 As always; make sure you have a backup of your data when making changes to a setup like this, but you should be able to just power down the MD3000i, change the switch to unified mode and power it back up without any issues.    Thanks for the very prompt response DevMgr! I just noticed my post is somewhat redundant of post: [URL] in which it is stated the switch on the MD3000i is "ignored". This was pretty much the consensus among other web articles I found. However, based on my current situation, it appears there is some importance to the position of this switch after all. What we are seeing in the support logs is contention between controller (0) and controller (1) on the MD3000i for "ownership" of both EMMs on the MD1000 enclosure. Again thank you for the prompt response.:emotion-21:
We have been happily using a MD3000i SAN for a little over a year. About a month ago we identified a need to expand beyond the 6.5TB usable capacity; we are down to about 1.2TB free space and anticipate exceeding this reserve capacity with in the next 90 days. To accommodate our needs we recently purchased a fully populated MD1000 expansion shelf with (2) EMMs, (2) SAS cables and Hatachi 600GB SAS drives (the MD3000i is fully populated with Seagate 600GB SAS drives).  Before adding the MD1000, we updated the firmware and NVSRAM on the MD3000i to the latest versions. We also verified the HDD firmware on the Hitachi drives was the most recent version. Our research indicated BOTH the MD3000i and MD1000 enclosures need to be in UNIFIED MODE to successfully add the MD1000 expansion enclosure. This left us with a bit of a quandary, as our production MD3000i SAN was in SPLIT MODE.:emotion-18: After speaking with the tech support representative from the vendor that sold us the MD1000, we decided to leave the 3000 in SPLIT MODE, set the 1000 to UNIFIED MODE and attach it anyway. To make a long story short, the solution "sort of works". We have full access to the additional storage; however, over time we develop "degraded physical path" errors on channel (0,1) and all the odd numbered disks on enclosure (2) (2,1 - 2,3 - 2,5 - etc.). So it appears we must change the MD3000i from split mode to unified mode in order to maintain redundant paths. Here is my question: What are the ramifications to switching the MD3000i from SPLIT MODE to UNIFIED MODE to accommodate the new MD1000 with fully redundant paths? Will the existign disk group and vdisks be adversely affected by this change? Also, what are the ramifications to VMware iSCSI multi-pathing? We simply do not have the capacity to backup the production 3000i at this time and we have over a dozen virtual machines homed on it; so failure is not an option. Recommendations?:emotion-55:
Joining new MD1000 to production MD3000i in "split mode"