RAID50 mdadm
The following is how to setup a RAID50 array in mdadm. I would suggest using a RAID6 array in it’s place, but this is for demonstration purposes.
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The following is how to setup a RAID50 array in mdadm. I would suggest using a RAID6 array in it’s place, but this is for demonstration purposes.
If you lose more disks than you have parity to protect you from data loss, then you’re array is gone. But, quite often you get a temporary failure of several disks at once (bad cable, or failed HBA); afterwards the RAID superblocks are out of sync and you can no longer start your RAID array. Here’s a couple ways to try to get it working again.
One of the advantages of software RAID is the flexibility it gives you, that would normally only be available from high end (expensive) RAID cards. This includes the ability to grow an existing array (only for certain RAID levels), which means if you run out of space you can easily plug in a new drive and keep going.
If you already have smartmontools installed, it is fairly straightforward to write a Bash script that finds each disk in your computer, checks it’s temperature, and then shutdown the system if the temperature is at a critical level.
SMART monitoring is a good tool to identify a potentially failing disk before it has failed or if it’s behaving strangely.
Have you ever had to wait for a “dd” command? Not knowing what’s happening, when it will finish, or how far along it is? It’s actually quite easy to get dd to write it’s progress to the screen. Just follow along to see what I mean.
A common task from the command line or a cronjob might be to send an email. If you want to send an attachment, you might think that would be very complicated.
If you have a big RAID array, that last thing you want to be doing is always checking your available disk space. Let’s setup a quick script to monitor our shares for us daily and to send an alert when it gets over 90% used.
sSmtp is a very lightweight SMTP server that is perfect for sending out system emails. In this article, I will show you show to use sSMTP to send email through your Gmail account.
Here is a quick guide to setting up RAID5 using mdadm. In theory this should apply to any distro that has mdadm, but I was already running Ubuntu 10.04.