Few days (a month) back I had faced a strange (amateur) problem in Linux with Amazon EBS volume. For some reason I had to increase the volume size say double the size of current volume attached to an instance.
As a normal (not an “advance” user of Linux) I did the following steps:
Dismounted the device (EBS Volume) by “umount /dev/sdf“.
Logged into AWS console and detached the attached volume from the instance.
Took a snapshot of that EBS volume.
Created another volume from above created snapshot with double the size of the current volume.
Attached the above newly created volume back to the instance.
SSH to the instance and mounted the volume (a handy – “mount /dev/sdf/mnt/ebs“).
Just curious (being a naive Linuxian), I tried to see the size of the volume by running “df -h”.
It shows the size of the volume as the old one.
I confirmed it in the AWS console the size of the new EBS volume is double the size of the original.
Today one of our production machine (in Amazon EC2) was down and I couldn’t bring-up the instance due to unavailability of SSH in PORT 22, connection was refused and I had no clue what to do, after sometime I was able to bring-up the instance – (ok short and sweet).
Though I got it working after some work-around, I wanted to make sure what I did was correct, hence I asked experts in stackoverflow.com – got good advice/suggestion and I hope all set for a fix. BTW, the answer on the question also helped in learning a new stuff called auditd on the disk – a must have tool for system admin.
Okay, the reason why I wanted to pin-down this blog is to show what I did to fix /dev/urandomand how did I get the server up and running. Let me go straight to there.
I always want to share some of the quick-tip like the one below.
Recently when I was working with Amazon Cloud for one of our client I faced a problem when umount (dismount) a volume (EBS – Elastic Block Storage) (OR) detaching from an EC2 instance. I could not dismount the volume, whenever I try to dismount, it throws “umount: … device is busy“. I was like not sure what is going on, why the device is not dismounting from the machine ???.
Dismounting a particular device forcefully, especially a storage volume can cause a serious damage you will end-up losing some important data. I was not sure what should I do, on the other end, the PRESSURE, I have to dismount the volume and re-create another machine.