Performance / "Thrashing"

[J.Pluta]

Performance / "Thrashing"

To be honest, Doug, I don't ever use ASPs. I have heard of them being used for specific purposes like separating journal receivers from the files they are journaling, but I've never needed them. But in general I think you're right on with your assessment of both memory pools and ASPs. Joe As an aside, if you ARE using WebSphere (or any other Java intensive application), I highly recommend a separate private memory pool for it. The way the JVM handles memory is not compatible with the way OS/400 usually handles memory, and combining the two management methods often leads to performance problems.

[Guest.Visitor]

Performance / "Thrashing"

Doug Englander wrote: > Auxilary Storage Pools are basically the same concept, but apply to > disk file storage allocation. ASPs allow me to use the whole disk > storage as one logical unit, or gives me the ability to tell the > system what physical disk unit(s) comprise a logical disk unit. The > allocation of specific objects to specific ASPs is made at the > library level (I think). Basically this is all correct. There are certain exceptions like an overflowing ASP, but that's a rare occurance that would need to be remedied. Allocation of folders in the IFS to an ASP is done at the Link level IIRC. Bill

[Guest.Visitor]

Performance / "Thrashing"

Thank you Joe and Bill for your replies. I appreciate your time. At this point, I have 3 questions: 1. What is the advantage or disadvantage of having everything other than *MACHINE, *INTERACT, and *SPOOL memory be lumped together into *BASE, as compared to breaking what would be *BASE (the leftover memory) up into other pools of various sizes? 2. What is the advantage or disadvantage of having one subsystem have multiple pool definitions as listed on the DSPSBSD command? Why would I need to have the routing entries in the subsystem description point to multiple pools? 3. Is there any rules or guidelines that should be used to determine the defined size of a pool as well as its activity level? Thank you!! Doug.

[J.Pluta]

Performance / "Thrashing"

You're asking for a "one size fits all" answer to a question which requires is completely dependent on your system. In general, though, you create multiple pools only to separate workloads. For example, carving a small amount of memory and dedicating it to your printers makes sure that one doesn't somehow spin out of control and take down the rest of your system. As I said, separating Java workload from other work is a recommended practice. Other than that, I can only think of two situations off the top of my head where multiple pools provide a real benefit. One might be if you have a specific memory pool for "pinning" objects. The SETOBJACC command allows you to pin an object into RAM, making access virtually instantaneous at the cost of memory. However, having that memory swapped to disk sort of defeats the purpose, so you might create a small pool of just the right size to hold your pinned objects. The other would be if you have low priority jobs that can be swapped out. These jobs would be put in a smaller pool with less memory, and other higher priority jobs would be in a different pool. You don't need this, though, if you smiply give the higher priority jobs a higher CPU priority; they will force other jobs to wait anyway. How do these pertain to your situation? Given the 7000 active jobs, I'm still not sure what you need; I'd have to fall back to the standard answer "it depends". Joe

[Guest.Visitor]

Performance / "Thrashing"

Our system is very slow and has consistently high and steady CPU usage throughout the day. I suspect there is too much batch running at once. Attached is what our WRKSYSSTS screen shows. Can anyone tell me in a nutshell what the problem might be, and what a quick solution might be? Thank you!

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Code

[Guest.Visitor]

Performance / "Thrashing"

Joe and others, At this point, what I need is research and documentation time (ha ha). Anyway, I REALLY appreciate your responses as well as all others who contributed to this forum. I at least now have a better high level understanding on hall all of these settings work. Thank you, Doug.