The requirement that filesystems must be brought down to add NSD servers or change the order of the server list is very disruptive.
We need to have a maintenance outage very soon to change the order of our existing NSD servers. We will also be expanding our GPFS servers in the near future (~3 months). I wanted to get opinions on adding placeholder entries for these new machines to the server list for each NSD now, even though the machines (and DNS records, etc.) do not yet exist.
For example, the mmchnsd stanza might look like:
The goal is to avoid future filesystem outages for the NSD change when the machines are installed.
I'd like to know:
- Will GPFS let me add a hostname to the server list if that host has not yet been added as a GPFS node?
- How will the absence of the machines affect performance (ie., will there be noticable timeouts if the first "N" hosts in the NSD server list do not exist)?
- Are there other downsides to preparing the filesystem in this way?