How I/O request is processed in EVA and MSA

[Raja N]

Hi,
Can any one please explain me how I/O request is processed by EVA and MSA(1500/1000) storage controllers.I need step by step process.


Thanks
Raja

[IBaltay]

HI,
e.g. this threads could help you:

MSA 1000 Active/Passive or Active/Active

http://forums13.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1242281198511+28353475&threadId=1296237

EVA Active/Active

http://forums13.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1242281498520+28353475&threadId=1018366

XP multipathing

http://forums13.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1242281607874+28353475&threadId=1295252

[Raja N]

Thanks Baltay.

In active/Passive scenario how I/O requests are sent to exactly active controller though both controllers are connected to the fabric.

[Raja N]

In other words how active controllers are identified and sent I/O requests in active/passive scenario though both the controllers are connected to fabric/host.

[IBaltay]

active/passive
Reads/Writes always via one controller either A or B

active/active
writes always via both controllers to both caches (mirror ports)
good reads via the so called managing controller - negotiated by MPIO ALB
bad reads viac the so called proxy controller - via the mirror port and the managing controller