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978
March 3rd, 2014 03:00
SP-A and SP-B Interconnectivity
Hi All,
I have experience with NetApp. In NetApp, Filer-A and Filer-B connected through "cluster interconnect cable" and also half of the NVRAM mirrored with partner node. In EMC, i had look physical connectivity and there is no interconnect cable for SP-A and SP-B.
How SP-A and SP-B interconnectivity established? what is CMI and how it works?
Storage Model: Clariion CX4-120 and VNX5100 (Block Only)
Regards,
Dhakshinamoorthy Balasubramanian
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Jyothi_P_Bharat
317 Posts
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March 3rd, 2014 04:00
Hi,
CMI is used for any communication between storage processors. For example, mirroring of write cache happens over the CMI bus. Also, IO operations for ALUA happen over the CMI bus. You can find more details about ALUA in the whitepaper on Powerlink.
Thanks
Jyothi
Steavson
9 Posts
1
March 3rd, 2014 05:00
The CLARiiON Messaging Interface (CMI) carries data and status information between SPs over the high-speed PCI Express bus.
The CMI has gone through several name changes over the years. Current customer documentation refers to the CMI as the CLARiiON Messaging Interface, and is used throughout the materials. Other names include “Communications Messaging Interface and Configuration Management Interface.
On FC-series arrays, even though the CMI is not redundant, it is not an single point of failure. If the CMI fails, one SP shuts down and the remaining SP trespasses all LUNs.
On CX, CX3, and CX4 series arrays, dual CMIs remove the need for SP shutdown in the event of a single CMI failure.
kelleg
4.5K Posts
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March 17th, 2014 13:00
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glen