My Connect server is at 256M with 768M swap ( dunno how it landed there ) -
I usually have around 60 connections through it and expect to see up to 500
or so.
Nothing like your slow down yet - though it sounds like our typical luck.
Last time I saw anything similar on DB2 for z/OS was when I didn't have the
WLM goals set correctly for the address space.
I do have the connect server connecting to the z/os db2 via hypersocket -
very fast response with that.
Tom Duerbusch
<duerbus...@stlou
iscity.com> To
Sent by: Linux on [email protected]
390 Port cc
<[email protected]
IST.EDU> Subject
Re: DB2 on z/VM & SuSE 10.2 "box"
sizing - starter values ?
05/19/2009 02:11
PM
Please respond to
Linux on 390 Port
<[email protected]
IST.EDU>
We are going into production, tomorrow, with DB2 Connect Server V9.5
fixpack 2. A Cashier system, with about 8 users.
I'm on 160 MB virtual, 1 3390-9 drive, two vdisk swap files (about 10,000
4K swap pages used over 3 weeks).
This is on a z/890, with the IFL about 20% busy. And no VM paging.
Only problem we have had, and can't seem to shoot, yet, is we are using
stored procedures on DB2/VSE. About 1 in 10 transactions, has a 20-30
second startup time. Not the first, not the last. Just blind sided.
Every box in the transaction path, was not having a CPU problem, an IO
problem or a Paging problem, when we had poor response time.
Did you have that, and did you solve it?
On the DB2 side, my guess is you have too much virtual storage defined.
You should have automatic memory management enabled (by default). So
scaling back will also scale back the DB2 cache. Check the hit ratio. But
I wouldn't try to keep the hit ratio at the same level as the other
platforms. If you are on ficon, you have one hell of a kick ass I/O
subsystem. Trade some memory for I/O, within reason. That gives you more
memory for more servers, until you hit CPU limitations.
BTW, my test UDB servers are 512 MB each. Only 2 3390-9 packs for data.
Yep, the first time thru, the application ends up loading DB2 cache, and
then the queries fly. Testing doesn't need a lot of cache. I don't have
Websphere, so I can't consider it's memory loads.
Tom Duerbusch
THD Consulting
>>> <[email protected]> 5/19/2009 11:13 AM >>>
I'm finally in the process of firing up some "boxes" under VM to replace
some aging AIX critters and I could use some advise as to real memory and
swap allocations for these new guys.
1st victim was a DB2 connect enterprise unlimited server - cut it to
production 2 weeks ago and everything is good. 246900k of memory and 3G of
swap, so far, so good except for a small issue with java versioning v1.5 on
new box, v1.3 on oldest client app - but that is a java issue that would
show up on any platform with the new version.
2nd victim is a DB2 ESE and WebSphere MQ server - can't even fire up the
tools database because the bufferpools don't have enough memory. This is
where the advise is needed since the IBM docs don't have a recommended
starting point for the z/VM environment ( DB2 9.5 fixpack 3b) and I really
don't want to scarf all of the vm resources for this machine when the grand
plan ( insert evil laugh here ) is to put as many AIX and intel linux onto
this platform (Z) as we can and still maintain decent performance.
Current AIX box is a 2-way power3 box with 16G of memory - low utilization
in a development environment.
3rd victim is a WebSphere AppServer box - 6-way power4 box with 16G memory.
Low to moderate utilization in a development environment with a second
instance of WAS for background production use ( the moderate utilization
part - when it is active ).
Current VM lpar has 2 IFL, 9G cstor, 3G estor, z/VM 5.3 and SuSE 10.2
guests
Thanks,
Bruce
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