| What: /sys/class/nvme/nvmeX/model |
| What: /sys/class/nvme/nvmeX/serial |
| What: /sys/class/nvme/nvmeX/firmware_rev |
| Date: January 2016 |
| KernelVersion: 4.5 |
| Contact: Keith Busch <kbusch@kernel.org> |
| Description: |
| Shows the model, serial number, or firmware revision string |
| of the NVMe controller, as reported in the Identify |
| Controller data structure. |
| |
| What: /sys/class/nvme/nvmeX/cntlid |
| Date: February 2016 |
| KernelVersion: 4.6 |
| Contact: Ming Lin <ming.l@ssi.samsung.com> |
| Description: |
| Shows the controller identifier assigned by the NVMe |
| subsystem. |
| |
| What: /sys/class/nvme/nvmeX/cntrltype |
| What: /sys/class/nvme/nvmeX/dctype |
| Date: February 2022 |
| KernelVersion: 5.18 |
| Contact: Martin Belanger <martin.belanger@dell.com> |
| Description: |
| cntrltype: Shows the controller type. Possible values: "io", |
| "discovery", "admin", "reserved". |
| |
| dctype: Shows the discovery controller type. Possible values: |
| "none", "ddc", "cdc", "reserved". |
| |
| What: /sys/class/nvme/nvmeX/reset_controller |
| Date: November 2015 |
| KernelVersion: 4.5 |
| Contact: Christoph Hellwig <hch@lst.de> |
| Description: |
| Write-only. Writing any value triggers a synchronous |
| controller reset. |
| |
| What: /sys/class/nvme/nvmeX/rescan_controller |
| Date: April 2016 |
| KernelVersion: 4.7 |
| Contact: Keith Busch <kbusch@kernel.org> |
| Description: |
| Write-only. Writing any value triggers a namespace rescan |
| on this controller. |
| |
| What: /sys/class/nvme/nvmeX/transport |
| What: /sys/class/nvme/nvmeX/subsysnqn |
| What: /sys/class/nvme/nvmeX/address |
| What: /sys/class/nvme/nvmeX/delete_controller |
| What: /sys/class/nvme/nvmeX/reconnect_delay |
| What: /sys/class/nvme/nvmeX/ctrl_loss_tmo |
| Date: June 2016 |
| KernelVersion: 4.8 |
| Contact: Ming Lin <ming.l@ssi.samsung.com> |
| Description: |
| Fabrics controller attributes added with NVMe-oF support. |
| |
| transport: Shows the transport type string. Possible values: |
| "pcie", "tcp", "rdma", "fc", "loop". |
| |
| subsysnqn: Shows the NVMe Qualified Name (NQN) of the |
| subsystem this controller belongs to. |
| |
| address: Shows the transport-specific address string. Only |
| available for fabrics controllers. |
| |
| delete_controller: Write-only. Triggers deletion of this |
| fabrics controller. |
| |
| reconnect_delay: Shows or sets the reconnect delay in |
| seconds. Reading returns the delay value, or "off" if |
| disabled. |
| |
| ctrl_loss_tmo: Shows or sets the controller loss timeout in |
| seconds. Reading returns the timeout value, or "off" if |
| infinite reconnects are allowed. Writing a negative value |
| disables the timeout. |
| |
| What: /sys/class/nvme/nvmeX/hostnqn |
| What: /sys/class/nvme/nvmeX/hostid |
| Date: February 2020 |
| KernelVersion: 5.7 |
| Contact: Sagi Grimberg <sagi@grimberg.me> |
| Description: |
| hostnqn: Shows the host NQN used by this fabrics controller. |
| |
| hostid: Shows the host identifier (UUID format) used by this |
| fabrics controller. |
| |
| Only available for fabrics controllers. |
| |
| What: /sys/class/nvme/nvmeX/fast_io_fail_tmo |
| Date: November 2020 |
| KernelVersion: 5.11 |
| Contact: Victor Gladkov <Victor.Gladkov@kioxia.com> |
| Description: |
| Shows or sets the fast I/O fail timeout in seconds. Reading |
| returns the timeout value, or "off" if disabled. Writing a |
| negative value disables the fast I/O fail. Only available |
| for fabrics controllers. |
| |
| What: /sys/class/nvme/nvmeX/kato |
| Date: April 2021 |
| KernelVersion: 5.13 |
| Contact: Hannes Reinecke <hare@suse.de> |
| Description: |
| Shows the Keep Alive Timeout value in milliseconds for |
| this controller. |
| |
| What: /sys/class/nvme/nvmeX/cmb |
| Date: October 2016 |
| KernelVersion: 4.9 |
| Contact: Stephen Bates <sbates@raithlin.com> |
| Description: |
| Shows the Controller Memory Buffer (CMB) register values |
| in format "cmbloc : 0x%08x\ncmbsz : 0x%08x\n". Only |
| visible when the controller has a CMB (cmbsz != 0). |
| PCI transport only. |
| |
| What: /sys/class/nvme/nvmeX/cmbloc |
| What: /sys/class/nvme/nvmeX/cmbsz |
| What: /sys/class/nvme/nvmeX/hmb |
| Date: July 2021 |
| KernelVersion: 5.15 |
| Contact: Keith Busch <kbusch@kernel.org> |
| Description: |
| cmbloc: Shows the CMBLOC register value. |
| |
| cmbsz: Shows the CMBSZ register value. |
| |
| cmbloc and cmbsz are only visible when the controller has |
| a CMB. PCI transport only. |
| |
| hmb: Shows or sets whether the Host Memory Buffer (HMB) is |
| enabled. Reading returns 1 (enabled) or 0 (disabled). |
| Writing 1 enables HMB; writing 0 disables it. Only |
| visible when the controller supports HMB (hmpre != 0). |
| PCI transport only. |
| |
| What: /sys/class/nvme/nvmeX/state |
| Date: November 2016 |
| KernelVersion: 4.11 |
| Contact: Sagi Grimberg <sagi@grimberg.me> |
| Description: |
| Shows the current state of the controller. Possible values: |
| "new", "live", "resetting", "connecting", "deleting", |
| "deleting (no IO)", "dead". |
| |
| What: /sys/class/nvme/nvmeX/numa_node |
| Date: November 2018 |
| KernelVersion: 5.0 |
| Contact: Hannes Reinecke <hare@suse.de> |
| Description: |
| Shows the NUMA node the controller is attached to. |
| |
| What: /sys/class/nvme/nvmeX/queue_count |
| What: /sys/class/nvme/nvmeX/sqsize |
| Date: September 2019 |
| KernelVersion: 5.4 |
| Contact: James Smart <jsmart2021@gmail.com> |
| Description: |
| queue_count: Shows the total number of queues (admin + I/O) |
| for this controller. |
| |
| sqsize: Shows the submission queue size for this controller. |
| |
| What: /sys/class/nvme/nvmeX/dhchap_secret |
| What: /sys/class/nvme/nvmeX/dhchap_ctrl_secret |
| Date: June 2022 |
| KernelVersion: 6.0 |
| Contact: Hannes Reinecke <hare@suse.de> |
| Description: |
| dhchap_secret: Shows or sets the host DH-HMAC-CHAP secret |
| for this controller. Reading returns "none" if not set. |
| Writing must use the "DHHC-1:" key format and triggers |
| re-authentication. |
| |
| dhchap_ctrl_secret: Shows or sets the controller |
| DH-HMAC-CHAP secret for bidirectional authentication. |
| Same format as dhchap_secret. |
| |
| Only available when CONFIG_NVME_HOST_AUTH is enabled and |
| for fabrics controllers. |
| |
| What: /sys/class/nvme/nvmeX/tls_key |
| Date: August 2023 |
| KernelVersion: 6.7 |
| Contact: Hannes Reinecke <hare@suse.de> |
| Description: |
| Shows the serial of the currently active TLS PSK as hex. |
| Returns empty if no TLS key is active. Only available for |
| TCP controllers with TLS or secure concatenation enabled |
| (CONFIG_NVME_TCP_TLS). |
| |
| What: /sys/class/nvme/nvmeX/tls_configured_key |
| Date: July 2024 |
| KernelVersion: 6.12 |
| Contact: Hannes Reinecke <hare@kernel.org> |
| Description: |
| Shows the serial of the configured TLS key. Writing 0 |
| triggers a PSK reauthentication (REPLACETLSPSK) with |
| the target. After reauthentication the returned serial |
| will be the new key. Only available for TCP controllers |
| with secure concatenation enabled (CONFIG_NVME_TCP_TLS). |
| |
| What: /sys/class/nvme/nvmeX/tls_keyring |
| Date: July 2024 |
| KernelVersion: 6.12 |
| Contact: Hannes Reinecke <hare@kernel.org> |
| Description: |
| Shows the TLS keyring description. Only available for TCP |
| controllers with a keyring configured (CONFIG_NVME_TCP_TLS). |
| |
| What: /sys/class/nvme/nvmeX/tls_mode |
| Date: April 2026 |
| KernelVersion: 7.1 |
| Contact: Daniel Wagner <wagi@kernel.org> |
| Description: |
| Shows the TLS mode: "tls" for direct TLS or "concat" for |
| secure concatenation. Only available for TCP controllers |
| with TLS or secure concatenation enabled |
| (CONFIG_NVME_TCP_TLS). |
| |
| What: /sys/class/nvme/nvmeX/passthru_err_log_enabled |
| Date: January 2024 |
| KernelVersion: 6.8 |
| Contact: Alan Adamson <alan.adamson@oracle.com> |
| Description: |
| Shows or sets whether admin passthrough error logging is |
| enabled for this controller. Reading returns "on" or "off". |
| Writing accepts a boolean value. |
| |
| What: /sys/class/nvme/nvmeX/quirks |
| Date: November 2025 |
| KernelVersion: 7.0 |
| Contact: Maurizio Lombardi <mlombard@redhat.com> |
| Description: |
| Shows the active quirk names for this controller, one per |
| line. Shows "none" if no quirks are active. |
| |
| What: /sys/class/nvme/nvmeX/admin_timeout |
| What: /sys/class/nvme/nvmeX/io_timeout |
| Date: May 2026 |
| KernelVersion: 7.2 |
| Contact: Maurizio Lombardi <mlombard@redhat.com> |
| Description: |
| admin_timeout: Shows or sets the admin command timeout in |
| milliseconds. |
| |
| io_timeout: Shows or sets the I/O command timeout in |
| milliseconds. Changes are propagated to all namespace |
| request queues. |
| |
| The value must be nonzero. Only writable after the |
| controller has been started at least once. |
| |
| What: /sys/block/nvmeXnY/uuid |
| What: /sys/block/nvmeXnY/eui |
| What: /sys/block/nvmeXnY/nsid |
| Date: December 2015 |
| KernelVersion: 4.5 |
| Contact: Keith Busch <kbusch@kernel.org> |
| Description: |
| Namespace identification attributes. |
| |
| uuid: Shows the UUID for this namespace. Falls back to |
| showing the NGUID for backward compatibility. Hidden if |
| both are all zeros. |
| |
| eui: Shows the IEEE Extended Unique Identifier (EUI-64). |
| Hidden if all zeros. |
| |
| nsid: Shows the namespace identifier (NSID). |
| |
| What: /sys/block/nvmeXnY/wwid |
| Date: February 2016 |
| KernelVersion: 4.6 |
| Contact: Keith Busch <kbusch@kernel.org> |
| Description: |
| Shows the World Wide Identifier for this namespace. The |
| format depends on available identifiers (in priority |
| order): "uuid.{UUID}", "eui.{NGUID}", "eui.{EUI64}", or |
| "nvme.{VID}-{SERIAL}-{MODEL}-{NSID}". |
| |
| What: /sys/block/nvmeXnY/nguid |
| Date: June 2017 |
| KernelVersion: 4.13 |
| Contact: Johannes Thumshirn <jthumshirn@suse.de> |
| Description: |
| Shows the Namespace Globally Unique Identifier (NGUID). |
| Hidden if the NGUID is all zeros. |
| |
| What: /sys/block/nvmeXcYnZ/ana_grpid |
| What: /sys/block/nvmeXcYnZ/ana_state |
| Date: May 2018 |
| KernelVersion: 4.19 |
| Contact: Christoph Hellwig <hch@lst.de> |
| Description: |
| ana_grpid: Shows the ANA Group ID for this namespace |
| path device. |
| |
| ana_state: Shows the ANA state. Possible values: |
| "optimized", "non-optimized", "inaccessible", |
| "persistent-loss", "change". |
| |
| Only visible when the controller supports ANA. |
| Requires CONFIG_NVME_MULTIPATH. |
| |
| What: /sys/block/nvmeXcYnZ/queue_depth |
| Date: June 2024 |
| KernelVersion: 6.11 |
| Contact: Thomas Song <tsong@purestorage.com> |
| Description: |
| Shows the current active I/O count on this path's |
| controller. Returns empty if iopolicy is not "queue-depth". |
| Requires CONFIG_NVME_MULTIPATH. |
| |
| What: /sys/block/nvmeXcYnZ/numa_nodes |
| Date: January 2025 |
| KernelVersion: 6.15 |
| Contact: Nilay Shroff <nilay@linux.ibm.com> |
| Description: |
| Shows the NUMA node mask for which this path is the |
| currently selected path. Returns empty if iopolicy is not |
| "numa". Requires CONFIG_NVME_MULTIPATH. |
| |
| What: /sys/block/nvmeXnY/delayed_removal_secs |
| Date: May 2025 |
| KernelVersion: 6.16 |
| Contact: Nilay Shroff <nilay@linux.ibm.com> |
| Description: |
| Shows or sets the delayed removal timeout in seconds for |
| the multipath head device. When nonzero, I/O is queued |
| instead of failed when all paths are gone, and head removal |
| is deferred. Only visible on multipath head devices. |
| Requires CONFIG_NVME_MULTIPATH. |
| |
| What: /sys/block/nvmeXnY/csi |
| What: /sys/block/nvmeXnY/metadata_bytes |
| What: /sys/block/nvmeXnY/nuse |
| Date: December 2023 |
| KernelVersion: 6.8 |
| Contact: Daniel Wagner <dwagner@suse.de> |
| Description: |
| csi: Shows the Command Set Identifier for this namespace. |
| |
| metadata_bytes: Shows the metadata size in bytes. |
| |
| nuse: Shows the Namespace Utilization (NUSE) value. Reading |
| triggers an Identify Namespace command to refresh the |
| value (rate-limited to avoid excessive commands). |
| |
| What: /sys/block/nvmeXnY/passthru_err_log_enabled |
| Date: January 2024 |
| KernelVersion: 6.8 |
| Contact: Alan Adamson <alan.adamson@oracle.com> |
| Description: |
| Shows or sets whether I/O passthrough error logging is |
| enabled for this namespace. Reading returns "on" or "off". |
| Writing accepts a boolean value. |
| |
| What: /sys/class/nvme/nvmeX/diag/command_error_count |
| What: /sys/class/nvme/nvmeX/diag/reset_count |
| What: /sys/class/nvme/nvmeX/diag/reconnect_count |
| Date: May 2026 |
| KernelVersion: 7.2 |
| Contact: Nilay Shroff <nilay@linux.ibm.com> |
| Description: |
| Controller diagnostic counters. |
| |
| command_error_count: Admin command error counter. |
| |
| reset_count: Controller reset counter. |
| |
| reconnect_count: Accumulated reconnect counter. Only |
| available for fabrics controllers. |
| |
| All counters can be reset by writing a value. |
| |
| What: /sys/block/nvmeXnY/diag/command_retries_count |
| What: /sys/block/nvmeXnY/diag/command_error_count |
| Date: May 2026 |
| KernelVersion: 7.2 |
| Contact: Nilay Shroff <nilay@linux.ibm.com> |
| Description: |
| Namespace diagnostic counters for non-multipath |
| configurations (when CONFIG_NVME_MULTIPATH is not |
| configured). |
| |
| command_retries_count: I/O command retry counter. |
| |
| command_error_count: I/O command error counter. |
| |
| All counters can be reset by writing any value. |
| |
| What: /sys/block/nvmeXcYnZ/diag/command_retries_count |
| What: /sys/block/nvmeXcYnZ/diag/command_error_count |
| What: /sys/block/nvmeXcYnZ/diag/multipath_failover_count |
| What: /sys/block/nvmeXnY/diag/io_requeue_no_usable_path_count |
| What: /sys/block/nvmeXnY/diag/io_fail_no_available_path_count |
| Date: May 2026 |
| KernelVersion: 7.2 |
| Contact: Nilay Shroff <nilay@linux.ibm.com> |
| Description: |
| Namespace diagnostic counters for multipath |
| configurations (when CONFIG_NVME_MULTIPATH is |
| configured). |
| |
| command_retries_count: I/O command retry counter. |
| |
| command_error_count: I/O command error counter. |
| |
| multipath_failover_count: Multipath failover counter. |
| |
| io_requeue_no_usable_path_count: Counter of I/Os |
| requeued because no usable path was available. |
| |
| io_fail_no_available_path_count: Counter of I/Os |
| failed because no available path existed. |
| |
| All counters can be reset by writing any value. |
| |
| What: /sys/class/nvme-subsystem/nvme-subsysX/model |
| What: /sys/class/nvme-subsystem/nvme-subsysX/serial |
| What: /sys/class/nvme-subsystem/nvme-subsysX/firmware_rev |
| What: /sys/class/nvme-subsystem/nvme-subsysX/subsysnqn |
| Date: November 2017 |
| KernelVersion: 4.15 |
| Contact: Hannes Reinecke <hare@suse.de> |
| Description: |
| Shows the model, serial number, firmware revision, or NQN |
| of the NVMe subsystem. |
| |
| What: /sys/class/nvme-subsystem/nvme-subsysX/iopolicy |
| Date: February 2019 |
| KernelVersion: 5.1 |
| Contact: Hannes Reinecke <hare@suse.de> |
| Description: |
| Shows or sets the multipath I/O path selection policy for |
| this subsystem. Accepted values: "numa", "round-robin", |
| "queue-depth". Changing the policy clears all current path |
| selections. Only available when CONFIG_NVME_MULTIPATH is |
| enabled. |
| |
| What: /sys/class/nvme-subsystem/nvme-subsysX/subsystype |
| Date: September 2021 |
| KernelVersion: 5.16 |
| Contact: Hannes Reinecke <hare@suse.de> |
| Description: |
| Shows the subsystem type. Possible values: "discovery", |
| "nvm", "reserved". |
