PowerStore:由于主机端缺少 MPIO 配置,节点重新启动后,单个节点提供 I/O

Summary: 所有主机都配置了两个启动器和四个 iSCSI 会话(两个到节点 B,两个到节点 A)。重新启动之前,两个节点按预期提供 I/O,如性能指标中所示。在两个节点都重新启动且没有其他更改后,节点 B 性能图表将变为零带宽,并且由于主机端缺少多路径 I/O (MPIO) 配置,所有 I/O 都将转到节点 A。

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Symptoms

在节点重新启动之前,两个节点都会处理 I/O。
节点重新启动之前的性能指标

节点重新启动后,I/O 仅发送到节点 A。节点 B iSCSI FE 端口上没有 I/O。  
节点重新启动后的性能指标

Cause

用户的 LINUX 主机多路径配置不包含 PowerStore 信息:
defaults {
                user_friendly_names     no
                find_multipaths                yes
                failback                 10
                no_path_retry                  10
}
blacklist {
                devnode              "^nvme.*"
                devnode "scini*"
                devnode "^rbd[0-9]*"
                devnode "^nbd[0-9]*"
}
# Leave this section in place even if empty
blacklist_exceptions {
}
devices {
                device {
                                vendor                                 "DataCore"
                                product                                "SAN*"
                                path_checker                    "tur"
                                path_grouping_policy    failover
                                failback                 30
                }
                device {
                                vendor                                 "DELL"
                                product                                "MD36xx(i|f)"
                                features                               "2 pg_init_retries 50"
                                hardware_handler          "1 rdac"
                                path_selector                    "round-robin 0"
                                path_grouping_policy    group_by_prio
                                failback                 immediate
                                rr_min_io                            100
                                path_checker                    rdac
                                prio                                        rdac
                                no_path_retry                  30
                }
                device {
                                vendor                                 "DGC"
                                product                                ".*"
                                detect_prio                        yes
                                retain_attached_hw_handler yes
                }
                device {
                                vendor                                 "EMC"
                                product                                "Invista"
                                detect_prio                        yes
                                retain_attached_hw_handler yes
                                path_grouping_policy    group_by_prio
                }
…
PowerStore 未添加到 /etc/multipath.conf。配置中的 /etc/multipath.conf 对于 Linux 主机,应为:
defaults {
  user_friendly_names yes
  disable_changed_wwids yes
}
devices {
  device {
    vendor DellEMC
    product PowerStore
    path_selector "queue-length 0"
    path_grouping_policy group_by_prio
    path_checker tur
   detect_prio yes
   failback immediate
   no_path_retry 3
   rr_min_io_rq 1
   fast_io_fail_tmo 15
   }

在《Dell Host Connectivity Guide for Linux》文档中,它指出要修改 /etc/multipath.conf 文件,如下所示:
* vendor - "DellEMC"
* product - "PowerStore"
* path_selector - "queue-length 0"
* path_grouping_policy -
* "group_by_prio"
* path_checker - "tur"
* detect_prio - "yes"
* failback - "immediate"
* no_path_retry - "3"
* rr_min_io_rq - "1"
* fast_io_fail_tmo - "15"
* max_sectors_kb - "1024"
由于 PowerStore LUN 未添加到 Linux /etc/multipath.conf,多路径未管理 PowerStore 逻辑单元号码 (LUN)。在重新启动事件期间,节点 A 比节点 B 早一分钟启动,然后主机仅将 I/O 发送到节点 A ISCSI 目标端口。此问题并不会影响系统的正常工作。

Resolution

建议用户修改 LINUX 多路径配置。将 PowerStore 添加到 后,在两个节点之间实现 I/O 平衡 /etc/multipath.conf,UI 中的节点 B 性能指标已恢复。

请参阅戴尔支持 上的适用于 Linux 的戴尔主机连接指南
Article Properties
Article Number: 000220440
Article Type: Solution
Last Modified: 06 Mar 2024
Version:  2
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