Managing Multipath I/O for Devices
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Managing Multipath I/O for
Devices
This section discusses how to configure multiple paths between the servers and storage devices for
automatic failover and optional load balancing.
Section 5.1, “Understanding Multipathing,” on page 41
Section 5.2, “Before You Begin,” on page 44
Section 5.3, “Adding multipathd to the Boot Sequence,” on page 46
Section 5.4, “Starting Multipath I/O Services,” on page 46
Section 5.5, “Configuring Time-Out Settings for the HBA,” on page 46
Section 5.6, “Configuring Multipath I/O for the Root Device,” on page 47
Section 5.7, “Scanning for New Devices without Rebooting,” on page 47
Section 5.8, “Configuring Multipathing for an Existing Software RAID,” on page 48
Section 5.9, “Configuring User-Friendly Names in the /etc/multipath.conf File,” on page 49
Section 5.10, “Managing I/O in Error Situations,” on page 50
Section 5.11, “Resolving Stalled I/O,” on page 50
Section 5.12, “Additional Information,” on page 51
Section 5.13, “What’s Next,” on page 51
5.1 Understanding Multipathing
Section 5.1.1, “What Is Multipathing?,” on page 41
Section 5.1.2, “Benefits of Multipathing,” on page 42
Section 5.1.3, “Guidelines for Multipathing,” on page 42
Section 5.1.4, “Device Mapper,” on page 42
Section 5.1.5, “Device Mapper Multipath I/O Module,” on page 43
Section 5.1.6, “Multipath Tools,” on page 44
5.1.1 What Is Multipathing?
Multipathing is the ability of a server to communicate with the same physical or logical storage
device across multiple physical paths between host bus adapters in the server and the storage
controllers for the device, typically in Fibre Channel (FC) or iSCSI SAN environments. You can
also achieve multiple connections with direct attached storage for SCSI connections. Multipathing
provides connection fault tolerance and can optionally provide load balancing across the available
connections.
Multipathing is managed at the device level. It is not possible to manage connections to Linux
partitions contained in the device. You can combine multiple devices to create a software RAID or
volumes as logical devices, but the physical device itself is managed at a lower level.
Summary of Contents for LINUX ENTERPRISE SERVER 10 - STORAGE ADMINISTRATION GUIDE FOR EVMS
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