The volume management driver for Storwize family and SAN Volume Controller (SVC) provides OpenStack Compute instances with access to IBM Storwize family or SVC storage systems.

The Storwize family or SVC system must be configured for iSCSI, Fibre Channel, or both. If using iSCSI, each Storwize family or SVC node should have at least one iSCSI IP address. The IBM Storwize/SVC driver uses an iSCSI IP address associated with the volume's preferred node (if available) to attach the volume to the instance, otherwise it uses the first available iSCSI IP address of the system. The driver obtains the iSCSI IP address directly from the storage system; there is no need to provide these iSCSI IP addresses directly to the driver. If using iSCSI, ensure that the compute nodes have iSCSI network access to the Storwize family or SVC system. OpenStack Nova's Grizzly version supports iSCSI multipath. Once this is configured on the Nova host (outside the scope of this documentation), multipath is enabled. If using Fibre Channel (FC), each Storwize family or SVC node should have at least one WWPN port configured. If the storwize_svc_multipath_enabled flag is set to True in the Cinder configuration file, the driver uses all available WWPNs to attach the volume to the instance (details about the configuration flags appear in the next section). If the flag is not set, the driver uses the WWPN associated with the volume's preferred node (if available), otherwise it uses the first available WWPN of the system. The driver obtains the WWPNs directly from the storage system; there is no need to provide these WWPNs directly to the driver. If using FC, ensure that the compute nodes have FC connectivity to the Storwize family or SVC system. If using iSCSI for data access and the storwize_svc_iscsi_chap_enabled is set to True, the driver will associate randomly-generated CHAP secrets with all hosts on the Storwize family system. OpenStack compute nodes use these secrets when creating iSCSI connections. CHAP secrets are added to existing hosts as well as newly-created ones. If the CHAP option is enabled, hosts will not be able to access the storage without the generated secrets. Not all OpenStack Compute drivers support CHAP authentication. Please check compatibility before using. CHAP secrets are passed from OpenStack Block Storage to Compute in clear text. This communication should be secured to ensure that CHAP secrets are not discovered. Each instance of the IBM Storwize/SVC driver allocates all volumes in a single pool. The pool should be created in advance and be provided to the driver using the storwize_svc_volpool_name configuration flag. Details about the configuration flags and how to provide the flags to the driver appear in the next section. The driver requires access to the Storwize family or SVC system management interface. The driver communicates with the management using SSH. The driver should be provided with the Storwize family or SVC management IP using the san_ip flag, and the management port should be provided by the san_ssh_port flag. By default, the port value is configured to be port 22 (SSH). Make sure the compute node running the nova-volume management driver has SSH network access to the storage system. To allow the driver to communicate with the Storwize family or SVC system, you must provide the driver with a user on the storage system. The driver has two authentication methods: password-based authentication and SSH key pair authentication. The user should have an Administrator role. It is suggested to create a new user for the management driver. Please consult with your storage and security administrator regarding the preferred authentication method and how passwords or SSH keys should be stored in a secure manner. When creating a new user on the Storwize or SVC system, make sure the user belongs to the Administrator group or to another group that has an Administrator role. If using password authentication, assign a password to the user on the Storwize or SVC system. The driver configuration flags for the user and password are san_login and san_password, respectively. If you are using the SSH key pair authentication, create SSH private and public keys using the instructions below or by any other method. Associate the public key with the user by uploading the public key: select the "choose file" option in the Storwize family or SVC management GUI under "SSH public key". Alternatively, you may associate the SSH public key using the command line interface; details can be found in the Storwize and SVC documentation. The private key should be provided to the driver using the san_private_key configuration flag. You can create an SSH key pair using OpenSSH, by running: $ ssh-keygen -t rsa The command prompts for a file to save the key pair. For example, if you select 'key' as the filename, two files are created: key and key.pub. The key file holds the private SSH key and key.pub holds the public SSH key. The command also prompts for a pass phrase, which should be empty. The private key file should be provided to the driver using the san_private_key configuration flag. The public key should be uploaded to the Storwize family or SVC system using the storage management GUI or command line interface. Ensure that Cinder has read permissions on the private key file.

Set the volume driver to the Storwize family and SVC driver by setting the volume_driver option in cinder.conf as follows: volume_driver = cinder.volume.drivers.storwize_svc.StorwizeSVCDriver The following options specify default values for all volumes. Some can be over-ridden using volume types, which are described below.

List of configuration flags for Storwize storage and SVC driver

Flag name	Type	Default	Description
san_ip	Required		Management IP or host name
san_ssh_port	Optional	22	Management port
san_login	Required		Management login username
san_password	Required The authentication requires either a password (san_password) or SSH private key (san_private_key). One must be specified. If both are specified, the driver uses only the SSH private key.		Management login password
san_private_key	Required		Management login SSH private key
storwize_svc_volpool_name	Required		Default pool name for volumes
storwize_svc_vol_rsize	Optional	2	Initial physical allocation (percentage) The driver creates thin-provisioned volumes by default. The storwize_svc_vol_rsize flag defines the initial physical allocation percentage for thin-provisioned volumes, or if set to -1, the driver creates full allocated volumes. More details about the available options are available in the Storwize family and SVC documentation.
storwize_svc_vol_warning	Optional	0 (disabled)	Space allocation warning threshold (percentage)
storwize_svc_vol_autoexpand	Optional	True	Enable or disable volume auto expand Defines whether thin-provisioned volumes can be auto expanded by the storage system, a value of True means that auto expansion is enabled, a value of False disables auto expansion. Details about this option can be found in the –autoexpand flag of the Storwize family and SVC command line interface mkvdisk command.
storwize_svc_vol_grainsize	Optional	256	Volume grain size in KB
storwize_svc_vol_compression	Optional	False	Enable or disable Real-time Compression Defines whether Real-time Compression is used for the volumes created with OpenStack. Details on Real-time Compression can be found in the Storwize family and SVC documentation. The Storwize or SVC system must have compression enabled for this feature to work.
storwize_svc_vol_easytier	Optional	True	Enable or disable Easy Tier Defines whether Easy Tier is used for the volumes created with OpenStack. Details on EasyTier can be found in the Storwize family and SVC documentation. The Storwize or SVC system must have Easy Tier enabled for this feature to work.
storwize_svc_vol_iogrp	Optional	0	The I/O group in which to allocate vdisks
storwize_svc_flashcopy_timeout	Optional	120	FlashCopy timeout threshold The driver wait timeout threshold when creating an OpenStack snapshot. This is actually the maximum amount of time that the driver waits for the Storwize family or SVC system to prepare a new FlashCopy mapping. The driver accepts a maximum wait time of 600 seconds (10 minutes). (seconds)
storwize_svc_connection_protocol	Optional	iSCSI	Connection protocol to use (currently supports 'iSCSI' or 'FC')
storwize_svc_iscsi_chap_enabled	Optional	True	Configure CHAP authentication for iSCSI connections
storwize_svc_multipath_enabled	Optional	False	Enable multipath for FC connections Multipath for iSCSI connections requires no storage-side configuration and is enabled if the compute host has multipath configured.
storwize_svc_multihost_enabled	Optional	True	Enable mapping vdisks to multiple hosts This option allows the driver to map a vdisk to more than one host at a time. This scenario occurs during migration of a virtual machine with an attached volume; the volume is simultaneously mapped to both the source and destination compute hosts. If your deployment does not require attaching vdisks to multiple hosts, setting this flag to False will provide added safety.

The IBM Storwize/SVC driver exposes capabilities that can be added to the extra specs of volume types, and used by the filter scheduler to determine placement of new volumes. Make sure to prefix these keys with capabilities: to indicate that the scheduler should use them. The following extra specs are supported: capabilities:volume_backend_name - Specify a specific backend where the volume should be created. The backend name is a concatenation of the name of the IBM Storwize/SVC storage system as shown in lssystem, an underscore, and the name of the pool (mdisk group). For example: capabilities:volume_backend_name=myV7000_openstackpool capabilities:compression_support - Specify a backend according to compression support. A value of True should be used to request a backend that supports compression, and a value of False will request a backend that does not support compression. If you do not have constraints on compression support, do not set this key. Note that specifying True does not enable compression; it only requests that the volume be placed on a backend that supports compression. Example syntax: capabilities:compression_support='<is> True' capabilities:easytier_support - Similar semantics as the compression_support key, but for specifying according to support of the Easy Tier feature. Example syntax: capabilities:easytier_support='<is> True' capabilities:storage_protocol - Specifies the connection protocol used to attach volumes of this type to instances. Legal values are iSCSI and FC. This extra specs value is used for both placement and setting the protocol used for this volume. In the example syntax, note <in> is used as opposed to <is> used in the previous examples. capabilities:storage_protocol='<in> FC' Volume types can also be used to pass options to the IBM Storwize/SVC driver, which over-ride the default values set in the configuration file. Contrary to the previous examples where the "capabilities" scope was used to pass parameters to the Cinder scheduler, options can be passed to the IBM Storwize/SVC driver with the "drivers" scope. The following extra specs keys are supported by the IBM Storwize/SVC driver: rsize warning autoexpand grainsize compression easytier multipath iogrp These keys have the same semantics as their counterparts in the configuration file. They are set similarly; for example, rsize=2 or compression=False. In the following example, we create a volume type to specify a controller that supports iSCSI and compression, to use iSCSI when attaching the volume, and to enable compression: $ cinder type-create compressed $ cinder type-key compressed set capabilities:storage_protocol='<in> iSCSI' capabilities:compression_support='<is> True' drivers:compression=True We can then create a 50GB volume using this type: $ cinder create --display-name "compressed volume" --volume-type compressed 50 Volume types can be used, for example, to provide users with different performance levels (such as, allocating entirely on an HDD tier, using Easy Tier for an HDD-SDD mix, or allocating entirely on an SSD tier) resiliency levels (such as, allocating volumes in pools with different RAID levels) features (such as, enabling/disabling Real-time Compression)

In the context of OpenStack Block Storage's volume migration feature, the IBM Storwize/SVC driver enables the storage's virtualization technology. When migrating a volume from one pool to another, the volume will appear in the destination pool almost immediately, while the storage moves the data in the background. To enable this feature, both pools involved in a given volume migration must have the same values for extent_size. If the pools have different values for extent_size, the data will still be moved directly between the pools (not host-side copy), but the operation will be synchronous. The IBM Storwize/SVC driver allows for extending a volume's size, but only for volumes without snapshots. Snapshots are implemented using FlashCopy with no background copy (space-efficient). Volume clones (volumes created from existing volumes) are implemented with FlashCopy, but with background copy enabled. This means that volume clones are independent, full copies. While this background copy is taking place, attempting to delete or extend the source volume will result in that operation waiting for the copy to complete.