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Using the Linux Operating System: RDX Appendix

• Overview

• Linux Compatibility

• Using the RDX with Linux

• Troubleshooting

Overview

This document describes the use of RDX removable disk drives on Linux operating systems. There are two models of the RDX device: an internal SATA version and an external USB version. Both SATA and USB models support Linux.

Linux Compatibility

There are a large number of possible Linux distributions which will support the RDX devices natively.  The Linux distributions listed in the table below have been tested and found compliant (see Table 1).

Table 1. Compatibility

SLES – SUSE Linux Enterprise Server (Novell)

RHEL – Red Hat Enterprise Linux

SLES 9 Service Pack 3 does not support SATA ATAPI devices and therefore does not support the RDX Internal SATA product. 

Using the RDX Drive with Linux

RDX Cartridge File System Considerations

The RDX cartridge is formatted as NTFS at point of sale. NTFS format does not allow writes in a Linux operating system. Your cartridge must be reformatted to a different file system supported by Linux, such as FAT32, ext2, and ext3, etc. Please refer to the man pages for fdisk and mkfs for detailed instructions on how to manipulate partition table and create file systems on Linux.  If creating multiple partitions on a cartridge, see section "Eject" below.

• The choice of the file system also has significant impact on backup performance. Ext3 typically gives the best overall performance.
• The FAT32 file system has a 4GB file size limit which can limit archive sizes when using tar.
• Some system BIOS do not handle FAT32 formatted disk volumes correctly and may hang on boot. This typically occurs when USB boot is enabled in the BIOS. See "System Will Not Complete Boot Process with RDX External" section in "Troubleshooting" for more information.

NOTE: Although mkfs will allow format of un-partitioned media, we recommend always using fdisk to create partitioned media before formatting.  Issues exist with the 2.4 kernel and umount when using un-partitioned media.

Automount

A cartridge must be mounted in order to for it to be accessible by the backup application. Some Linux distributions include pre-configured automount for removable disks, others may require user configuration. Please refer to the man pages for automount for more information.

Eject

If the cartridge is mounted, the eject button on the RDX drive will not work properly. Use the eject command to un-mount and eject the cartridge.

NOTE: The eject command cannot properly handle un-mount if multiple partitions are present on a removable disk. Each mounted partition must be un-mounted manually or the eject command will fail.

Backup With tar

The tar command works with RDX drives by writing the archive to a file on the cartridge. Use the tar -M option to create archives which span multiple cartridges on the RDX drive. For spanning removable disk cartridges use the tar -M -L size option (where size is the cartridge capacity in kilobytes) when creating multiple-volume backups. For more information refer to the man page for tar.

Troubleshooting

SCSI Device Status

To find out whether the RDX drive is recognized by the system, issue the following command:

cat /proc/scsi/scsi

This will print out a list of all the SCSI devices in the system. The list should include any RDX drives recognized by the system.  If the RDX drive is not listed, check cable connections and power supplies (and BIOS settings for the SATA product.) 

e2fsck File System Check Fails

If the e2fsck program is unable to successfully complete the file check of an ext2/ext3 cartridge, check to make sure you have the latest version of e2fsprogs installed. Under certain circumstances, earlier versions (pre 1.35) of e2fsck included with some distribution are unable to complete the file systems check.