Aix 搭配EMC storage 使用native MPIO的調整方式

Aix 搭配EMC storage 使用native MPIO的調整方式

Default MPIO是使用single lun path , 要改成round robin才會提升disk array io 效能

Device	Attribute	Value
fscsi	fc_err_recov	fast_fail
hdisk	reserve_policy	no_reserve
hdisk	algorithm	round_robin

 以上三個參數，是設定AIX Multipath IO參數，簡稱MPIO的設定，作用是當AIX主機有多條路徑連到後端儲存系統時，

需要在AIX上面做參數的調整，以取得較佳的資料路徑選擇方式。

Ref: https://www.ibm.com/developerworks/community/forums/html/topic?id=77777777-0000-0000-0000-000013773272

http://www-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/TD105839

via this command if no disks are in use:

# chdev -l hdisk5 -a dyntrk=yes -a fc_err_recov=fast_fail

or if the disks are in use:

# chdev -l hdisk5 -a dyntrk=yes -a fc_err_recov=fast_fail -P

chdev -l hdisk5 -a reserve_policy=no_reserve -a algorithm=round_robin

EMC中國研究院

http://weibo.com/emclabschina

EMC中国研究院的官方轻博客

http://qing.blog.sina.com.cn/n/EMC%E4%B8%AD%E5%9B%BD%E7%A0%94%E7%A9%B6%E9%99%A2

很強大的網站~

看來現在各廠都要軟硬兼施了~

HP UX syslog "Rebooting for cluster integrity" powerpath

安裝Oracle RAC 之前, 如果沒先處理好powerpath 等等的multi-path 軟體問題,

可能在dbca 之後一小時內會發生node reboot情形

以下連結供參考Ref:

https://forums.oracle.com/thread/927929

https://forums.oracle.com/thread/993066

https://forums.oracle.com/thread/581397

最後查到這篇才證實了我的猜測

==> 294430.1

LONG LATENCIES TO THE VOTING DISKS : EMC PowerPath path error detection and I/O repost and redirect greater than default misscount 

The most common problems relate to multi-path IO software drivers, and the reconfiguration times resulting from a failure in the IO path.

Hardware and (re)configuration issues that introduce these latencies should be corrected.

Reboot原因說明如下

Disk LUN 在I/O重新導向的狀況下...只要符合以下任一條件, 就會node reboot

Takes more than Disktimeout seconds (200 sec) or

Takes more than Misscount Seconds (30 sec)

* By default Misscount is less than Disktimeout seconds

只有在網路互ping超過misscount或Voting disk超過disktimeout時機器才會reboot.

misscount :   Default Value is 60 Sec (Linux) and 30 Sec in Unix platform

disktimeout : Default Value is 200. (Disk IO)