Without making enemies on the SAN team, how can I reassure myself and the application developers that our SQL servers aren't suffering from poorly configured storage? Just use perfmon stats? Other benchmarks like sqlio?
In short, there probably isn't a way to be truly sure. What I would say (I am a SAN admin), is that if your applications are performing up to your expectations, don't worry about it. If you start to see performance issues that you believe could be related to SAN/Disk IO performance, then it might be wise to inquire. I do not use much HP storage like you do, but in the IBM/NetApp world I can say from experience that there aren't many options which would allow you to configure it "poorly". Most enterprise storage these days takes a lot of the guesswork out of building raid arrays, and doesn't really let you do it wrong. Unless they are mixing drive speeds and capacities within the same raid groups you can rest-assured in most cases that your disk is performing fine.
If I load test on these SAN drives, does that really give me a reliable, repeatable measure of what I will see when we go live? (assuming that the SAN software might "dynamically configure" differently at different points in time.)
Load testing should be plenty reliable. Just keep in mind that when you are load testing one box, that being on a shared SAN/Disk Array that its performance can (and will) be affected by other systems using the same storage.
Does heavy IO in one part of the SAN (say the Exchange server) impact my SQL servers? (assuming they aren't giving dedicated disks to each server, which I've been told they are not)
It can. It is not all about the disks, or which disks, the servers are on. All of the data is being served up via a disk controller, and then a SAN switch. The performance you will see greatly depends on how the disk controller is connected to is corresponding disk shelves, and the corresponding SAN. If the entire array connects to the backbone SAN on one single strand of 4gbps fiber, then clearly the performance will be impacted. If the array is connected across two redundant SAN's which are load balanced, using trunked links, then it would impossible for exchange alone to suck up too much bandwidth. Another thing which needs to be considered is how many IO/sec the array is capable of. As long as the array and the SAN it is connected to are scaled correctly, heavy IO in other parts of the SAN environment should not impact your SQL performance.
Would requesting separating logical drives for different functions logical drives (data vs log vs tempdb) help here? Would the SAN see the different IO activity on these and optimally configure them differently?
That is probably a matter of preference, and also greatly depends on how your storage admins configure it. They could give you three LUNs in the same array or volume, in which case its all the same anyway. If they gave you individual LUNs on different arrays, in different volumes (physically different disks), then it might be worth it for you to separate them.
We're in a bit of a space crunch right now. Application teams being told to trim data archives, etc. Would space concerns cause the SAN team to make different decisions on how they configure internal storage (RAID levels, etc) that could impact my server's performance?
I don't imagine your storage admin would change the raid level in order to free up space. If he would, then he should probably be fired. Space concerns can lead things to be configured differently, but not normally in a performance-impacting way. They might just become a little more tight about how much space they give you. They might enable features such as data de-duplication (if the array supports it) which can hinder the performance of the array while the process runs, but not around the clock.
Best Answer
If it's a unique problem, how can you measure whether the problem lay in the person or the problem?
You should be documenting everything that would be required to get your department running if half your people are killed/fired/etc...if you needed to rebuild the department with new admins, they should be able to get things running again at a new location with your documentation.
In practice...hee! Yeah, right. You're lucky if the docs are kept up to date if they're even created in most places.
If you're managing the monster tasks perhaps you need to just meet up with your admins and ask how things are going and what's been tried. If in this three weeks he's been tasked with just this problem and it's not getting solved, is it because he's not working on it? What has he tried to rectify the issue?
You can't micromanage the issue or he'll probably start fighting you on it. The sysadmins need enough freedom to work without feeling like he's being scrutinized every step. But if the project or task is really far behind, then you have a legitimate concern. Find out from him if there's something he needs in order to get the job done, or what the problem is that he is having difficulty overcoming.
Good book: Managing Humans by Michael Lopp.
Performance should be based on how well IT issues are addressed to meet the needs of users, along with maintenance of the servers and infrastructure issues. You can't possibly reduce the issue down to "solving X issues a day" or "writing X lines of code" to measure each employee.
Maybe you can get input from others on the team to get some feedback on how each other is doing or what major needs are. Good techies want to work with good techies. They don't want to work with people that are "happy and nice" but incompetent. They'll work with a grumpy curmudgeon who hates being in the room with them if it means that everything works well and the curmudgeon knows his stuff.