Scenario 1: If the drives faulted are in different RAID Groups: Total Drives Faulted: 5 Hot Spare Invoked: 3  We can replace all 5 at the same time 3 will rebuild from Hot Spare and other 2 will rebuild the data from Parity.  Scenario 2: If the drives are faulted in the same RAID Groups: SP Collect Analysis is required for the proper action plan depending what RAID Type was used and other factors.  However, coming back to your question: Yes, it will impact the performance of the storage system depending on the rebuild priority is set. A LUN rebuild is a prioritized operation on the Storage System (SP). The available priorities are: ASAP, High, Medium and Low. Low, Medium and Hight priorities have little effect on the performance of production workload where as ASAP priority compeltes a rebuild in the least amount of time but it may have an adverse effect on the performance.  This is the same for all the CLARiiON Family Models.  For Best Performance Practices you may refer to Knowledge Base Article: emc218359 and EMC CLARiiON Best Practices for Performance and Availability.
hello need a list how many disk can ben changed without impact production, i need the best practice, for instance i have 5 failed disk and only 3 hotpares in active status replacing only 3 of them.  having in my hands the total of 5 replenishment, can i replace all of them at the same time. or there is a maxium limit.  Position of disks, type of RG, priority of rebuild, must be check first before the replacement, but, is there any complete list for all models? in order to not impact production, following best practices? thank you MC.
CX4,AX,VNX, maxium changing multiple failed disks at the same time - without 
impact production