First I'll give some details about my server:-

Dell PowerEdge T710
2x 6 core Intel Xeon CPU's
192GB RAM
8x 2TB SAS drives configured as raid 5
OS = Headless Ubuntu Server 18.04 LTS

Here's the question, I have an orange light on one of my SAS drives, and I need to replace it, I've looked everywhere on the net and all that shows is how to change out the drive(s) using windows software to take a drive offline.

I can't just simply press a button to open the latch and just pull the drive out, there has to be a way in Ubuntu to prepare the system ready to take the drive offline, and when a new drive inserted, to auto scan and rebuild the raid for that drive, without powering down the server.

Well, it may just be that easy, but it depends on your server. Is the RAID5 array hardware or software? Does it have a parity drive? And does the server itself support hot-plugging of drives? If it is a hardware RAID with a parity drive and hot-pluggable, then all you do need to do is pop it out and shove another one in. But this depends on the hardware and how you have things configured...you may very well have to power down the box to remove the drive no matter what. Reference the server manual.

Good advice here for a software RAID: https://askubuntu.com/questions/9922...-raid-5-system

But **TAKE BACKUPS FIRST**, no matter what you do! And personally, I'd plan on doing this after hours, just in case things go pear shaped, and you have to totally rebuild the array, and reload from backups. Easier to do alone at the office alone, than with users breathing down your neck, because they can't work.

The RAID5 array is configured from firmware during a POST, pressing CTRL-C to access the SAS and RAID configuration screens, and yes there is a parity drive.

Yep, I intend to do the backups and drive change an hour after everyone has gone home.

After looking through the PERC 6, RAID controller card manual, it seems even though the drives are hot swappable, they can't just be pulled, the server has to be rebooted, then during POST pressing CTRL-C to enter the PERC configuration screen, then select the drive that has the error, and issue the 'offline' command, then wait while the system prepares for the drive to go offline, then selecting that drive again, clicking on 'Replace -> Start' powers off the drive ready for removal, then while the PERC screen is still up, replace the drive, and select 'Replace -> Stop', this will spin up the drive and when the status shows, 'ready', set drive to online, then exit the PERC screen which results in a warning to soft reboot using CTRL-ALT-DEL.

Here's to crossing my fingers, hoping it all goes smooth, and I don't need to rebuild the array.

My server used to have Windoze server 20012 with all the Dell software, but as I hate and despise windoze I installed headless Ubuntu server, with admin access via internal LAN only SSH via PuTTY, and all I need now is iDRACS6 Enterprise module and I can completely control all aspects of the server via a KVM.

Gotta love hardware like that. But at least a simple reboot and 30 minutes downtime may be all you have. Good luck.