Novell LINUX ENTERPRISE SERVER 11 - STORAGE ADMINISTRATION GUIDE 2-23-2010 Administration Manual

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Novell LINUX ENTERPRISE SERVER 11 - STORAGE ADMINISTRATION GUIDE 2-23-2010 Administration Manual Manual pdf 99 page image

Resizing Software RAID Arrays with mdadm1199novdocx (en) 7 January 201011Resizing Software RAID Arrayswith mdadmThis section describes how to increase or reduce the size of a software RAID 1, 4, 5, or 6 devicewith the Multiple Device Administration (mdadm(8)) tool.WARNING: Before starting any of the tasks described in this section, make sure that you have avalid backup of all of the data. Section 11.1, “Understanding the Resizing Process,” on page 99 Section 11.2, “Increasing the Size of a Software RAID,” on page 100 Section 11.3, “Decreasing the Size of a Software RAID,” on page 10411.1 Understanding the Resizing ProcessResizing an existing software RAID device involves increasing or decreasing the space contributedby each component partition. Section 11.1.1, “Guidelines for Resizing a Software RAID,” on page 99 Section 11.1.2, “Overview of Tasks,” on page 10011.1.1 Guidelines for Resizing a Software RAIDThe mdadm(8) tool supports resizing only for software RAID levels 1, 4, 5, and 6. These RAIDlevels provide disk fault tolerance so that one component partition can be removed at a time forresizing. In principle, it is possible to perform a hot resize for RAID partitions, but you must takeextra 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 advantageof the changes in available space on the device. In SUSE® Linux Enterprise Server 11, file systemresizing utilities are available for file systems Ext2, Ext3, and ReiserFS. The utilities supportincreasing and decreasing the size as follows:Table 11-1 File System Support for ResizingResizing 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 SizeExt2 or Ext3 resize2fs Yes, offline only Yes, offline onlyReiserFS resize_reiserfs Yes, online or offline Yes, offline only