Home / server / Questions / 119699
Accepted
Andrew Ensley
Asked: 2010-03-06 12:38:01 +0800 CST

Ubuntu Server Hotswap RAID 1: Hardware or Software?

  • 772

I'm building new servers for a project I'm working on. They will all run Ubuntu Server x64 (10.04 soon) and require a RAID 1 hotswap configuration (just two drives) to minimize downtime.

I'm not worried about Raid performance. The server hardware will have plenty of CPU power, and I'm only doing a RAID 1. My only requirements are:

  1. Everything, including the OS, must be mirrored.
  2. There must be no down-time when a drive fails. I need to be able to swap out the failed drive with another and have the RAID rebuild itself automatically (or maybe by running a simple script).

I'm wondering if the built-in Ubuntu Software RAID can handle this, particularly the hotswap part. 10.04 looks promising.

I'm considering buying the 3Ware 9650SE-2LP-SGL RAID controller, but with the number of servers we're purchasing, that would increase the total price quite a bit.

Any advice at all would be appreciated. Thank you.

ubuntu raid hardware-raid software-raid

3 Answers

  1. Best Answer

    I have hot swapped drives using the software RAID builtin into the Linux kernel on many occasions. You may need to run a command to add the new device. I believe it is possible to make it automatic, but in the places where I use it manually running the command to add the new drive has never been a problem.

    I am not entirely certain that the computer will survive with zero downtime. That may depend on your hard drive controller and how it responds to a drive failure.

    • 4

  2. I think the other posts have answered the question but I have a somewhat related thought to add.

    Since uptime is important in this application. Make sure you're using Puppet and Kickstart for setting up and maintaining the configurations on the servers. Also make sure you have a good backup solution....rsnapshot works pretty good.

    The hardware should be pretty replaceable cogs once you're dealing with any sort of scale of computers. Because you'll eventually have to deal with the following situations....you need a plan on how you're going to deal with them now. Not when it happens.

    • Even with redundant power supplies, raid, etc machines will fail in time.
    • The situation where a client starts to outgrow the hardware they are on....if all the clients are on separate hardware as your dialog to some of the answers to seem to imply.
    • Hardware replacement. In 5 years or so you'll want to replace hardware.
    • 1

  3. Are you sure you need RAID?

    I only ask because you said with the number of server you are purchasing, that controller will increase the cost a lot. So with this many server for a single project, aren't a lot of these servers redundant? Perhaps you would save more money by not getting all those second hard drives?

    • 0