Apologies for being a bit blunt here, but it doesn't sound like that's what they are going to do. It sounds very much to me as though the boss has decided you're a liability, can't be trusted with the real work and just wants somebody to do the menial jobs and take the flack when needed.
Thats not to say that you actually are that, you've just fallen out of favour with the boss and his opinion is less of you than you deserve. Don't be scared to leave, he only way you are going to get any happiness is by changing jobs. Your boss is content to have you for a mug and your colleagues are quite happy to lord it up and leave all the boring stuff to you.
I wouldn't expect that pay rise and counter offer. I'd just focus on finding that new start.
It would appear that way. But I can tell you why this is so. It's historical.
Before I started there was just two of them, and they couldn't cope on their own and needed a run around. Someone to go to the other sites to do the menial stuff whilst they could get on with the actual IT.
So they hired me. At the time I had zero experience. It was my first job. So was just happy to have a job. At the time I was going round and round. I was either too qualified (masters degree) or didn't have enough experience.
Over the years my role took on more responsibility as I gained experience and knowledge. About 3-4 years in to my 8 years at this company the other Linux guy started experiencing difficulties with a sick farther. He disappeared for about 6 months. But was all over the place for at least 2 years. Turning up maybe 1-2 days a week. Depressed, going for 3-4 hour lunch breaks etc... So they hired another Linux guy to help out my manager.
This was the only reason why the team grew to four. Fast forward, the other guy is back and more stable, but during this time, the guy they hired is lazy and according to him was only hired to do Linux not technical support, so basically got annoyed with the technical support found another job, quit then accepted an offer with the current company at a higher wage packet. (And must have a verbal agreement with my manager that he doesn't have to do technical support because he gets away with murder)
So this is the reason why all the menial stuff is given to me. It's a mixture of historical and the other two thinking it's not their job/lazy.
Even my manager does the technical support but the other two get away with being lazy.
Even the people I support have complained that the other two are lazy and rude!
With out me, they wont have the luxury of laziness, as the new guy if junior wont hit the ground running and if they hire someone of higher technical ability to me he equally want wont to do aspects of my job so it will have to be shared out, which is going to be painful for the lazy people I work with.
I know for a fact one of the guys I mentioned (who says it's not his role to do technical support - it is) will quit shortly after I go because with out me will have to suddenly do some work!
So yes, I believe they will offer me a counter offer to stay. My manager has indicated to me numerous times 'my job is important'. Even when they verbally gave me my pay rise last week, he asked me if that was enough for me to stop looking....
---
But I'm not really looking at this from a money perspective. I'm looking at it from a skills/experience perspective. I know for me to be earning twice my wage which they are, I too need to be getting experience with what they do. And in my current job, not only does my manager not give me anything to get my hands dirty, but I dont have time either with all the support rubbish I have to deal with.
The other reason is the partition of the department. As mentioned above, the other two historically are hired to do the infrastructure stuff and me I was just a run around. So if they give me more interesting stuff to do I'm sort of taking work from them and they wont do my work, so in the end I lose out again as I fall behind with all the support crap.
What they should be doing is telling the other two they have to share more my role and theirs so all three of us can share the workload and I can do some more interesting things. But I know at least one of them will NOT be bothered. He has a few menial stuff to do himself and when he gets chased about it, he just says 'I'm busy coding', when in reality he finds plenty of time for cigarettes and facebook and nonsense on his phone.
Also this same guy, sometimes doesn't even bother to open up his email and definitely doesn't look at the ticket system.