Skip to Main Content
Managing RAID on Linux
book

Managing RAID on Linux

by Derek Vadala
December 2002
Intermediate to advanced content levelIntermediate to advanced
260 pages
9h 18m
English
O'Reilly Media, Inc.
Content preview from Managing RAID on Linux

Hybrid Arrays

One of the most important features of software RAID is its ability to use existing arrays as member disks. This property allows you to not only create extremely large arrays, but to combine different RAID levels to achieve different degrees of performance and redundancy. The major benefit of using hybrid arrays is their ability to withstand multiple disk failures.

As I mentioned in Chapter 2, it’s advisable to spread member disks across multiple I/O channels whenever possible. This not only increases array performance but, in the case of a mirror, also helps prevent array failure if an I/O channel becomes unavailable because of a disk controller failure or faulty cabling. For example, imagine that /dev/sda and /dev/sdb are member disks of /dev/md0, a RAID-1, and that they are connected to the same controller A. If controller A fails, then all of /dev/md0 becomes unavailable.

Now imagine that each disk is connected to its own controller. For instance, suppose /dev/sda is connected to controller A and /dev/sdb is connected to controller B. In this case, either controller A or B can fail without crashing /dev/md0 (see Figure 3-5), because the other controller’s disk is still operational.

Using multiple controllers help prevent downtime.
Figure 3-5. Using multiple controllers help prevent downtime.

Dispersing disks among multiple controllers is equally important when working with hybrid arrays. For example, take the case of ...

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.
Start your free trial

You might also like

Linux: Powerful Server Administration

Linux: Powerful Server Administration

Uday Sawant, Oliver Pelz, Jonathan Hobson, William Leemans
Hands-On Linux Administration on Azure - Second Edition

Hands-On Linux Administration on Azure - Second Edition

Rithin Skaria, Kamesh Ganesan, Frederik Vos

Publisher Resources

ISBN: 9780596802035Errata Page