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蓝微电子业务存储访问异常缓慢
大概过程如下：
- 检查了主机的多路径配制，正常。
- 使用top,vmstat,iostat查看主机负载，正常。
- 使用dd和cp测试各种情形的读写速度，并与其它磁盘对比，以确定问题磁盘。
- 根据EMC工程师的排查结果，检查光纤交换机配制和状态，相应端口的状态显示正常（确认有问题的光纤线路已经更换，经过几小时的观察，error计数清除后已不再变化）。
- 检查EMC存储和VPLEX的配制，链路状态和问题主机的配制正常。
- 在ERP主机上使用不同的参数挂载磁盘，问题依旧。
最后，尝试在VPLEX上取消了该磁盘的映射，然后重新进行磁盘映射，在EPR系统上重新挂载后，磁盘读写速度恢复正常。
each end device vendor has their own recommendation regarding the fillword settings on the brocade ports connected to their devices. although mode "2" is the formal industry standard (and HDS recommendation), and although many devices will continue to work in the legacy mode "0", most of the vendors recommend using mode "3" because it has a bit more choice and essentially covers modes "1" and "2".
modifying the fillword resets the port, so the port will go offline/online when the command is executed.
The available fillword values are: 0 | -idle-idle Sets IDLE mode in the Link Init and IDLE as the fill word (default). 1 | -arbff-arbff Sets ARB(ff) in the Link Init and ARB(ff) as the fill word. 2 | -idlef-arbff Sets IDLE mode in the Link Init and ARB(ff) as the fill word. 3 | -aa-then-ia Attempts hardware arbff-arbff (mode 1) first. If the attempt fails to go into active state, this command executes software idle-arb (mode 2). Mode 3 is the preferable to modes 1 and 2 as it captures more cases.. The difference is that '3' tries '1' and then '2'.
example: IBM_2499_192:FID128:admin> portcfgshow 1/0 Area Number: 0 Speed Level: AUTO(HW) Fill Word: 3(A-A then SW I-A) AL_PA Offset 13: OFF ------------------- cut ------------------- 2) To change the fillword mode setting for a port use the portcfgfillword command: example (setting fillword mode 3 on blade 1 port 0): portCfgFillWord 1/0 3
References
http://community.brocade.com/t5/Fibre-Channel-SAN/Should-fillword-be-set-to-3-on-all-8Gbps-ports/td-p/4575/page/2 http://www.aixchina.net/home/space.php?uid=39199&do=blog&id=32107