December 2002
Intermediate to advanced
260 pages
9h 18m
English
Content preview from Managing RAID on LinuxBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Finishing Touches
If you use mdadm to create arrays, then you
should probably take a minute to create an
/etc/mdadm.conf file before you move on. First,
create the file /etc/mdadm.conf, using any editor
and a DEVICE line that lists all RAID member disks.
On my system, for example, I create the file with the following
line:
DEVICE /dev/sd*
This means that mdadm will examine all the sd device files on my system (/dev/sdb1 through /dev/sdh1) when looking for member disks. Next, you should execute mdadm with the --detail and --scan options to generate array lines and redirect the output so that it is appended to /etc/mdadm.conf.
# mdadm --detail --scan >> /etc/mdadm.confYou should be left with an mdadm.conf file
that contains the DEVICE line you created, plus an
ARRAY line for each active RAID.
# cat /etc/mdadm.conf
DEVICE /dev/sd{b,c,d,e,f,g,h}1
ARRAY /dev/md1 level=raid0 num-devices=5 \
UUID=66b78871:dc09da58:60f57124:978e5dbf
ARRAY /dev/md0 level=raid1 num-devices=2 \
UUID=b047f5a4:b6f459e0:fb04a323:46a1a012Arrays that are not active will not be scanned by mdadm. Remember that you aren’t obligated to create an mdadm.conf file, but it will make managing arrays using mdadm much easier. Now you can start both arrays with a simple command:
# mdadm -As
mdadm: /dev/md1 has been started with 5 drives.
mdadm: /dev/md0 has been started with 2 drives.Without the configuration file, you would need to know at least which disks were members. And you would need to execute a command such as the following ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.