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Connect a host to EQL groups in separate SANs
Is there a supported and good way to do it?
The setup looks like this:
- Group 1 in subnet A (1Gb SAN, older)
- Group 2 in subnet B (10Gb SAN, newer)
- Host has connections to all subnets through different NICs, is a Windows server, has HIT Kit and working MPIO to group A
- Subnet A and B are physically and logically separate, no traffic can flow directly from one to the other
I'd like to use the host to be able to access and move data on and between both groups (application using host-based mirroring, etc).
HIT/ME only supports one MPIO-setting per host, so that's obviously the first thing to be "not ok" as I'd have to include both subnets A and B.
What catastrophes should I expect if I decide to do it anyway? Will this ever be a supported scenario (and HIT/ME have support for multiple MPIO configurations, one set per group f.ex.)?
Anonymous
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April 19th, 2013 05:00
Hello,
The only downside including both subnets in the HIT MPIO, is that it will periodically attempt to connect to one group with NICs on the other subnet. The connectivity check will fail and just use NICs that can reach the appropriate group.
Anonymous
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April 19th, 2013 06:00
Well it can't put additional load on the array since it's not connecting over those other links.
However, a performance issue would LIKELY result if the subnets were routed. I've seen that when the LAN and SAN were routed together. (Sometimes via a single GbE link) So bandwidth is limited and additional latency is likely. Since LAN switches typically aren't configured or suitable for iSCSI use.
Regards,
mirko.schnellba
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April 19th, 2013 05:00
Thank you for your answer, though it differs greatly from what I heard from Dell support about a year ago. Essential the tech back then told me that having adapters (which could not reach members) included for MPIO would be bad for performance and put additional load on the arrays.
If that's no longer the case / has been wrong all along, I'm a happy camper.