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4.3. 설정 파일 기본값
/etc/multipath.conf
설정 파일에는 다음과 같이 user_friendly_names
매개 변수가 yes
로 설정된 defaults
부분이 포함되어 있습니다.
defaults { user_friendly_names yes }
이는
user_friendly_names
매개 변수의 기본값을 덮어쓰기합니다.
설정 파일에는 설정 기본값 템플릿이 들어 있습니다. 다음과 같이 이 부분에 주석을 답니다.
#defaults { # polling_interval 10 # path_selector "round-robin 0" # path_grouping_policy multibus # uid_attribute ID_SERIAL # prio alua # path_checker readsector0 # rr_min_io 100 # max_fds 8192 # rr_weight priorities # failback immediate # no_path_retry fail # user_friendly_names yes #}
설정 매개변수에 해당하는 기본값을 덮어쓰기하려면, 해당하는 행을 템플릿에서
defaults
부분으로 복사하여 주석 해제 처리를 합니다. 예를 들어, path_grouping_policy
매개 변수를 덮어쓰기하려면 이는 failover
기본값이 아닌 multibus
이어야 하며, 해당 행을 템플릿에서 설정 파일의 초기 defaults
부분으로 복사한 후, 다음과 같이 주석 해제 처리합니다.
defaults { user_friendly_names yes path_grouping_policy multibus }
표 4.1. “멀티패스 설정 기본값 ” describes the attributes that are set in the
defaults
section of the multipath.conf
configuration file. These values are used by DM Multipath unless they are overwritten by the attributes specified in the devices
and multipaths
sections of the multipath.conf
file.
표 4.1. 멀티패스 설정 기본값
속성 | 설명 | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
polling_interval | Specifies the interval between two path checks in seconds. For properly functioning paths, the interval between checks will gradually increase to (4 * polling_interval ). The default value is 5. | |||||||||
multipath_dir | The directory where the dynamic shared objects are stored. The default value is system dependent, commonly /lib/multipath . | |||||||||
find_multipaths |
| |||||||||
reassign_maps | Enable reassigning of device-mapper maps. With this option, The multipathd daemon will remap existing device-mapper maps to always point to the multipath device, not the underlying block devices. Possible values are yes and no . The default value is yes . | |||||||||
verbosity | The default verbosity. Higher values increase the verbosity level. Valid levels are between 0 and 6. The default value is 2 . | |||||||||
path_selector |
| |||||||||
path_grouping_policy |
| |||||||||
prio |
| |||||||||
features |
| |||||||||
path_checker |
| |||||||||
failback |
| |||||||||
rr_min_io | Specifies the number of I/O requests to route to a path before switching to the next path in the current path group. This setting is only for systems running kernels older than 2.6.31. Newer systems should use rr_min_io_rq . The default value is 1000. | |||||||||
rr_min_io_rq | Specifies the number of I/O requests to route to a path before switching to the next path in the current path group, using request-based device-mapper-multipath. This setting should be used on systems running current kernels. On systems running kernels older than 2.6.31, use rr_min_io . The default value is 1. | |||||||||
rr_weight | If set to priorities , then instead of sending rr_min_io requests to a path before calling path_selector to choose the next path, the number of requests to send is determined by rr_min_io times the path's priority, as determined by the prio function. If set to uniform , all path weights are equal. The default value is uniform . | |||||||||
no_path_retry |
| |||||||||
user_friendly_names | If set to yes , specifies that the system should use the /etc/multipath/bindings file to assign a persistent and unique alias to the multipath, in the form of mpath n . If set to no , specifies that the system should use the WWID as the alias for the multipath. In either case, what is specified here will be overridden by any device-specific aliases you specify in the multipaths section of the configuration file. The default value is no . | |||||||||
queue_without_daemon | If set to no , the multipathd daemon will disable queuing for all devices when it is shut down. The default value is no . | |||||||||
flush_on_last_del | If set to yes , the multipathd daemon will disable queuing when the last path to a device has been deleted. The default value is no . | |||||||||
max_fds | Sets the maximum number of open file descriptors that can be opened by multipath and the multipathd daemon. This is equivalent to the ulimit -n command. As of the Red Hat Enterprise Linux 6.3 release, the default value is max , which sets this to the system limit from /proc/sys/fs/nr_open . For earlier releases, if this is not set the maximum number of open file descriptors is taken from the calling process; it is usually 1024. To be safe, this should be set to the maximum number of paths plus 32, if that number is greater than 1024. | |||||||||
checker_timeout | The timeout to use for prioritizers and path checkers that issue SCSI commands with an explicit timeout, in seconds. The default value is taken from sys/block/sdx/device/timeout . | |||||||||
fast_io_fail_tmo | The number of seconds the SCSI layer will wait after a problem has been detected on an FC remote port before failing I/O to devices on that remote port. This value should be smaller than the value of dev_loss_tmo . Setting this to off will disable the timeout. The default value is determined by the OS. The fast_io_fail_tmo option overrides the values of the recovery_tmo and replacement_timeout options. For details, see 4.6절. “iSCSI and DM Multipath overrides”. | |||||||||
dev_loss_tmo | The number of seconds the SCSI layer will wait after a problem has been detected on an FC remote port before removing it from the system. Setting this to infinity will set this to 2147483647 seconds, or 68 years. The default value is determined by the OS. | |||||||||
hw_string_match |
| |||||||||
retain_attached_hw_handler | If this parameter is set to yes and the SCSI layer has already attached a hardware handler to the path device, multipath will not force the device to use the hardware_handler specified by the multipath.conf file. If the SCSI layer has not attached a hardware handler, multipath will continue to use its configured hardware handler as usual. The default value is no . | |||||||||
detect_prio | If this is set to yes , multipath will first check if the device supports ALUA, and if so it will automatically assign the device the alua prioritizer. If the device does not support ALUA, it will determine the prioritizer as it always does. The default value is no . | |||||||||
uid_attribute | Provides a unique path identifier. The default value is ID_SERIAL . | |||||||||
force_sync | (Red Hat Enterprise Linux Release 7.1 and later) If this is set to "yes", it prevents path checkers from running in async mode. This means that only one checker will run at a time. This is useful in the case where many multipathd checkers running in parallel causes significant CPU pressure. The default value is no . | |||||||||
delay_watch_checks | (Red Hat Enterprise Linux Release 7.2 and later) If set to a value greater than 0, the multipathd daemon will watch paths that have recently become valid for the specified number of checks. If they fail again while they are being watched, when they next become valid they will not be used until they have stayed up for the number of consecutive checks specified with delay_wait_checks . This allows you to keep paths that may be unreliable from immediately being put back into use as soon as they come back online. The default value is no . | |||||||||
delay_wait_checks | (Red Hat Enterprise Linux Release 7.2 and later) If set to a value greater than 0, when a device that has recently come back online fails again within the number of checks specified with delay_watch_checks , the next time it comes back online it will be marked and delayed and it will not be used until it has passed the number of checks specified in delay_wait_checks . The default value is no . | |||||||||
ignore_new_boot_devs | (Red Hat Enterprise Linux Release 7.2 and later) If set to yes , when the node is still in the initramfs file system during early boot, multipath will not create any devices whose WWIDs do not already exist in the initramfs copy of the /etc/multipath/wwids . This feature can be used for booting up during installation, when multipath would otherwise attempt to set itself up on devices that it did not claim when they first appeared by means of the udev rules. This parameter can be set to yes or no . If unset, it defaults to no . | |||||||||
retrigger_tries , retrigger_delay | (Red Hat Enterprise Linux Release 7.2 and later) The retrigger_tries and retrigger_delay parameters are used in conjunction to make multipathd retrigger uevents if udev failed to completely process the original ones, leaving the device unusable by multipath. The retrigger_tries parameter sets the number of times that multipath will try to retrigger a uevent if a device has not been completely set up. The retrigger_delay parameter sets the number of seconds between retries. Both of these options accept numbers greater than or equal to zero. Setting the retrigger_tries parameter to zero disables retries. Setting the retrigger_delay parameter to zero causes the uevent to be reissued on the next loop of the path checker. If the retrigger_tries parameter is unset, it defaults to 3. If the retrigger_delay parameter is unset, it defaults to 10. | |||||||||
new_bindings_in_boot | (Red Hat Enterprise Linux Release 7.2 and later) The new_bindings_in_boot parameter is used to keep multipath from giving out a user_friendly_name in the initramfs file system that was already given out by the bindings file in the regular file system, an issue that can arise since the user_friendly_names bindings in the initramfs file system get synced with the bindings in the regular file system only when the initramfs file system is remade. When this parameter is set to no multipath will not create any new bindings in the initramfs file system. If a device does not already have a binding in the initramfs copy of /etc/multipath/bindings , multipath will use its WWID as an alias instead of giving it a user_friendly_name . Later in boot, after the node has mounted the regular filesystem, multipath will give out a user_friendly_name to the device. This parameter can be set to yes or no . If unset, it defaults to no . | |||||||||
config_dir | (Red Hat Enterprise Linux Release 7.2 and later) If set to anything other than "" , multipath will search this directory alphabetically for files ending in ".conf" and it will read configuration information from them, just as if the information were in the /etc/multipath.conf file. This allows you to have one main configuration that you share between machines in addition to a separate machine-specific configuration file or files. The config_dir parameter must either be "" or a fully qualified directory name. This parameter can be set only in the main /etc/multipath.conf file and not in one of the files specified in the config_dir file itself. The default value is /etc/multipath/conf.d . | |||||||||
deferred_remove | If set to yes , multipathd will do a deferred remove instead of a regular remove when the last path device has been deleted. This ensures that if a multipathed device is in use when a regular remove is performed and the remove fails, the device will automatically be removed when the last user closes the device. The default value is no . | |||||||||
log_checker_err | If set to once , multipathd logs the first path checker error at verbosity level 2. Any later errors are logged at verbosity level 3 until the device is restored. If it is set to always , multipathd always logs the path checker error at verbosity level 2. The default value is always . | |||||||||
skip_kpartx | (Red Hat Enterprise Linux Release 7.3 and later) If set to yes , kpartx will not automatically create partitions on the device. This allows users to create a multipath device without creating partitions, even if the device has a partition table. The default value of this option is no . | |||||||||
max_sectors_kb | (Red Hat Enterprise Linux Release 7.4 and later) Sets the max_sectors_kb device queue parameter to the specified value on all underlying paths of a multipath device before the multipath device is first activated. When a multipath device is created, the device inherits the max_sectors_kb value from the path devices. Manually raising this value for the multipath device or lowering this value for the path devices can cause multipath to create I/O operations larger than the path devices allow. Using the max_sectors_kb parameter is an easy way to set these values before a multipath device is created on top of the path devices and prevent invalid-sized I/O operations from being passed. If this parameter is not set by the user, the path devices have it set by their device driver, and the multipath device inherits it from the path devices. | |||||||||
remove_retries | (Red Hat Enterprise Linux Release 7.4 and later) Sets how may times multipath will retry removing a device that is in use. Between each attempt, multipath will sleep 1 second. The default value is 0, which means that multipath will not retry the remove. | |||||||||
disable_changed_wwids | (Red Hat Enterprise Linux Release 7.4 and later) If set to yes and the WWID of a path device changes while it is part of a multipath device, multipath will disable access to the path device until the WWID of the path is restored to the WWID of the multipath device. The default value is no , which does not check if a path's WWID has changed. | |||||||||
detect_path_checker | (Red Hat Enterprise Linux Release 7.4 and later) If set to yes , multipath will try to detect if the device supports ALUA. If so, the device will automatically use the tur path checker. If not, the path_checker will be selected as usual. The default value is no . | |||||||||
reservation_key |
| |||||||||
prkeys_file | (Red Hat Enterprise Linux Release 7.5 and later) The full path name of the prkeys file, which is used by the multipathd daemon to keep track of the reservation key used for a specific WWID when the reservation_key parameter is set to file . The default value is /etc/multipath/prkeys . | |||||||||
all_tg_pt | (Red Hat Enterprise Linux Release 7.6 and later) If this option is set to yes , when mpathpersist registers keys it will treat a key registered from one host to one target port as going from one host to all target ports. This must be set to yes to successfully use mpathpersist on arrays that automatically set and clear registration keys on all target ports from a host, instead of per target port per host. The default value is no . |