Recovery Monkey: Musings on backups, storage, tuning and more

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Thu
20
Dec '07

Ate at Delmonico’s in NYC

I was helping out a customer with some backup issues in the Wall street area and they happened to be literally across the street from Delmonico’s.

At the end of a particularly long day I thought I’d reward myself with a nice steak, and the proximity to the steakhouse made it hard to resist.

Delmonico’s is one of those places that have been around forever. Bit stuffy inside, I didn’t opt for the wet-aged Delmonico cut but instead went for the T-Bone (dry-aged on-premises). I also had a rather excellent salad with roasted tomatoes, herbs and mozzarella.

This is not going to be one of those inspired entries – the steak just wasn’t that good. It was undercooked, underseasoned and just lacked flavor. I probably should have gone for the house’s signature cut (the famous Delmonico cut) but any decent steakhouse should have no problems making a proper T-Bone…

Maybe I’ll give it another chance. Prolly not.

D

Sun
9
Dec '07

We need more wizards!

No, I don’t mean Gandalf, I mean the software kind. And before I’m accused of being Gates’ live-in cabana boy (it’s all baseless rumors), let me clarify.

It’s a known fact that most OSes need tuning (sometimes significant) to perform well with heavy-duty applications (I’m not talking about your home web server, I’m talking about Exchange, SAP, Oracle, IIS, Apache etc. in large deployments. I acknowledge the fact that most OSes, out of the box, will work OK for anything small).

Most frequently the application documentation will have some kind of tuning guidelines telling you approximately what to do in each OS. The installer sometimes will apply some tunings for you after asking for your permission. Often, the suggested settings are woefully inadequate for truly large implementations, as with NetBackup (the Veritas-suggested tunings work for smaller environments but I have some magical kernel tunings as posted before that make it truly fly when the ridiculous is asked of it – and the difference in the parameters between my config and what Veritas suggests is huge. Oh, and some of my parameters are way smaller than what Veritas recommends. And I won’t call them Symantec, Veritas is a way cooler name anyway, look it up in a Latin-English dictionary).

Frequently, some tunings are so common that I don’t even know why they’re not in the default configuration in certain OSes. Different conversation.

The problem is, there are experts that DO know how to set up and tune the systems properly, but said experts are rarely the admins that install and administer the thing. Usually, a fair portion of those experts do work at the companies that make the OSes and apps.

The elitist among us might say, “tough, the lowly admins need to learn all this stuff, otherwise they’re not worth what they’re paid”. To which I respond with the following points:

  • Not everyone has the time to learn the arcana of several OSes and applications, learning most of the important features is complicated enough and some shops are truly short-staffed
  • The über-experts themselves don’t know it all: They may know how to perfectly set up Exchange but wouldn’t know how to do the same thing with Oracle, how can the basic admins be expected to have such multi-discipline expertise?
  • I firmly believe in the simplicity of the appliance computing model
  • We all have more important things to do (like taking care of the big picture) than constantly worrying about minutiae
  • The people that complain that the admins should be more intelligent are typically the people that actually enjoy dealing with the apocryphal, their jobs are secure anyway
  • There’s money to be made in the simplification of IT – look at Microsoft, EMC/VMware and NetApp. People like simplicity and are willing to pay for it.

Of course, many larger companies will opt for professional services to do the job, but the quality of people just varies dramatically. Just because you’re getting an expensive Veritas PS guy doesn’t mean that

  1. He knows what the hell he’s doing beyond what’s in the installation manual (you know who you are!) and (less significantly)
  2. Is even a Veritas employee, despite his badge (most vendors subcontract smaller companies).

At the moment, most OSes just apply generic formulas based on memory and/or number of CPUs, though somehow do not take into account CPU speed and load, and, indeed, the ancient formulas are a pain with today’s very large memory systems (usually you have to limit some tunables in large-memory HP-UX and Solaris boxes, otherwise some parameters get out of control).

I understand that making OSes truly self-tuning is not here yet, nor will it be for a while (64-bitness has taken away some of the pain though, at least in Windows). In the interim, there are better ways to approach the problem. My suggestion: Modernize the formulas that build the tunables and use simple AI techniques like Expert Systems. At installation time, benchmark the hardware and ask the user what will the server be running? OK, so if the answer is a web server, under what conditions? How many users? And so on. Admins are far more likely to know the answers to those questions than “how many open file handles do you think you’ll need?”

Based on the answers and the benchmark results, the system should either tell you what you want is possible, or bitch.

If the box is to be serving double-duty (or quintuple, in some cases), the wizard should check and see if the tunings will conflict and, if not, tune the whole box so that it can accommodate all the applications.

If you’re creating a filesystem, what will the intended use be? The defaults for almost all filesystems are wrong! One size fits only the people that have that size. The problem is that, once you’ve put in several TB on filesystems someone built with the default parameters, changing them is almost impossible: you have to take a backup, destroy the filesystems, rebuild them then restore the data. Which could have been avoided if, say, maybe not the OS but at least Oracle had the smarts to query the FS and figure out it’s using insufficient log and block sizes and that performance will suck. At which point it should puke and tell you “sorry, this is sub-optimal, either do such-and-such to fix it or continue anyway at your peril”. But of course you’re using raw disks for Oracle, right? Right?

Or take the example of Logical Volume Managers. They are cool, yes. They can work great. They will also let you do insane things such as create multiple LVs and stripe them, even if they’re on the same physical disk! The checks that should have been performed are so ridiculously simple it boggles the mind.

HP kinda started doing something like this a while ago – look at the templates in SAM, you can apply 2-3 different (useless) templates based on what the box will be doing that will affect a few tunables. HP-UX is guilty of needing the most tuning of any current OS I can think of, BTW (It also pays great dividends if you know what you’re doing, I took a Superdome to 2x the I/O performance once, felt proud but it took a lot of effort and research that could have been avoided).

Seems like the intelligence that would make our lives easier is like the proverbial hot potato: always someone else’s problem.

I know it’s a tall order: the whole solution would rely on much deeper interoperability between the various components than we’re used to. But I think the end result would be worth it.

In the meantime, if you have to do it all yourself, at least use common sense and have some golden OS builds that are each good for a different use, then just replicate them as needed.

Anyway, all this is aggravating my hemorrhoids (I call them The Grapes of Wrath), better stop now.

D

 

Fri
7
Dec '07

(Very) Preliminary Windows Server 2008 impressions and Vista Multimedia Performance under battery power

Out of curiosity, I very briefly tried the new Server 2008 Release Candidate (freely available from Microsoft). I’ve been using Vista 64-bit since I need to see all the memory in my machine and, while it works mostly OK, there are some low-level scheduling issues with it – for instance, sound is really choppy on battery power, no matter what I do with the power settings, so I can’t use the thing to watch a DVD or listen to music on the plane. Many others seem to be having the same issues, despite the funky Multimedia Class Scheduler nonsense that Microsoft put in the OS that makes networking slower (great info here), even though older incarnations were not suffering from media playback issues under load. And no, if I disable the Multimedia Scheduler it does NOT work better, it actually gets worse, which means that the service is there to fix some other kludge-y issue Microsoft introduced with the scheduler or something like excessive power throttling of certain devices.

But, as usual, I digress. This is about Server 2008. What’s noteworthy is that Vista SP1 inherits the exact same kernel as Server 2008.

This will be a short entry, there are others online talking more about 2008. What I noticed:

  1. It’s light for a Windows OS. There’s no excessive bloat guys, the thing takes about 300MB of RAM with the default install, and more can be saved by trimming unnecessary services (of which there are very few).
  2. It’s fast. Under preliminary benchmarking, even the RC code (that probably has some features missing and extra debugging code) seems about as fast as 2003 after SP2 (unlike others that have been releasing benchmarks of, say, Vista SP1 in it’s pre-release form, I’d rather wait until the final code is out).
  3. Seems to work with most Vista drivers so, if you want to turn it into a workstation, you can. You can also install the Vista GUI if you’re so inclined with no adverse effects (aside from the ones that come with the Vista UI that is). Runs very smooth.
  4. Application compatibility is similar to that of Server 2003.
  5. The OS does NOT suffer from the same issues as Vista regarding media playback (I made sure I installed the Power Management driver and selected the same kind of PM scheme as Vista). Maybe a good omen come Vista SP1? We shall see.

The new management interfaces are nicely laid out, and selecting Roles for the server and adding or removing features as needed is very simple. It feels more like a well-integrated 2003 R3 rather than Vista.

I didn’t get to play with the new virtualization, it doesn’t seem to be in the RC code (though, reading some documentation, it seems as if it will have VMotion-like capabilities, which I will believe when I see).

UPDATE: 12/17/07

There is no more Vista multimedia performance issue on 2 separate computers. Some patches just released by Microsoft removed the issue (plus the issue of the mouse cursor stuttering). Interestingly, the patches had no mention of fixing said issues. I thought it was a fluke but having seen this fixed on 2 different boxes (one 32-bit, one 64) I don’t think it is.

For the Vista detractors: I’d advise everyone to wait until SP1 – as with most Microsoft releases. It’s no different. They’re actually getting better, NT4 was unusable until SP3 at least… given the unreal amount of code in the system, I’m surprised it runs this well. They really need to slim it down. Supposedly, Windows 7 will be slimmer (http://apcmag.com/7668/beyond_vista_windows_7_what_we_know_so_far). However, it mostly targets the kernel and it was never the Windows kernel that was the issue (it’s actually surprisingly decent), it’s all the crud around it.

D