Hello   I'm not following you here, what do you mean by "the size of the raid is not back to extended"? The size of the array should not change if a drive fails. The virtual disk size is a constant regardless of drive status. If a drive fails that would cause the virtual disk size to be smaller then the disk does not contain redundant data and the array will go into a failed state. If you plan to replace a drive that is being used in an array then you should offline the drive before removing it to reduce the risk of data corruption.   If you insert a blank drive into the system then it should automatically start rebuilding into the array. If it does not automatically rebuild into the array then set it as a hot spare.   Yes, you should expect a 30% decrease in performance during a rebuild or consistency check. Some of our firmware will allow you to adjust the percentage used for these tasks, but most of our controllers have it locked at 30% maximum to avoid the system becoming unusable. A good rule of thumb for a consistency check is once per month. A consistency check is a preemptive measure. Running a consistency check while there is no redundant data is pointless. A consistency check will use redundant data to correct any issues with the array data. Thanks 
Dear all, I'm new to working with servers, raid's and hard drives that can be hot swappable. In our organisation we have two servers. Both in Raid 5 and on Poweredge 2950. One server was one month ago showing a failed hard drive, the other one is showing a removed hard drive, both in the open manage server administrator. On the server that showed failed hard drive I took it out and put it back in to see if it would rebuild. It did but the size of the raid is not back to extended so it must have failed and now I will replace it. However I would like to ask you if I need to do any step in the server before I physically replace it? On the other server. Which step do I follow so it sees the hard drive and adds it to the raid? One final question. In the virtual disk info I saw that I can do a consistency check on the drives. If I start that, will that interfere with working with these servers (meaning should I do it after work hours)? Can there be any problems doing that? If regularly, how often should I do that?  Thanks for help about these! Nitman
Replacing hard drives