Extra info on continuous transaction storage
Hello,
From documentation:
Session Store Files vs. Performance Warehouse DB
The PWH DB stores time series from both: system monitoring (like CPU and memory usage) and timings from PurePaths. (one minute interval in highest resolution; data can be "aged" - granularity is diminished in medium (hour) and low (day) resolutions)
Live Sessions (RAM) are continuously persisted / streamed to disk if Continuous Transaction Store is enabled in Server settings > Storage. (ten second granularity)
Parts of such Live Sessions can be explicitly stored (right click the desired System Profile in Cockpit > Session Storage > Start / Stop Recording or > Store Session...), are visible in Cockpit > Session Storage and accessible via the dynaTrace Server.
Export Session additionally zips up the Stored Session files (.dts) and an Import Session from the file system makes it available in Cockpit > Offline > Local Sessions.
Stored Session files can contain a Memory Dump, Thread Dump, Sampling or full PurePath info. Stored PurePath Sessions include time series data too.
Question:
If i switch this off this setting off, will the data only be kept in memory? so after a reboot of the dynatrace server all data is lost?
With setting on the pure path data is saved on disk, Correct?
I ask this because my storage setting was 70GByte with continuous transaction storage on false, but dynatrace says that it uses 67GByte.
Is it possible to have more skipped / unrecorded purepath data if continuous transaction storage = false?
Thx
Best Answer
The option continuous transaction store (CTS) turned on uses the HDD as additional space to hold the pure paths. If this option is turned off
only the dT-Memory is used as a FIFO to hold the PPs. If CTS option is turned off the PP-data is lost after restarting the dT-Server. But keep in mint that also if CTS is on the additional available space is used as FIFO. So if new PPs hit the system (and no more space is available) the oldest PPs are removed.
Best, Herwig
Thx Herwig,
Hello,
we are on DT6.0 and we encountered again the problem (the 2nd time) that all our continous transaction store was lost when the dynatrace host was restarted (it is running on windows server 2008 r2 in a VM hosted on an ESX cluster).
as you can see there are just 16,92GB used since yesterdays data loss. before that the usage was close to 900GB and we were lucky.
please let me know about potential root causes. we've encountered this behaviour with DT5.6 as well.
thanks
Hi Edwin
If this is a reoccuring I suggest you open a support ticket. It should not happen that dynaTrace clears the data if there is plenty of room available
andi
hi Andi,
thank a lot, a support case has been raised in the meantime.
kr,
edwin
Hi there
We had a similar problem. The root cause was this:
We installed dT and moved the /sessions/stored directory (where the transaction store is hosted) and then only started dT for the first time. Because the default settings of the Storage Quota was much less that what was in the sessions/stored directory, dT cleared the oldest Transactions and we lost that information. Luckily we had a backup...
So the best way is to install dT, then start it and change the default settings to what it was on the old version (900 GB in your example), shutdown the server, then only copy the sessions/stored directory to the new installation and then start dT server again.
Not sure if you had a similar scenario, hope this helps.
Thanks
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