Replacing hard drive - do I power down the server?

I got an email from Angela sent through the blog. “Do I need to power down the server to fit/replace a hard drive.”

This is a great question and is going to depend on your server and the disk configuration.

The golden rule is that if it is hot swappable and the drive has failed, it is safe to remove and replace with a new drive.

On the HP servers anything with a purple tab is hot swap (but check with an engineer if you’re not sure). So the process to replace a drive would be:

1. Check drive details (size, speed and relevant part numbers)
2. Remove failed drive. Grab the handle, pull the drive slowly.
3. Plug in replacement drive - slowly letting it slide in - check that the replace drive is compatible and the correct part number for that server/mirrored disk.
4. Monitor drive to check it rebuilds. If it fails to rebuild there could be an issue with your array controller or back plain - the bit that connects everything.

You should be able to check the logs/event logs to see the status of the disk. It normally goes like so.

• Drive failed.
• Drive removed
• A new drive has been installed
• The installed drive has  switched to mode 7 to rebuild.
• Drive rebuild is complete.

If the drive has failed, and the server rebooted, I normally wait until it has finished loading the operating system and is a little less busy.

A quick question - is it safe to replace a 15k drive with a 10k drive. Officially this is not best practice. However, what you will find is that the other drives slow down to run at the same speed as the slowest drive.