NEWS.md

multipath-tools Release Notes

multipath-tools 0.10.0, 2024/08

User-Visible Changes

• The multipathd show daemon command now shows (reconfigure pending) if a reconfiguration has been triggered but not finished yet.

Other major changes

• Refactored the path checker loop. Paths are now checked for each multipath map in turn, rather than walking linearly through the list of paths. Paths for different multipath maps will be checked at different time offsets in the polling_interval time span, which distributes the load caused by path checking more evenly over time.
• Refactored a significant part of the libmultipath / libdevmapper interface. All functions that retrieve information about DM maps have been converted to use just one worker function, libmp_mapinfo(). This reduces code size while providing more flexibility and efficiency (less device-mapper ioctls). Also, cleanup attributes are used consistently in the libdevmapper-related code.
• Renamed public functions, variables, and macros to comply with the glibc policy for reserved names. For backward compatibility reasons, the exported functions from libmpathcmd and libmpathpersist that start with double underscore are kept as weak symbols. Fixes #91.

Bug fixes

• Fixed bug that caused queueing to be always disabled if flushing a map failed (bug introduced in 0.9.8).
• Fixed failure to remove maps even with deferred_remove (bug introduced in 0.9.9).
• Fixed old mpathpersist bug leading to the error message "configured reservation key doesn't match: 0x0" when reservation_key was configured in the multipaths section of multipath.conf (Fixes #92).
• Fixed output of multipath -t and multipath -T for the options force_sync and retrigger_tries. (Fixes #88)
• Fixed adding maps by WWID in CLI (command add map $WWID).

Other

• Removed hardcoded paths and make them configurable instead. This should improve compatibility e.g. with NixOS.
• Improved handling of paths with changed WWIDs.
• Improved synchronization between kernel state and multipathd's internal state.
• Made map removal more efficient by avoiding unnecessary recursion.
• Added hardware defaults for Huawei storage arrays and XSG1 vendors.
• Use -fexceptions during compilation to make sure cleanup code is executed when threads are cancelled
• Use weak attribute for get_multipath_config() and put_multipath_config() in order to enable linking with -Bsymbolic-non-weak-functions (Fixes #86).
• Fixed CI for ARM/v7
• Fixed directio CI test for real devices, run more "real" tests in CI
• Fixed minor issues detected by coverity.
• Fixed a minor bug in the config file parser (Fixes #93).
• Minor documentation fixes (Fixes #87).

multipath-tools 0.9.9, 2024/05

Important note

It is not recommended to use lvm2 2.03.24 and newer with multipath-tools versions earlier than 0.9.9. See "Other major changes" below.

User-Visible Changes

• Changed realtime scheduling: multipathd used to run at the highest possible realtime priority, 99. This has always been excessive, and on some distributions (e.g. RHEL 8), it hasn't worked at all. It is now possible to set multipathd's real time scheduling by setting the hard limit for RLIMIT_RTPRIO (see getrlimit(2)), which corresponds to the rtprio setting in limits.conf and to LimitRTPRIO= in the systemd unit file. The default in the systemd unit file has been set to 10. If the limit is set to 0, multipathd doesn't attempt to enable real-time scheduling. Otherwise, it will try to set the scheduling priority to the given value. Fixes #82.
• Changed normal scheduling: In order to make sure that multipathd has sufficient priority even if real time scheduling is switched off, the CPUWeight= setting in the unit file is set to 1000. This is necessary because regular nice(2) values have no effect in systems with cgroups enabled.
• Changed handling of max_sectors_kb configuration: multipathd applies the max_sectors_kb setting only during map creation, or when a new path is added to an existing map. The kernel makes sure that the multipath device never has a larger max_sectors_kb value than any of its configured path devices. The reason for this change is that applying max_sectors_kb on live maps can cause IO errors and data loss in rare situations. It can now happen that some path devices have a higher max_sectors_kb value than the map; this is not an error. It is not possible any more to decrease max_sectors_kb in multipath.conf and run multipathd reconfigure to "apply" this setting to the map and its paths. If decreasing the IO size is necessary, either destroy and recreate the map, or remove one path with multipathd del path $PATH, run multipathd reconfigure, and re-add the path with multipathd add path $PATH.
• New wildcard %k: The wildcard %k for max_sectors_kb has been added to the multipathd show paths format and multipathd show maps format commands.
• Changed semantics of flush_on_last_del: The flush_on_last_del option now takes the values always , unused, or never. yes and no are still accepted as aliases for always and unused, respectively. always means that when all paths for a multipath map have been removed, outstanding IO will be failed and the map will be deleted. unused means that this will only happen when the map is not mounted or otherwise opened. never means the map will only be removed if the queue_if_no_path feature is off. This fixes a problem where multipathd could hang when the last path of a queueing map was deleted.
• Better parsing of $map arguments in multipathd interactive shell: The $map argument in commands like resize map $map now accepts a WWID, and poorly chosen map aliases that could be mistaken for device names.
• Added documentation for CLI wildcards. The wildcards used in the show maps format and show paths format commands are documented in the multipathd(8) man page now.
• %s wildcard for paths: this wildcard in show paths format now prints the product revision, too.

Other major changes

• Adapted the dm-mpath udev rules such that they will work with the modified device mapper udev rules (DM_UDEV_RULES_VSN==3, lvm2 >= 2.03.24). They are still compatible with older versions of the device-mapper udev rules (lvm2 < 2.03.24). If lvm2 2.03.24 or newer is installed, it is recommended to update multipath-tools to 0.9.9 or newer. See also LVM2 2.03.24 release notes.

Bug fixes

• Fixed misspelled DM_UDEV_DISABLE_OTHER_RULES_FLAG in 11-dm-mpath.rules
• Always use glibc_basename() to avoid some issues with MUSL libc. Fixes #84.
• Fixed map failure counting for no_path_retry > 0.
• The wildcards for path groups are not available for actual commands and have thus been removed from the show wildcards command output.

Other

• Build: added TGTDIR option to simplify building for a different target host (see README.md).

multipath-tools 0.9.8, 2024/02

User-Visible Changes

• Socket activation via multipathd.socket has been disabled by default because it has undesirable side effects (fixes #76, at least partially).
• The restorequeueing CLI command now only enables queueing if disablequeueing had been sent before.
• Error messages sent from multipathd to the command line client have been improved. The user will now see messages like "map or partition in use" or "device not found" instead of just "fail".

Other Major Changes

• multipathd now tracks the queueing mode of maps in its internal features string. This is helpful to ensure that maps have the desired queuing status. Without this, it could happen that a map remains in queueing state even after the no_path_retry timeout has expired.
• multipathd's map flushing code has been reworked to avoid hangs if there are no paths but outstanding IO. Thus, if multipathd is running, multipath -F can now retry map flushing using the daemon, rather than locally.

Bug Fixes

• A segmentation fault in the 0.9.7 autoresize code has been fixed.
• Fixed a bug introduced in 0.9.6 that had caused map reloads being omitted when path priorities changed.
• Fixed compilation with gcc 14. (Fixes #80)
• Minor fixes for issues detected by coverity.
• Spelling fixes and other minor fixes.

CI

• Enabled -D_FILE_OFFSET_BITS=64 to fix issues with emulated 32-bit environments in the GitHub CI, so that we can now run our CI in arm/v7.
• Added the check-spelling GitHub action.
• Various improvements and updates for the GitHub CI workflows.

multipath-tools 0.9.7, 2023/11

User-Visible Changes

• The options bindings_file, wwids_file and prkeys_file, which were deprecated since 0.8.8, have been removed. The path to these files is now hard-coded to $(statedir) (see below).
• Added max_retries config option to limit SCSI retries.
• Added auto_resize config option to enable resizing multipath maps automatically.
• Added support for handling FPIN-Li events for FC-NVMe.

Other Major Changes

• Rework of alias selection code:
  • strictly avoid using an alias that is already taken.
  • cache bindings table in memory.
  • write bindings file only if changes have been applied, and watch it with inotify.
  • sort aliases in "alias order" by using length+alphabetical sort, allowing more efficient allocation of new aliases

Bug Fixes

• Avoid that multipath -d changes sysfs settings.
• Fix memory and error handling of code using aio in the marginal paths code. and the directio checker (fixes #73).
• Insert compile time settings for paths in man pages correctly.

Other

• Add new compile-time variable statedir which defaults to /etc/multipath.
• Add new compile-time variable etc_prefix as prefix for config file and config dir.
• Compile-time variable usr_prefix now defaults to /usr if prefix is empty.
• Remove check whether multipath is enabled in systemd .wants directories.
• README improvements.

multipath-tools 0.9.6, 2023/09

User-Visible Changes

• Added new path grouping policy group_by_tpg to group paths by their ALUA target port group (TPG).
• Added new configuration parameters detect_pgpolicy (default: yes) and detect_pgpolicy_use_tpg (default: no).
• Add new wildcard %A to print target port group in list paths format command.
• NVMe devices are now ignored if NVMe native multipath is enabled in the kernel.

Other Major Changes

• Prioritizers now use the same timeout logic as path checkers.
• Reload maps if the path groups aren't properly ordered by priority.
• Improve logic for updating path priorities.
• Avoid paths with unknown priority affecting the priority of their path group.

Bug Fixes

• Fix max_sectors_kb for cases where a path is deleted and re-added (Fixes #66).
• Fix handling of dev_loss_tmo in cases where it wasn't explicitly configured.
• Syntax fixes in udev rules (Fixes #69).

Other

• Adapt HITACHI/OPEN- config to work with alua and multibus.
• Build system fixes.

multipath-tools 0.9.5, 2023/04

User-Visible Changes

• Always use directio path checker for Linux TCM (LIO) targets (Fixes #54.
• multipath -u now checks if path devices are already in use (e.g. mounted), and if so, makes them available to systemd immediately.

Other Major Changes

• Persistent reservations are now handled consistently. Previously, whether a PR key was registered for a path depended on the situation in which the path had been first detected by multipathd.

Bug Fixes

• Make sure that if a map device must be renamed and reloaded, both actions actually take place (previously, the map would only be renamed).
• Make sure to always flush IO if a map is resized.
• Avoid incorrectly claiming path devices in find_multipaths smart case for paths that have no valid WWID or for which multipath -u failed.
• Avoid paths failures for ALUA transitioning state (fixes #60.
• Handle persistent reservations correctly even if there are no active paths during map creation.
• Make sure all paths are orphaned if maps are removed.
• Avoid error messages for unsupported device designators in VPD pages.
• Fix a memory leak.
• Honor the global option uxsock_timeout in libmpathpersist (fixes #45).
• Don't fail for devices lacking INQUIRY properties such as "vendor" (fixes #56).
• Remove Also= in multipathd.socket (fixes #65).

CI

• Use Ubuntu 22.04 instead of 18.04.

multipath-tools 0.9.4, 2022/12

Bug Fixes

• Verify device-mapper table configuration strings before passing them to the kernel.
• Fix failure of setprstatus, unsetprstatus and unsetprkey commands sent from libmpathpersist introduced in 0.9.2.
• Fix a memory leak.
• Compilation fixes for some architectures, older compilers, and MUSL libc.
• Fix show paths format %c failure for orphan paths (fixes #49)

Build system changes

• Added a simple autoconf-like mechanism.
• Use "quiet build" by default, verbose build can be enabled using make V=1.
• Reworked the Makefile variables for configuring paths.
• Don't require perl just for installation of man pages.

CI

• True "multi-architecture" workflows are now possible on GitHub workflows, to test compilation and run unit tests on different architectures.
• Containers for test builds are now pulled from ghcr.io rather than from docker hub.

Other

• Updates for the hardware table: PowerMax NVMe, Alletra 5000, FAS/AFF and E/EF.
• Documentation fixes.

multipath-tools 0.9.3, 2022/10

Bug fixes

• Fix segmentation violation caused by different symbol version numbers in libmultipath and libmpathutil (fixes 47.

multipath-tools 0.9.2, 2022/10

User-Visible Changes

• Fix handling of device-mapper queue_mode parameter.
• Enforce queue_mode bio for NVMe/TCP paths.

Other Major Changes

• Rework the command parsing logic in multipathd (CVE-2022-41974).
• Use /run rather than /dev/shm (CVE-2022-41973).
• Check transport protocol for NVMe devices.

Bug Fixes

• Rework feature string handling, fixing bugs for corner cases.
• Fix a race in kpartx partition device creation.
• Fix memory leak in the unix socket listener code.
• Fix a read past end of buffer in the unix socket listener code.
• Fix compilation error with clang 15.

multipath-tools 0.9.1, 2022/09

User-Visible Changes

• multipathd doesn't use libreadline any more due to licensing conflicts, because readline has changed its license to GPL 3.0, which is incompatible with the GPL-2.0-only license of parts of the multipath-tools code base. Therefore the command line editing feature in multipathd is disabled by default. libedit can be used instead of libreadline by setting READLINE=libedit during compilation. READLINE=libreadline can also still be set. Only the new helper program multipathc, which does not contain GPL-2.0 code, is linked with libreadline or libedit. multipathd -k now executes multipathc. Fixes 36.
• As part of the work separating code of conflicting licenses, the multipath library has been split into libmultipath and libmpathutil. The latter can be linked with GPL-3.0 code without licensing conflicts.
• Speed up start of multipath -u and multipath -U.
• Speed up seeking for aliases in systems with lots of alias entries.
• Always use the emc_clariion checker for Clariion/Unity storage arrays.

Bug Fixes

• Avoid checker thread blocking uevents or other requests for an extended amount of time with a huge amount of path devices, by occasionally interrupting the checker loop.
• Fix handling the case where a map ended up with no paths while being updated.
• Fix a segmentation violation in list map format code.
• Fix use-after-free in code handling path WWID changes by sorting the alias table.
• Fix timeout handling in unix socket listener code.
• Fix systemd timers in the initramfs.
• Fix find_multipaths_timeout for unknown hardware.
• Fix multipath -ll output for native NVMe.

Other

• Cleanup code for sysfs access, and sanitize error handling.
• Separation of public and internal APIs in libmpathpersist.
• Build system fixes.
• Spelling fixes.

multipath-tools 0.9.0, 2022/06

User-Visible Changes

• The properties dev_loss_tmo, eh_deadline, and fast_io_fail_tmo can now be set by protocol, in the overrides → protocol section of multipath.conf.
• The config_dir and multipath_dir run-time options, marked deprecated since 0.8.8, have been replaced by the build-time options configdir= and plugindir=, respectively.
• getuid_callout is not supported any more.

Other Major Changes

• The uevent filtering and merging code has been re-written to avoid artificial delays in uevent processing.

Bug fixes

• The delayed_reconfigure logic has been fixed.

Other

• hardware table updates.