Pure Storage iSCSI and Fibre Channel volume drivers¶

Limitations and known issues¶

If you do not set up the nodes hosting instances to use multipathing, all network connectivity will use a single physical port on the array. In addition to significantly limiting the available bandwidth, this means you do not have the high-availability and non-disruptive upgrade benefits provided by FlashArray. Multipathing must be used to take advantage of these benefits.

Supported operations¶

• Create, delete, attach, detach, retype, clone, and extend volumes.
• Create a volume from snapshot.
• Create, list, and delete volume snapshots.
• Create, list, update, and delete consistency groups.
• Create, list, and delete consistency group snapshots.
• Manage and unmanage a volume.
• Manage and unmanage a snapshot.
• Get volume statistics.
• Create a thin provisioned volume.
• Replicate volumes to remote Pure Storage array(s).

Configure OpenStack and Purity¶

You need to configure both your Purity array and your OpenStack cluster.

Volume auto-eradication¶

To enable auto-eradication of deleted volumes, snapshots, and consistency groups on deletion, modify the following option in the cinder.conf file:

pure_eradicate_on_delete = true

By default, auto-eradication is disabled and all deleted volumes, snapshots, and consistency groups are retained on the Pure Storage array in a recoverable state for 24 hours from time of deletion.

SSL certification¶

To enable SSL certificate validation, modify the following option in the cinder.conf file:

driver_ssl_cert_verify = true

By default, SSL certificate validation is disabled.

To specify a non-default path to CA_Bundle file or directory with certificates of trusted CAs:

driver_ssl_cert_path = Certificate path

Replication configuration¶

Add the following to the back-end specification to specify another Flash Array to replicate to:

[puredriver-1]
replication_device = backend_id:PURE2_NAME,san_ip:IP_PURE2_MGMT,api_token:PURE2_API_TOKEN

Where PURE2_NAME is the name of the remote Pure Storage system, IP_PURE2_MGMT is the management IP address of the remote array, and PURE2_API_TOKEN is the Purity Authorization token of the remote array.

Note that more than one replication_device line can be added to allow for multi-target device replication.

A volume is only replicated if the volume is of a volume-type that has the extra spec replication_enabled set to <is> True.

To create a volume type that specifies replication to remote back ends:

$ openstack volume type create ReplicationType
$ openstack volume type set --property replication_enabled='<is> True' ReplicationType

The following table contains the optional configuration parameters available for replication configuration with the Pure Storage array.

Automatic thin-provisioning/oversubscription ratio¶

To enable this feature where we calculate the array oversubscription ratio as (total provisioned/actual used), add the following option in the cinder.conf file:

[puredriver-1]
pure_automatic_max_oversubscription_ratio = True

By default, this is disabled and we honor the hard-coded configuration option max_over_subscription_ratio.

Scheduling metrics¶

A large number of metrics are reported by the volume driver which can be useful in implementing more control over volume placement in multi-backend environments using the driver filter and weighter methods.

Metrics reported include, but are not limited to:

total_capacity_gb
free_capacity_gb
provisioned_capacity
total_volumes
total_snapshots
total_hosts
total_pgroups
writes_per_sec
reads_per_sec
input_per_sec
output_per_sec
usec_per_read_op
usec_per_read_op
queue_depth

In conjunction with QOS extra-specs, you can create very complex algorithms to manage volume placement. More detailed documentation on this is available in other external documentation.