XenServer Administrator's Guide 4.1.0

Storage

3.5.1. Sample QLogic iSCSI HBA setup

For full details on configuring QLogic Fibre Channel and iSCSI HBAs please refer to the QLogic website.

Once the HBA is physically installed into the XenServer Host use the following steps to configure the HBA:

1. Set the IP networking configuration for the HBA. This example assumes DHCP and HBA port 0. Specify

the appropriate values if using static IP addressing or a multi-port HBA.

/opt/QLogic_Corporation/SANsurferiCLI/iscli –ipdhcp 0

2. Add a persistent iSCSI target to port 0 of the HBA.

/opt/QLogic_Corporation/SANsurferiCLI/iscli --pa 0 <iSCSI target IP address> \

--INAME <iSCSI target IQN>

3. Use the xe sr-probe command to force a rescan of the HBA controller and display available LUNs. See

Section 3.3.2, “Probing an SR ” and Section 3.3.7, “Creating a shared LVM over Fibre Channel or iSCSI

HBA SR (lvmohba) ” for more details.

3.5.2. Removing HBA-based FC or iSCSI device entries

Note

This step is not required. Citrix recommends that only power users perform this process if it is

necessary.

Each HBA-based LUN has a corresponding global device path entry under /dev/disk/by-id and a

standard device path under /dev. To remove the device entries for LUNs no longer in use as SRs use the

following steps:

1. Use sr-forget or sr-destroy as appropriate to remove the SR from the XenServer Host database. See

Section 3.4.1, “Destroying or forgetting a SR ” for details.

2. Remove the zoning configuration within the SAN for the desired LUN to the desired host.

3. Use the sr-probe command to determine the ADAPTER, BUS, TARGET, and LUN values corresponding

to the LUN to be removed. See Section 3.3.2, “Probing an SR ” for details.

4. Remove the device entries with the following command:

echo "1" > /sys/class/scsi_device/<ADAPTER>:<BUS>:<TARGET>:<LUN>/device/delete

Warning

Make absolutely sure you are certain which LUN you are removing. Accidentally removing a LUN

required for host operation, such as the boot or root device, will render the host unusable.

3.6. Virtual disk QoS settings (Enterprise Edition only)

In Enterprise Edition, virtual disks have an optional I/O priority Quality of Service (QoS) setting. This setting

can be made to existing virtual disks with the CLI as described in this section.

In order to enable QoS for disk I/O the SR type underlying the VDI must be an LVM-based volume. QoS will

only take effect therefore on SRs of type Local LVM, LVM over iSCSI and LVM over HBA attached LUNs.