NFS Migration from NS-120 to VNX

Question

I wanted to see if anyone knew of any additional documentation on using Celerra/VNX Replicator to migrate NFS file systems other than 'Migrating Data from an EMC Celerra Array to a VNX Platform Using Celerra Replicator'?  There is a brief section at the end of the guide on NFS.  Going to test first but wanted to see if there were any undocumented issues others may have seen?  There are around 15 NFS exports being mounted on roughly 50 CentOS clients.  Thanks!

jpmorgan17 · Answer

Thanks for the feedback Karl!  Still parsing through the output of the /usr/sbin/showmount output to assist in determing all NFS clients (exports were done by subnet).  So far via spot check all have been mounted via DNS and I think we are going to go with the DNS alias approach.  No VMware on NFS, I will update the thread once we cutover.  Thanks!!

umichklewis · Answer

Most of your issues will be related to NFS client loss of connectivity during the cutover.  That is, when you switchover the replication from the NS120 to the VNX, you will see a loss of connectivity from the clients connected via NFS.  How long the interruption is depends on you.  Are you mounting clients via DNS names or IP address?  Let's say your NS120 NFS exports are ns120.mydomain.com/export and your VNX NFS is vnx.mydomain.com/export.  Unless you choose to change DNS or IP addresses, your NFS clients wlil have to unexport the old (NS120) path, then you run the switchover, then the NFS clients mount the new (VNX) path.  If you plan on using DNS aliases instead, that helps avoiding the unmount/remount - the NFS clients will get 'host unavailable' for a time, then the new DNS name will be available and the mounts will return (manually flushing DNS accelerates this).  If you're exporting NFS shares to VMWare, you'll want to test this out in advance.  In one case, I had to reboot an ESX host because it would not get rid of the old NFS hostname.  Let us know how it goes!