EMC VNX driver interacts with configured VNX array. It supports both iSCSI and FC protocol.
The VNX cinder driver performs the volume operations by executing Navisphere CLI (NaviSecCLI) which is a command-line interface used for management, diagnostics, and reporting functions for VNX. It also supports both iSCSI and FC protocol.
storops
version 0.5.7 or higher to interact with VNX.This section contains instructions to prepare the Block Storage nodes to use the EMC VNX driver. You should install the Navisphere CLI and ensure you have correct zoning configurations.
storops
is a Python library that interacts with VNX array through
Navisphere CLI.
Use the following command to install the storops
library:
$ pip install storops
Make sure your have the following software installed for certain features:
Feature | Software Required |
---|---|
All | ThinProvisioning |
All | VNXSnapshots |
FAST cache support | FASTCache |
Create volume with type compressed |
Compression |
Create volume with type deduplicated |
Deduplication |
Required software
You can check the status of your array software in the Software page of Storage System Properties. Here is how it looks like:
For the FC Driver, FC zoning is properly configured between the hosts and the VNX. Check Register FC port with VNX for reference.
For the iSCSI Driver, make sure your VNX iSCSI port is accessible by your hosts. Check Register iSCSI port with VNX for reference.
You can use initiator_auto_registration = True
configuration to avoid
registering the ports manually. Check the detail of the configuration in
Back-end configuration for reference.
If you are trying to setup multipath, refer to Multipath setup.
Make the following changes in the /etc/cinder/cinder.conf
file.
Here is a sample of minimum back-end configuration. See the following sections
for the detail of each option.
Set storage_protocol = iscsi
if iSCSI protocol is used.
[DEFAULT]
enabled_backends = vnx_array1
[vnx_array1]
san_ip = 10.10.72.41
san_login = sysadmin
san_password = sysadmin
naviseccli_path = /opt/Navisphere/bin/naviseccli
volume_driver = cinder.volume.drivers.dell_emc.vnx.driver.VNXDriver
initiator_auto_registration = True
storage_protocol = fc
Here is a sample of a minimum back-end configuration. See following sections
for the detail of each option.
Set storage_protocol = iscsi
if iSCSI protocol is used.
[DEFAULT]
enabled_backends = backendA, backendB
[backendA]
storage_vnx_pool_names = Pool_01_SAS, Pool_02_FLASH
san_ip = 10.10.72.41
storage_vnx_security_file_dir = /etc/secfile/array1
naviseccli_path = /opt/Navisphere/bin/naviseccli
volume_driver = cinder.volume.drivers.dell_emc.vnx.driver.VNXDriver
initiator_auto_registration = True
storage_protocol = fc
[backendB]
storage_vnx_pool_names = Pool_02_SAS
san_ip = 10.10.26.101
san_login = username
san_password = password
naviseccli_path = /opt/Navisphere/bin/naviseccli
volume_driver = cinder.volume.drivers.dell_emc.vnx.driver.VNXDriver
initiator_auto_registration = True
storage_protocol = fc
The value of the option storage_protocol
can be either fc
or iscsi
,
which is case insensitive.
For more details on multiple back ends, see Configure multiple-storage back ends
IP of the VNX Storage Processors
Specify SP A or SP B IP to connect:
san_ip = <IP of VNX Storage Processor>
VNX login credentials
There are two ways to specify the credentials.
Use plain text username and password.
Supply for plain username and password:
san_login = <VNX account with administrator role>
san_password = <password for VNX account>
storage_vnx_authentication_type = global
Valid values for storage_vnx_authentication_type
are: global
(default), local
, and ldap
.
Use Security file.
This approach avoids the plain text password in your cinder configuration file. Supply a security file as below:
storage_vnx_security_file_dir = <path to security file>
Check Unisphere CLI user guide or Authenticate by security file for how to create a security file.
Path to your Unisphere CLI
Specify the absolute path to your naviseccli:
naviseccli_path = /opt/Navisphere/bin/naviseccli
Driver’s storage protocol
For the FC Driver, add the following option:
volume_driver = cinder.volume.drivers.dell_emc.vnx.driver.VNXDriver
storage_protocol = fc
For iSCSI Driver, add the following option:
volume_driver = cinder.volume.drivers.dell_emc.vnx.driver.VNXDriver
storage_protocol = iscsi
Specify the list of pools to be managed, separated by commas. They should already exist in VNX.
storage_vnx_pool_names = pool 1, pool 2
If this value is not specified, all pools of the array will be used.
Initiator auto registration
When initiator_auto_registration
is set to True
, the driver will
automatically register initiators to all working target ports of the VNX array
during volume attaching (The driver will skip those initiators that have
already been registered) if the option io_port_list
is not specified in
the cinder.conf
file.
If the user wants to register the initiators with some specific ports but not register with the other ports, this functionality should be disabled.
When a comma-separated list is given to io_port_list
, the driver will only
register the initiator to the ports specified in the list and only return
target port(s) which belong to the target ports in the io_port_list
instead
of all target ports.
Example for FC ports:
io_port_list = a-1,B-3
a
or B
is Storage Processor, number 1
and 3
are
Port ID.
Example for iSCSI ports:
io_port_list = a-1-0,B-3-0
a
or B
is Storage Processor, the first numbers 1
and 3
are
Port ID and the second number 0
is Virtual Port ID
Note
io_port_list
or not.io_port_list
do not exist in VNX during startup.Some available
volumes may remain in storage group on the VNX array due to
some OpenStack timeout issue. But the VNX array do not allow the user to delete
the volumes which are in storage group. Option
force_delete_lun_in_storagegroup
is introduced to allow the user to delete
the available
volumes in this tricky situation.
When force_delete_lun_in_storagegroup
is set to True
in the back-end
section, the driver will move the volumes out of the storage groups and then
delete them if the user tries to delete the volumes that remain in the storage
group on the VNX array.
The default value of force_delete_lun_in_storagegroup
is False
.
Over subscription allows that the sum of all volume’s capacity (provisioned capacity) to be larger than the pool’s total capacity.
max_over_subscription_ratio
in the back-end section is the ratio of
provisioned capacity over total capacity.
The default value of max_over_subscription_ratio
is 20.0, which means
the provisioned capacity can be 20 times of the total capacity.
If the value of this ratio is set larger than 1.0, the provisioned
capacity can exceed the total capacity.
For volume attaching, the driver has a storage group on VNX for each compute
node hosting the vm instances which are going to consume VNX Block Storage
(using compute node’s host name as storage group’s name). All the volumes
attached to the VM instances in a compute node will be put into the storage
group. If destroy_empty_storage_group
is set to True
, the driver will
remove the empty storage group after its last volume is detached. For data
safety, it does not suggest to set destroy_empty_storage_group=True
unless
the VNX is exclusively managed by one Block Storage node because consistent
lock_path
is required for operation synchronization for this behavior.
Enabling storage group automatic deletion is the precondition of this function.
If initiator_auto_deregistration
is set to True
is set, the driver will
deregister all FC and iSCSI initiators of the host after its storage group is
deleted.
The EMC VNX driver supports FC SAN auto zoning when ZoneManager
is
configured and zoning_mode
is set to fabric
in cinder.conf
.
For ZoneManager configuration, refer to Fibre Channel Zone Manager.
In VNX, there is a limitation on the number of pool volumes that can be created in the system. When the limitation is reached, no more pool volumes can be created even if there is remaining capacity in the storage pool. In other words, if the scheduler dispatches a volume creation request to a back end that has free capacity but reaches the volume limitation, the creation fails.
The default value of check_max_pool_luns_threshold
is False
. When
check_max_pool_luns_threshold=True
, the pool-based back end will check the
limit and will report 0 free capacity to the scheduler if the limit is reached.
So the scheduler will be able to skip this kind of pool-based back end that
runs out of the pool volume number.
iscsi_initiators
is a dictionary of IP addresses of the iSCSI
initiator ports on OpenStack compute and block storage nodes which want to
connect to VNX via iSCSI. If this option is configured, the driver will
leverage this information to find an accessible iSCSI target portal for the
initiator when attaching volume. Otherwise, the iSCSI target portal will be
chosen in a relative random way.
Note
This option is only valid for iSCSI driver.
Here is an example. VNX will connect host1
with 10.0.0.1
and
10.0.0.2
. And it will connect host2
with 10.0.0.3
.
The key name (host1
in the example) should be the output of
hostname command.
iscsi_initiators = {"host1":["10.0.0.1", "10.0.0.2"],"host2":["10.0.0.3"]}
Specify the timeout in minutes for operations like LUN migration, LUN creation, etc. For example, LUN migration is a typical long running operation, which depends on the LUN size and the load of the array. An upper bound in the specific deployment can be set to avoid unnecessary long wait.
The default value for this option is infinite
.
default_timeout = 60
The max_luns_per_storage_group
specify the maximum number of LUNs in a
storage group. Default value is 255. It is also the maximum value supported by
VNX.
If ignore_pool_full_threshold
is set to True
, driver will force LUN
creation even if the full threshold of pool is reached. Default to False
.
Extra specs are used in volume types created in Block Storage as the preferred property of the volume.
The Block Storage scheduler will use extra specs to find the suitable back end for the volume and the Block Storage driver will create the volume based on the properties specified by the extra spec.
Use the following command to create a volume type:
$ openstack volume type create demoVolumeType
Use the following command to update the extra spec of a volume type:
$ openstack volume type set --property provisioning:type=thin thick_provisioning_support='<is> True' demoVolumeType
The following sections describe the VNX extra keys.
Key: provisioning:type
Possible Values:
thick
Volume is fully provisioned.
Run the following commands to create a thick
volume type:
$ openstack volume type create ThickVolumeType
$ openstack volume type set --property provisioning:type=thick thick_provisioning_support='<is> True' ThickVolumeType
thin
Volume is virtually provisioned.
Run the following commands to create a thin
volume type:
$ openstack volume type create ThinVolumeType
$ openstack volume type set --property provisioning:type=thin thin_provisioning_support='<is> True' ThinVolumeType
deduplicated
Volume is thin
and deduplication is enabled. The administrator shall
go to VNX to configure the system level deduplication settings. To
create a deduplicated volume, the VNX Deduplication license must be
activated on VNX, and specify deduplication_support=True
to let Block
Storage scheduler find the proper volume back end.
Run the following commands to create a deduplicated
volume type:
$ openstack volume type create DeduplicatedVolumeType
$ openstack volume type set --property provisioning:type=deduplicated deduplicated_support='<is> True' DeduplicatedVolumeType
compressed
Volume is thin
and compression is enabled. The administrator shall go
to the VNX to configure the system level compression settings. To create
a compressed volume, the VNX Compression license must be activated on
VNX, and use compression_support=True
to let Block Storage scheduler
find a volume back end. VNX does not support creating snapshots on a
compressed volume.
Run the following commands to create a compressed
volume type:
$ openstack volume type create CompressedVolumeType
$ openstack volume type set --property provisioning:type=compressed compression_support='<is> True' CompressedVolumeType
Default: thick
Note
provisioning:type
replaces the old spec key storagetype:provisioning
.
The latter one is obsolete since the Mitaka release.
storagetype:tiering
StartHighThenAuto
Auto
HighestAvailable
LowestAvailable
NoMovement
StartHighThenAuto
VNX supports fully automated storage tiering which requires the FAST license
activated on the VNX. The OpenStack administrator can use the extra spec key
storagetype:tiering
to set the tiering policy of a volume and use the key
fast_support='<is> True'
to let Block Storage scheduler find a volume back
end which manages a VNX with FAST license activated. Here are the five
supported values for the extra spec key storagetype:tiering
:
Run the following commands to create a volume type with tiering policy:
$ openstack volume type create ThinVolumeOnAutoTier
$ openstack volume type set --property provisioning:type=thin storagetype:tiering=Auto fast_support='<is> True' ThinVolumeOnAutoTier
Note
The tiering policy cannot be applied to a deduplicated volume. Tiering policy of the deduplicated LUN align with the settings of the pool.
fast_cache_enabled
True
False
False
VNX has FAST Cache feature which requires the FAST Cache license activated on
the VNX. Volume will be created on the backend with FAST cache enabled when
<is> True
is specified.
pool_name
If the user wants to create a volume on a certain storage pool in a back end that manages multiple pools, a volume type with a extra spec specified storage pool should be created first, then the user can use this volume type to create the volume.
Run the following commands to create the volume type:
$ openstack volume type create HighPerf
$ openstack volume type set --property pool_name=Pool_02_SASFLASH volume_backend_name=vnx_41 HighPerf
Note
DO NOT use the following obsolete extra spec keys:
storagetype:provisioning
storagetype:pool
The user could use os-force_detach action to detach a volume from all its attached hosts. For more detail, please refer to https://developer.openstack.org/api-ref/block-storage/v2/?expanded=force-detach-volume-detail#force-detach-volume
snapcopy
True
or true
False
or false
VNX driver supports snap copy which accelerates the process for creating a copied volume.
By default, the driver will use asynchronous migration support, which will start a VNX migration session. When snap copy is used, driver creates a snapshot and mounts it as a volume for the 2 kinds of operations which will be instant even for large volumes.
To enable this functionality, append --metadata snapcopy=True
when creating cloned volume or creating volume from snapshot.
$ cinder create --source-volid <source-void> --name "cloned_volume" --metadata snapcopy=True
Or
$ cinder create --snapshot-id <snapshot-id> --name "vol_from_snapshot" --metadata snapcopy=True
The newly created volume is a snap copy instead of a full copy. If a full copy is needed, retype or migrate can be used to convert the snap-copy volume to a full-copy volume which may be time-consuming.
You can determine whether the volume is a snap-copy volume or not by
showing its metadata. If the snapcopy
in metadata is True
or true
,
the volume is a snap-copy volume. Otherwise, it is a full-copy volume.
$ cinder metadata-show <volume>
Constraints
The default implementation in Block Storage for non-disruptive volume backup is not efficient since a cloned volume will be created during backup.
The approach of efficient backup is to create a snapshot for the volume and connect this snapshot (a mount point in VNX) to the Block Storage host for volume backup. This eliminates migration time involved in volume clone.
Constraints
in-use
since snapshot cannot be taken from this volume.VNX cinder driver is leveraging the LUN migration from the VNX. LUN migration
is involved in cloning, migrating, retyping, and creating volume from snapshot.
When admin set migrate_rate
in volume’s metadata
, VNX driver can start
migration with specified rate. The available values for the migrate_rate
are high
, asap
, low
and medium
.
The following is an example to set migrate_rate
to asap
:
$ cinder metadata <volume-id> set migrate_rate=asap
After set, any cinder volume operations involving VNX LUN migration will take the value as the migration rate. To restore the migration rate to default, unset the metadata as following:
$ cinder metadata <volume-id> unset migrate_rate
Note
Do not use the asap
migration rate when the system is in production, as the normal
host I/O may be interrupted. Use asap only when the system is offline
(free of any host-level I/O).
Cinder introduces Replication v2.1 support in Mitaka, it supports fail-over and fail-back replication for specific back end. In VNX cinder driver, MirrorView is used to set up replication for the volume.
To enable this feature, you need to set configuration in cinder.conf
as
below:
replication_device = backend_id:<secondary VNX serial number>,
san_ip:192.168.1.2,
san_login:admin,
san_password:admin,
naviseccli_path:/opt/Navisphere/bin/naviseccli,
storage_vnx_authentication_type:global,
storage_vnx_security_file_dir:
Currently, only synchronized mode MirrorView is supported, and one volume
can only have 1 secondary storage system. Therefore, you can have only one
replication_device
presented in driver configuration section.
To create a replication enabled volume, you need to create a volume type:
$ openstack volume type create replication-type
$ openstack volume type set --property replication_enabled="<is> True" replication-type
And then create volume with above volume type:
$ openstack volume create replication-volume --type replication-type --size 1
Supported operations
Create volume
Create cloned volume
Create volume from snapshot
Fail-over volume:
$ cinder failover-host --backend_id <secondary VNX serial number> <hostname>
Fail-back volume:
$ cinder failover-host --backend_id default <hostname>
Requirements
For more information on how to configure, please refer to: MirrorView-Knowledgebook:-Releases-30-–-33
VNX Cinder driver now supports asynchronous migration during volume cloning.
The driver now using asynchronous migration when creating a volume from source as the default cloning method. The driver will return immediately after the migration session starts on the VNX, which dramatically reduces the time before a volume is available for use.
To disable this feature, user can add --metadata async_migrate=False
when
creating new volume from source.
Enabling multipath volume access is recommended for robust data access. The major configuration includes:
multipath-tools
, sysfsutils
and sg3-utils
on the
nodes hosting compute and cinder-volume
services. Check
the operating system manual for the system distribution for specific
installation steps. For Red Hat based distributions, they should be
device-mapper-multipath
, sysfsutils
and sg3_utils
.use_multipath_for_image_xfer=true
in the cinder.conf
file
for each FC/iSCSI back end.iscsi_use_multipath=True
in libvirt
section of the
nova.conf
file. This option is valid for both iSCSI and FC driver.For multipath-tools, here is an EMC recommended sample of
/etc/multipath.conf
file.
user_friendly_names
is not specified in the configuration and thus
it will take the default value no
. It is not recommended to set it
to yes
because it may fail operations such as VM live migration.
blacklist {
# Skip the files under /dev that are definitely not FC/iSCSI devices
# Different system may need different customization
devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
devnode "^hd[a-z][0-9]*"
devnode "^cciss!c[0-9]d[0-9]*[p[0-9]*]"
# Skip LUNZ device from VNX
device {
vendor "DGC"
product "LUNZ"
}
}
defaults {
user_friendly_names no
flush_on_last_del yes
}
devices {
# Device attributed for EMC CLARiiON and VNX series ALUA
device {
vendor "DGC"
product ".*"
product_blacklist "LUNZ"
path_grouping_policy group_by_prio
path_selector "round-robin 0"
path_checker emc_clariion
features "1 queue_if_no_path"
hardware_handler "1 alua"
prio alua
failback immediate
}
}
Note
When multipath is used in OpenStack, multipath faulty devices may come out in Nova-Compute nodes due to different issues (Bug 1336683 is a typical example).
A solution to completely avoid faulty devices has not been found yet.
faulty_device_cleanup.py
mitigates this issue when VNX iSCSI storage is
used. Cloud administrators can deploy the script in all Nova-Compute nodes and
use a CRON job to run the script on each Nova-Compute node periodically so that
faulty devices will not stay too long. Refer to: VNX faulty device
cleanup for
detailed usage and the script.
EMC VNX iSCSI driver caches the iSCSI ports information, so that the user
should restart the cinder-volume
service or wait for seconds (which is
configured by periodic_interval
in the cinder.conf
file) before any
volume attachment operation after changing the iSCSI port configurations.
Otherwise the attachment may fail because the old iSCSI port configurations
were used.
VNX does not support extending the thick volume which has a snapshot. If the
user tries to extend a volume which has a snapshot, the status of the volume
would change to error_extending
.
It is not recommended to deploy the driver on a compute node if cinder
upload-to-image --force True
is used against an in-use volume. Otherwise,
cinder upload-to-image --force True
will terminate the data access of the
vm instance to the volume.
When the driver notices that there is no existing storage group that has the host name as the storage group name, it will create the storage group and also add the compute node’s or Block Storage node’s registered initiators into the storage group.
If the driver notices that the storage group already exists, it will assume that the registered initiators have also been put into it and skip the operations above for better performance.
It is recommended that the storage administrator does not create the storage group manually and instead relies on the driver for the preparation. If the storage administrator needs to create the storage group manually for some special requirements, the correct registered initiators should be put into the storage group as well (otherwise the following volume attaching operations will fail).
EMC VNX driver supports storage-assisted volume migration, when the user starts
migrating with cinder migrate --force-host-copy False <volume_id> <host>
or
cinder migrate <volume_id> <host>
, cinder will try to leverage the VNX’s
native volume migration functionality.
In following scenarios, VNX storage-assisted volume migration will not be triggered:
in-use
volume migration between back ends with different storage
protocol, for example, FC and iSCSI.VNX credentials are necessary when the driver connects to the VNX system.
Credentials in global
, local
and ldap
scopes are supported. There
are two approaches to provide the credentials.
The recommended one is using the Navisphere CLI security file to provide the credentials which can get rid of providing the plain text credentials in the configuration file. Following is the instruction on how to do this.
Find out the Linux user id of the cinder-volume
processes. Assuming the
cinder-volume
service is running by the account cinder
.
Run su
as root user.
In /etc/passwd
file, change
cinder:x:113:120::/var/lib/cinder:/bin/false
to cinder:x:113:120::/var/lib/cinder:/bin/bash
(This temporary change is
to make step 4 work.)
Save the credentials on behalf of cinder
user to a security file
(assuming the array credentials are admin/admin
in global
scope). In
the command below, the -secfilepath
switch is used to specify the
location to save the security file.
# su -l cinder -c \
'/opt/Navisphere/bin/naviseccli -AddUserSecurity -user admin -password admin -scope 0 -secfilepath <location>'
Change cinder:x:113:120::/var/lib/cinder:/bin/bash
back to
cinder:x:113:120::/var/lib/cinder:/bin/false
in /etc/passwd
file.
Remove the credentials options san_login
, san_password
and
storage_vnx_authentication_type
from cinder.conf
file. (normally
it is /etc/cinder/cinder.conf
file). Add option
storage_vnx_security_file_dir
and set its value to the directory path of
your security file generated in the above step. Omit this option if
-secfilepath
is not used in the above step.
Restart the cinder-volume
service to validate the change.
This configuration is only required when initiator_auto_registration=False
.
To access VNX storage, the Compute nodes should be registered on VNX first if initiator auto registration is not enabled.
To perform Copy Image to Volume
and Copy Volume to Image
operations,
the nodes running the cinder-volume
service (Block Storage nodes) must be
registered with the VNX as well.
The steps mentioned below are for the compute nodes. Follow the same steps for the Block Storage nodes also (The steps can be skipped if initiator auto registration is enabled).
20:00:00:24:FF:48:BA:C2:21:00:00:24:FF:48:BA:C2
is the WWN of a
FC initiator port name of the compute node whose host name and IP are
myhost1
and 10.10.61.1
. Register
20:00:00:24:FF:48:BA:C2:21:00:00:24:FF:48:BA:C2
in Unisphere:20:00:00:24:FF:48:BA:C2:21:00:00:24:FF:48:BA:C2
with SP Port A-1
appears.myhost1
10.10.61.1
10.10.61.1
will appear under
as well.wwn
with more ports if needed.This configuration is only required when initiator_auto_registration=False
.
To access VNX storage, the compute nodes should be registered on VNX first if initiator auto registration is not enabled.
To perform Copy Image to Volume
and Copy Volume to Image
operations,
the nodes running the cinder-volume
service (Block Storage nodes) must be
registered with the VNX as well.
The steps mentioned below are for the compute nodes. Follow the same steps for the Block Storage nodes also (The steps can be skipped if initiator auto registration is enabled).
On the compute node with IP address 10.10.61.1
and host name myhost1
,
execute the following commands (assuming 10.10.61.35
is the iSCSI
target):
Start the iSCSI initiator service on the node:
# /etc/init.d/open-iscsi start
Discover the iSCSI target portals on VNX:
# iscsiadm -m discovery -t st -p 10.10.61.35
Change directory to /etc/iscsi
:
# cd /etc/iscsi
Find out the iqn
of the node:
# more initiatorname.iscsi
Log in to VNX from the compute node using the target corresponding to the SPA port:
# iscsiadm -m node -T iqn.1992-04.com.emc:cx.apm01234567890.a0 -p 10.10.61.35 -l
Assume iqn.1993-08.org.debian:01:1a2b3c4d5f6g
is the initiator name of
the compute node. Register iqn.1993-08.org.debian:01:1a2b3c4d5f6g
in
Unisphere:
iqn.1993-08.org.debian:01:1a2b3c4d5f6g
with SP Port A-8v0
appears.myhost1
10.10.61.1
10.10.61.1
will appear under
as well.Log out iSCSI on the node:
# iscsiadm -m node -u
Log in to VNX from the compute node using the target corresponding to the SPB port:
# iscsiadm -m node -T iqn.1992-04.com.emc:cx.apm01234567890.b8 -p 10.10.61.36 -l
In Unisphere
, register the initiator with the SPB port.
Log out iSCSI on the node:
# iscsiadm -m node -u
Register the iqn
with more ports if needed.
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