[j-nsp] ISSU timeouts on MX upgrades due to large routing tables?

[Clarke Morledge]

I was curious to know if anyone has run into any issues with large routing 
tables on an MX causing ISSU upgrades to fail?

On several occasions, I have been able to successfully do an 
In-Software-Service-Upgrade (ISSU) in a lab environment but then it fails 
to work in production.

I find it difficult to replicate the issue in a lab, since in production I 
am dealing with lots of routes as compared to a small lab.  Does anyone 
have any experience when the backup RE gets its new software, then 
reboots, but since it takes a long time to populate the routing kernel 
database on the newly upgraded RE that it appears to timeout?

I have seen behavior like this with upgrades moving from 10.x to a newer 
10.y and from 10.x to 11.y.

Clarke Morledge
College of William and Mary
Information Technology - Network Engineering
Jones Hall (Room 18)
Williamsburg VA 23187