Novell LINUX ENTERPRISE SERVER 11 - STORAGE ADMINISTRATION GUIDE 2-23-2010, Руководство администратора, Страница: 99 / 140

Resizing Software RAID Arrays with mdadm
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Resizing Software RAID Arrays
with mdadm
This section describes how to increase or reduce the size of a software RAID 1, 4, 5, or 6 device
with the Multiple Device Administration (
mdadm(8)
) tool.
WARNING: Before starting any of the tasks described in this section, make sure that you have a
valid backup of all of the data.
Š
Section 11.1, “Understanding the Resizing Process,” on page 99
Š
Section 11.2, “Increasing the Size of a Software RAID,” on page 100
Š
Section 11.3, “Decreasing the Size of a Software RAID,” on page 104
11.1 Understanding the Resizing Process
Resizing an existing software RAID device involves increasing or decreasing the space contributed
by each component partition.
Š Section 11.1.1, “Guidelines for Resizing a Software RAID,” on page 99
Š
Section 11.1.2, “Overview of Tasks,” on page 100
11.1.1 Guidelines for Resizing a Software RAID
The
mdadm(8)
tool supports resizing only for software RAID levels 1, 4, 5, and 6. These RAID
levels provide disk fault tolerance so that one component partition can be removed at a time for
resizing. In principle, it is possible to perform a hot resize for RAID partitions, but you must take
extra care for your data when doing so.
The file system that resides on the RAID must also be able to be resized in order to take advantage
of the changes in available space on the device. In SUSE
®
Linux Enterprise Server 11, file system
resizing utilities are available for file systems Ext2, Ext3, and ReiserFS. The utilities support
increasing and decreasing the size as follows:
Table 11-1
File System Support for Resizing
Resizing any partition or file system involves some risks that can potentially result in losing data.
WARNING: To avoid data loss, make sure to back up your data before you begin any resizing task.
File System Utility Increase Size Decrease Size
Ext2 or Ext3 resize2fs Yes, offline only Yes, offline only
ReiserFS resize_reiserfs Yes, online or offline Yes, offline only