IBM iSCSI Client for Linux Installation and Configuration Instructions

Troubleshooting

This section describes various error conditions that can occur while using the iSCSI client and its command-line tools.

Table 1. Troubleshooting symptoms and recommended actions
Symptom Recommended actions
The device /dev/iscsi does not open.
  1. Verify that you have root permission (su root).
  2. Verify that the device exists by typing ls -l /dev/iscsi and pressing Enter. A list of devices is displayed.

    If you do not see the device in the list, create it by typing mknod /dev/iscsi c 196 0 and pressing Enter.

  3. Verify that the iSCSI client was loaded successfully by typing lsmod and pressing Enter.

Adding a target failed.
  1. Verify your configuration by typing iscsi_check_config /etc/iscsiclient.conf and pressing Enter.
  2. Verify the network connection with the target by typing the following command and pressing Enter:
    ping targetHostName

    where targetHostName is the host name or IP address of the target.

  3. Verify that the target running and operating correctly using the Administrative Console by clicking Storage --> Virtualization and verifying that the correct VLUNs are listed. If the VLUNs are not listed, view the debug messages from the Service and Recovery Console:
    1. Connect to the target through the serial port.
    2. Type iscsi and press Enter.
    3. Type dmesg and press Enter.
  4. Verify that the IP address and log-in parameters for the target are properly specified in the /etc/iscsiclient.conf file.

Removing a target failed, and the message Disks are used or busy is displayed.
  1. Verify that all disks associated with the target that you are attempting to remove are unmounted.
  2. Verify that there are no applications (such as mkfs or fdisk) that are using the disks on the target .

Unresolved symbols are encountered.
  1. Verify that the iSCSI client code matches the version of the Linux kernel source. If it does not, recompile the iSCSI client code for the correct version of Linux.
  2. Verify that /usr/scr/linux points to the current Linux kernel source tree.
  3. Verify that Linux has built-in SCSI support.
  4. Verify that the VLUNs are configured properly in the target.
  5. Verify that the VLUNs are assigned properly in your login.

The iSCSI client driver does not load or unload, and the message Device or resource busy is displayed.
  1. Verify that the iSCSI client is loaded by typing lsmod and pressing Enter.
  2. Verify that the /etc/iscsiclient.conf file exists.
  3. Verify that all file systems using the disks are unmounted.

fdisk gives incorrect sizes for large disks (for example, larger than 500 GB). Upgrade your util-linux code to version 2.10m or later. You can obtain the latest util-linux code from the Web at www.kernel.org.
You receive a SCSI disk error or a SCSI disk I/O error. The connection to the target has been lost. To reconnect to the target:
  1. Unmount all iSCSI drives currently connected to the failed target (for example, unmount /dev/sda1 /mnt).
  2. Type the following command and press Enter:
    echo "scsi remove-single-device host channel ID LUN"
    > /proc/scsi/scsi

    The variables host, channel, ID, and LUN can be determined by typing cat /proc/scsi/scsi and pressing Enter.

  3. Determine and fix the connection problem (for example, reattach the cable or fix the network problem).
  4. Type the following command and press Enter:
    echo "scsi add-single-device host channel ID LUN" > /proc/scsi/scsi

    The variables host, channel, ID, and LUN are the same as those used in step 2.

  5. Run fsck on the lost disk (for example, fsck /dev/sda1).
  6. Remount the drive (for example, mount /dev/sda /mnt).

[ Top of Page | Previous Page | Next Page | Table of Contents ]