ESX Server 2 could store virtual machines only on SCSI disks and on Fibre Channel SANs. ESX Server 3 can store virtual machines on NAS and iSCSI as well, providing the benefits of virtual infrastructure to low cost storage configurations. iSCSI LUNs, like Fibre Channel LUNs, can be formatted with the VMware file system (VMFS). Each virtual machine will reside in a single directory. Network attached storage (NAS) appliances must present file systems over the NFS protocol for ESX Server to be able to use them. NFS mounts will be used like VMFS, with the ESX Server creating one directory for each virtual machine. |
H/W iSCSI: DHCP is Not Supported
Description: DHCP assigned addresses for the qla4010 are not supported.
Workaround: Use static IP addresses for the iSCSI initiator.
H/W iSCSI: Poor performance when Ethernet SAN is Congested or Drops Packets
Description: When there is any significant packet loss on the network, the qla4010 adapter slows down, the ESX Server reports too many SCSI aborts based on timed out commands, and the virtual machines can no longer function. This packet loss can occur when multiple physical hosts use the same iSCSI target port.
iSCSI CHAP Authentication is Supported on a Per-Initiator (HBA) Basis
Description: When using iSCSI CHAP with ESX Server, customers can create unique name/secret pairs for each HBA on an ESX system that accesses their storage array. The name/secret pair is then set on each HBA port on the given ESX system. Per target (storage array) authentication on the ESX HBA is not supported. In installations with multiple storage arrays, the name/secret for the HBA on the ESX system must be the same on all arrays the system accesses. Bi-directional CHAP is not supported.
iSCSI configuration timeouts in the VI Client
Description: Some multi-step iSCSI configuration changes can take longer than the 30 second timeout defined in the VI Client. If a timeout occurs, some multi-step configuration can changes be incomplete.
Workaround: Change the remote command timeout in the VI client. Select Edit > Client Setting and increase the default timeout to 90 seconds.
Hardware iSCSI: Masking Path Inconsistencies When the Path Policy Is Fixed
Description: This is visible only you use esxcfg-mpath in the command line. If the path policy is fixed for a particular lun, when we mask/unmask the LUN for a particular vmhba, it does not fall back to the original HBA.
Workaround: Manually force the active/preferred path using esxcfg-mpath.
H/W iSCSI: ESX cannot be Installed on LUN 255
Description: ESX Server may encounter an anaconda dump (exception) when installing on H/W iSCSI LUN ID 255.
Workaround: Use a different LUN ID for the boot LUN.
VI Client Screens are Different for Configuring General Properties For H/W and S/W iSCSI
Description: This is expected behavior.
CHAP Secrets are Not Displayed
Description: Upon returning to the CHAP configuration screen after setting the CHAP secret, the secret field displays blank rather than asterisks. However, the secret is set and the issue is only cosmetic.
H/W iSCSI: CHAP Configuration Requires a Card Reset
Description: H/W iSCSI might not automatically re-establish a session when CHAP credentials are set or changed. The card might have to be reset to re-establish a session.
1.Set initiator and CHAP credentials on your iSCSI target or storage array for the HBA. If the HBA iSCSI name and IP address are already set, use that information. If they are not already set, specify the name and address you intend to use.
2.Set the SendTargets discovery address or the static discovery target information on the qla4010 HBA in the ESX system. (Using the VI Client, refer to Chapter 6, Configuring iSCSI Storage in the Server Configuration guide).
3.Set the CHAP Name and Secret on the qla4010 HBA to match the credentials you configured on the storage array. (Chapter 6, Configuring iSCSI Storage).
4.If you have not configured the iSCSI name and network information for the qla4010 HBA, do so now. When you're finished the connection to the storage should be completed. If your storage is not visible, make sure the iSCSI names, IP address, and CHAP credentials configured on both the HBA and iSCSI storage are correct.
5.If you have already configured the iSCSI name and network configuration on the qla4010, you must reset the card to connect to storage. Do this one of three ways:
Reboot the system. All information configured in the qla4010 is retained across a reboot.
Reset the card from the VI Client. Do this by changing the iSCSI name, alias or network configuration and saving it. For example, changing the alias, and saving the change resets the card.
From a shell prompt on the console OS, use the command vmkiscsi-tool -X <vmhba> where <vmhba> is the vmhba of the qla4010 card you want to reset.
H/W iSCSI: HBA Failover is not Supported
Description: H/W iSCSI might not re-establish a session on a failed path, and therefore not allow failback even after the path is restored. This also means ESX servers booted from a single iSCSI path might not recover if the path fails for any length of time.
Workaround: The path can be restored by resetting the card once the storage is available. The path can be restored by removing and then adding the discovery address or static discovery target information for that target.
H/W and S/W initiators are not supported on the same ESX server
Description: If H/W iSCSI is configured, the S/W iSCSI adapter is not displayed on the VI Client configuration page.
S/W iSCSI: Core Dump Partitions
Description: Core dump partitions should not be placed on iSCSI LUNs presented over a software initiator.