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Chapter 18. Storage
NVMe driver rebased to version 4.17-rc1
NVMedriver has been rebased to upstream version 4.17-rc1, which provides a number of bug fixes and enhancements over the previous version. Notable changes are as follows:
- added error handling improvements for Nonvolatile Memory Express (NVMe) over Remote Direct Memory Access (RDMA)
- added fixes for keeping connections over the RDMA transport alive
Note that the driver does not support the Data Integrity Field/Data Integrity Extension (DIF/DIX) Protection Information implementation, and does not support multipathing over NVMe-over-Fabrics transport. (BZ#1515584)
NVMe/FC is fully supported on Broadcom Emulex Fibre Channel Adapters
The NVMe over Fibre Channel (NVMe/FC) transport type is now fully supported in Initiator mode when used with Broadcom Emulex Fibre Channel 32Gbit adapters.
NVMe over Fibre Channel is an additional fabric transport type for the Nonvolatile Memory Express (NVMe) protocol, in addition to the Remote Direct Memory Access (RDMA) protocol that was previously introduced in Red Hat Enterprise Linux.
To enable NVMe/FC in the
lpfcdriver, edit the
/etc/modprobe.d/lpfc.conffile and add the following option:
This feature was introduced as a Technology Preview in Red Hat Enterprise Linux 7.5. Drivers other than
lpfcstill remain in Technology Preview. See the Technology Previews part for more information.
- Multipath is not supported with NVMe/FC. See https://bugzilla.redhat.com/show_bug.cgi?id=1524966.
- The kernel-alt package does not support NVMe/FC.
kdumpis not supported with NVMe/FC. See https://bugzilla.redhat.com/show_bug.cgi?id=1654433.
- Booting from Storage Area Network (SAN) NVMe/FC is not supported. See https://bugzilla.redhat.com/show_bug.cgi?id=1654435.
- Storage device fencing is not available on NVMe. See https://bugzilla.redhat.com/show_bug.cgi?id=1519009. (BZ#1584753)
DM Multipath now enables blacklisting or whitelisting paths by protocol
Device Mapper Multipath (DM Multipath) now supports the
protocolconfiguration option in the
blacklist_exceptionsconfiguration sections. This enables you to blacklist or whitelist paths based on the protocol they use, such as
nvme. For SCSI devices, you can also specify the transport: for example
%0 wildcard added for the
multipathd show paths format command to show path failures
multipathd show paths formatcommand now supports the
%0wildcard to display path failures. Support for this wildcard makes it easier for users to track which paths have been failing in a multipath device. (BZ#1554516)
all_tg_pt multipath configuration option
devicessections of the
multipath.confconfiguration file now support the
all_tg_ptsparameter, which defaults to
no. If this option is set to
mpathpersistregisters keys it will treat a key registered from one host to one target port as going from one host to all target ports. Some arrays, notably the EMC VNX, treat reservations as between one host and all target ports. Without
mpathpersistworking the same way, it would give reservation conflicts. (BZ#1541116)
Support for Data Integrity Field/Data Integrity Extension (DIF/DIX)
DIF/DIX is fully supported, provided that the hardware vendor has qualified it and provides full support for the particular HBA and storage array configuration on RHEL. DIF/DIX is not supported on other configurations. It is not supported for use on the boot device, and it is not supported on virtualized guests. Red Hat does not support using ASMLib when DIF/DIX is enabled. DIF/DIX is enabled/disabled at the storage device, which involves various layers up to (and including) the application. The method for activating the DIF on storage devices is device-dependent.
For further information on the DIF/DIX feature, see What is DIF/DIX. (BZ#1649493)