To answer these questions, let me first recap from my older referenced post the traffic flow between the primary and secondary usermapper databases (UMDB).  NOTE: Reference to "primary array" and "secondary array" below is simply reference to the UMDB role configured on the array  User accesses CIFS share on array: "secondary" ====================================== 1) Searches for a local match mapping name/SID <-> UID/GID   2) If it does not exist, then queries primary usermapper (think of secondary as R/O) a) If it exists on "primary", then skip to "c"b) If it does not exist on "primary", as primary usermapper it will generate mapping c) Then, single entry (not entire db) is copied to secondary usermapper  3) or, if it does exist on "secondary", it will be a consequence of step #2 from a previous session by user  NOTE: If it does exist already either on primary or secondary, it is probably being read from secmap cache which saves the system from having to read from the file on disk and instead allows for requests to be serviced from memory where it is cached.   User accesses CIFS share on array: "primary" ==================================== 1) Searches for a local match mapping name/SID <-> UID/GID  2) If it does not exist, then locally (as primary usermapper), creates mapping  3) or, if it does exist, then nothing needs to be done (again, likely being read from secmap cache)  NOTE: In this scenario, there is not any communication between primary and secondary usermapper or, in other words, the primary usermapper does not push its entries to the secondary usermappers.   Back to your questions... just to recap your scenario in regards to the first question:  Before starting migration activity (from NS80 to VNX5700-1):         No, nothing changes in your process.  Again, you could also before your migration activity set NS80 as secondary and VNX5700-1 as primary usermapper with the steps in the older referenced post which saves you from doing it at the very end when your last CIFS server is scheduled to be cut-over.  Either is just as effective though and ensures the VNX5700-1 has all of the existing mappings from the NS80 upon the final cut-over (and more importantly, the same user doesn't have two separate mappings).   In regards to the second question, if you follow the traffic flow for a user that only ever accesses a CIFS share on the array with the primary usermapper, the array with the secondary usermapper won't have a mapping for that user.  Therefore, upon switch/fail-over to an array with the secondary usermapper, the following would not be mapped:  btw, I'll have to figure out how you formatted your response with the inline references to the previous post.
Hello guys,  just need confirmation my procedure will work, here is the plan.  I currently have one NS80 and we purchased two VNX5700.   Site 1  NS80 VNX5700-1  Site 2  VNX5700-2  We are using internal usermapper. Both sites are considered active/active. My plan is to configure VNX5700-1 usermapper as secondary and point to NS80. I just have a couple of CIFS servers that will migrate to VNX5700, the rest will be migrated to Isilon. When i finish migrating everybody off NS80, i will schedule downtime on VNX5700-1 and export usermapper on NS80, delete usermapper on VNX5700-1 and import usermapper from NS80. So at this point VNX5700-1 becomes my primary usermapper. Once that is done i can configure VNX5700-2 as secondary usermapper and point to VNX5700-1.  Since both sites are production i don't really care which one is the primary site. I also don't have to have replication between 5700-1 and 5700-2 right away. Am i missing anything ?  Steps:  1) During downtime    NS80$ server_usermapper server_2 -Export -user /home/nasadmin/users.dbNS80$ server_usermapper server_2 -Export -group /home/nasadmin/groups.db    VNX5700-1$ server_usermapper server_2 -Import -user /home/nasadmin/users.dbVNX5700-1$ server_usermapper server_2 -Import -group /home/nasadmin/groups.db   Thanks
NS80 to VNX migration and usermapper