Simon MottAll about me
Simon Mott - All about me
Simon Mott

Monthly Archives

2 Articles

Odd behaviour with /etc/mtab being a regular file

by Simon

One of our customers had recently requested a Bare-Metal Restore (BMR) of one of their servers; which is a pretty routine task for us. However, upon bringing the restored server up I’d noticed some odd behaviour with some of its services, notably snmpd.

Our monitoring successfully polls most metrics that we look for, however fails on getting disk statistics and eventually snmpd just starts timing out. Using snmpbulkwalk I could see that I was getting a response right up until midway through the HOST-RESOURCES MIB. It did look to be hanging on mount points and once snmpbulkwalk had timed out, I couldn’t get a successful response from snmpd again. This was also seemingly affecting MariaDB, preventing it from starting, amongst other things.

Growing my Linux RAID5 array

by Simon

Recently I’ve needed to expand my RAID5 array by adding another disk. My experience with mdadm since starting to use it back in 2009 was for RAID1 only so I’ve never really needed to actually expand an array and so I thought I’d document the process here for future reference.

This process should in theory work for RAID4 and RAID6 personailities too, not just RAID5.

My array consists of 4x 3TB WD Red NAS drives in RAID5 for a total of ~9TB of space. I’m not going to cover creating of the array here because its mostly the same as RAID1, this instead will cover how to add a new disk to it and subsequent growing of LVM and ext4 to make use of the extra space. You can see how everything is stacked together in the image below.