Dell OpenManage, with a new same sized Dell OEM drive for this server.  However, it is VERY slow.  Almost 45 min for each % of completion.  I can not take the second external array or server offline b/c of the need for user access (which is actually not much).  Is this a normal speed?  Why so slow? Also, my first rebuild.  Do I have to restart the server or something else in order to have the rebuilt virtual drive array re-appear as a valid drive when the rebuild is 100% complete? Tnx..
PowerEdge830 RAID5 drive Rebuild - Slow