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paging out

Michael Schulte zur Sur
Honored Contributor

paging out

Hi,

I have an 4100 with 4 cpus and 4gb and roughly 150 with an interactive customs software. The database is oracle and it running not in shared mode. My problem is, that the system is slow and paging. Attached you can see the settings for vm. If ucb-max-percentage is too high, could it be, that the system is beginning paging too early? The system is running still 4.0F

thanks for any help

Michael

vm:
ubc-minpercent = 10
ubc-maxpercent = 60
ubc-borrowpercent = 20
ubc-maxdirtywrites = 5
vm-max-wrpgio-kluster = 32768
vm-max-rdpgio-kluster = 16384
vm-cowfaults = 4
vm-mapentries = 16384
vm-maxvas = 1073741824
vm-maxwire = 16777216
vm-heappercent = 7
vm-vpagemax = 131072
vm-segmentation = 1
vm-ubcpagesteal = 24
vm-ubcdirtypercent = 10
vm-ubcseqstartpercent = 20
vm-ubcseqpercent = 10
vm-csubmapsize = 1048576
vm-ubcbuffers = 256
vm-syncswapbuffers = 128
vm-asyncswapbuffers = 4
vm-clustermap = 1048576
vm-clustersize = 65536
vm-zone_size = 0
vm-kentry_zone_size = 16777216
vm-syswiredpercent = 80
vm-inswappedmin = 1
vm-page-free-target = 1536
vm-page-free-swap = 778
vm-page-free-hardswap = 24576
vm-page-free-min = 20
vm-page-free-reserved = 10
vm-page-free-optimal = 778
vm-page-prewrite-target = 3072
dump-user-pte-pages = 0
kernel-stack-guard-pages = 1
vm-min-kernel-address = 18446744065119617024
malloc-percpu-cache = 1
vm-aggressive-swap = 0
vm_page_color_private = 0
vm-map-index-count = 64
vm-map-index-rebalance = 128
vm-map-index-enabled = 1
vm-map-index-hiwat = 4
vm-map-index-lowat = 2
new-wire-method = 0
vm-segment-cache-max = 50
vm-page-lock-count = 64
gh-chunks = 0
gh-min-seg-size = 8388608
gh-fail-if-no-mem = 1
private-text = 0
private-cache-percent = 0


5 REPLIES
Pedro Albuquerque
Frequent Advisor

Re: paging out

Hello, the value that are advised by Oracle, for VM are:

ubc_minpercent=5
ubc_maxpercent=10
ubc_borrowpercent=9

vm_ubcseqstartpercent=50
vm-swap-eager=0

Try this values and you probably will obtain a better performance.
Michael Schulte zur Sur
Honored Contributor

Re: paging out

Hi Pedro,

good idea. I was already wondering, why top showed so little memory used and so much in swap. But where did you get this advice. I couldn??t find it in metalink.

Michael
Michael Schulte zur Sur
Honored Contributor

Re: paging out

Hi Pedro,

I tried your values, but it didn??t work out.
We had to return to the old values.
What puzzles me, is that Oracle suggests in the documentation for real application cluster suggests even 70% percent for ubc-maxpercent.

But thanks anyway.

Michael

Blake Roberts
Frequent Advisor

Re: paging out

Michael,

I noticed that your vm-page-free-hardswap number is fairly high. Try lowering it down to 16384 to see if it helps. Also, if you run a normal "sys_check" on the system, it usually gives recommendations for kernel parameters, especially if there is one or more set improperly.

Regards,
--Blake Roberts
Michael Schulte zur Sur
Honored Contributor

Re: paging out

Hi Blake,

vm-page-free-hardswap

is calculated by other values according to memory, so since I have 4gb, it might seem large.

Michael