Hi Ravenant,
Welcome to the J-Net community!!!
It's unfortunate that your SPC has failed on the secondary node. Please find the answer to your questions below:
My question is, are we losing anything? Is there any service degradation? If failover happens, will the secondary unit work as usual?
A:There is a possibility of service degradation. For instance, let's assume you have a huge load(sessions + bandwidth) on your primary node which is being handled by 2 SPC and NPC and if the failover happens then single SPC has to carry all the load which can hamper the performance.
Is this single NPC sharing both SPC? If yes, is single SPC running in combo mode able to handle this setup (10G throughput)?
A:For this question, I would suggest you look into the following forum link which has good discussion similar to the one which you've asked - https://forums.juniper.net/t5/SRX-Services-Gateway/SRX-SPC-and-NPC-Modules-and-Throughput-of-SRX-Firewall/td-p/196585
Also the problem is, SPC card for SRX3xxx is EOS and you cannot buy a new one.
A:I believe if you have a support contract you can reach out to JTAC for further proceedings.