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2590
July 30th, 2017 10:00
MPIO Failover Query with Server 2016 and Dell SCV2020
I recently installed a Dell SCV2020 SAN using iSCSI at my workplace and as part of the troubleshooting tested the failover as per the installation guidelines.
I basically disabled a NIC whilst doing a transfer and the guide said the transfer shouldn't be interrupted however it did pause for a good minute or so. I can't recall whether I gave up and reenabled the NIC and found it continued or if it eventually continued itself in hindsight but I'll be doing some more testing myself tomorrow.
In any case I was hoping to get some advice on MPIO and what exactly I should be expecting of it. To give you an idea of the setup; I have 2 Dell N2024 Switches each representing their own Fault Domain and each Fault Domain has a connection to each of the controllers on the SCV2020 (it has a second controller for redundancy). And each server has 2 connections (one to each switch).
Each HBA shows as having effectively 4 connections (2 from each Switch) and MPIO is enabled in the OS (Windows Server 2016) and listed as Round Robin. I've confirmed the fail of a controller continues uninterrupted and expected the same to happen when disconnecting the paths. Just incase disabling the Nic Port in the OS caused a problem I did it via the switch too (I couldn't be there to physically unplug it as I was working remotely) and encountered the same behaviour.
In my investigations I've discovered a couple timers around keepalive and iSCSI command but, from what I can see, the Dell guidance is to keep these unchanged.
So I guess ultimately my question is, is this the expected behaviour or should it not pause the transfer of the file at all?
Any advice would be greatly appreciated.
CompellentSanAd
43 Posts
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July 30th, 2017 14:00
I will guess you are using Virtual Ports on your SAN. Please verify this. I would first check if you have everything configured properly based upon this document: en.community.dell.com/.../20437917
Make sure to check Appendix A for timeout settings, and Link Down Time.
FFriet
3 Posts
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January 30th, 2019 01:00