Need help: Cachesize parameter

Hi,

Environment: TS 6.5 SP1
OS: MS Win 2003
4 CPU
8 GB Ram

I need some coaching about the iw.cfg, section [iwserver], parameter "cachesize":
Admin guide says:

cachesize=45000

Minimum cache size is 1000; maximum is 400,000 entries. Each cache line takes a
maximum of 1KB of physical memory.
...
Note: The value of cachesize is not the amount of memory that is used, but the number
of objects kept in the cache.

I read out, that the cachesize parameter can set up with a value between 1000 and 400,000.
But what does the sentence "Each cache line takes a maximum of 1KB of physical memory" mean,
especially: what is a cache line?
If I have a cachesize value of 45,000, do I have 45,000 cache lines with 1KB each?

Then there's the given note:
"value of cachesize is the number of objects kept in the cache"
If I have a cachesize value of 45,000, my cache can contain 45,000 objects (files or what?)?
But what's with the memory amount of 45,000 objects?

Perhaps someone could bring some light into this...

Regards
Stefan

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Comments

stefanmaier

Nobody?
Doesn't anybody know the meaning of "cachesize"?
Any IWOV guys?

mstradling

Does it really matter?

The normal approach to tuning TeamSite is the suck-it-and-see method.

For a start, are you having any performance issues with the default cache size?

If you do want/need to change it, take a look at KB51169.

Basically increase cache size if:
1. The output iwstat -c shows ~90% of total cache slots in use. The cache is fully populated.
2. The system has sufficient physical memory to accommodate larger iwserver process.
3. There is significant cache turnover.

Decrease if:
1. iwserver process approaching or exceeding 2Gb.
2. iwserver process getting pushed out to swap. This would mean more disk activity which can slow down the performance.

stefanmaier

Hi,
thanks for that KB article.
Background ist, that we reached the 2GB limit two times. Consequence was a segmentation fault of the iwserver process.
So a decreasing of the cachesize seems to be required.
Question is: how much should we decrease?
To specify a lower cachesize, which is not to low, it would be good to know, what's the meaning of this parameter...