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"Server cache limit - how to resolve?"

genesius_jarom1
Organizer

One simple way to answer this, increase the cache limit.

But there must be other ways to better handle this issue.

Here are 3 postings on this issue:

https://answers.dynatrace.com/questions/118885/ser...

https://answers.dynatrace.com/content/idea/129080/...

https://answers.dynatrace.com/questions/124034/ser...

How do you resolve the "Server cache limit exceeded" problem?

Thanks and God bless,

Genesius

7 REPLIES 7

raffaele_talari
Inactive

Hi Genesius,

have you already checked this page?

https://community.dynatrace.com/community/pages/vi...

It reports a checklist of solutions to the exceeded Server cache limit situation.

Hope it helps.

Ciao, Raffaele

Thanks @Raffaele Talarico,

The link brings me somewhere else.

https://community.dynatrace.com/community/display/...

God bless,

Genesius

Genesius don't know why the link didn't work.. Please try this one:

https://community.dynatrace.com/community/x/UAggD

If it won't work again probably you don't have enough rights to see that page..

Let's see.

Raffaele

@Raffaele Talarico,

Same.

Thanks and God bless,

Genesius

adam_piotrowicz
Dynatrace Pro
Dynatrace Pro


Genesius,


The general answer is:


If CAS performance is good you can keep on increasing it. If it's not, then inspect configuration in the following aspects:



  • AMD configuration resulting in higher number of operations,

  • amount of days stored in DB,

  • URL Aging settings,

  • being on CAS < 12.3.7


By saying CAS performance is good I mean that:



  • processing of data files is not exceeding monitoring interval,

  • you're not pushing the storage limits on DB server,

  • Memory resident on http://CAS/modulestatus is > 95%,

  • overall CAS performance looks to be fine


Remember that default server cache limit has been set by Dev/ProdMgmt and is not applying to all installations. If you see the error message, then run the following script:


select * from
(
select top 10 'Software
Service' attr, A.name, count(distinct url_id) "operations" ,
count(*) sessions from
rtmsession S (nolock)
join rtmapplications A (nolock) on A.row_id=S.appl
group by A.name
order by 3 desc
) SERVICES
union all
select * from
(
select top 10 'Server'
attr, SRV.dns_name, count(distinct S.url_id)
"operations", count(*) sessions from delta.rtmsession S (nolock)
join rtmserver SRV (nolock) on SRV.row_id=S.svr_id
group by SRV.dns_name
order by 3 desc
) SERVERS<br>

to find top SSes that gives you most operations, and inspect them in DMI.

Ask yourself a question if you really need so many operations.

Investigate if operations contain unique tokens that are multiplying it.

Please also be aware that in "Capacity Settings Editor" screen there is an option "Ignore capability recommendations". When it is set to "OFF", one cannot freely increase the limits. In this mode limits are increased in steps. System calculate how much the value will be increased each day.

For example, if the current limit value is set to 1000. When limit is to be increased up to 10000, it will be done in steps by 500 each day. It will take 18 days to finally reach the desired 10000.

Decreasing the limits can be done instantly.

When the option "Ignore capability recommendations" is set to ON all limits can be changed instantly.

raffaele_talari
Inactive

Here we go @Genesius Jaromsky.. 🙂

Ciao, Raffaele