[ 
https://issues.apache.org/jira/browse/IGNITE-7730?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Dmitriy Pavlov updated IGNITE-7730:
-----------------------------------
    Fix Version/s:     (was: 2.5)
                   2.6

> Improve WAL history size documentation
> --------------------------------------
>
>                 Key: IGNITE-7730
>                 URL: https://issues.apache.org/jira/browse/IGNITE-7730
>             Project: Ignite
>          Issue Type: Task
>          Components: documentation
>    Affects Versions: 2.1
>            Reporter: Dmitriy Pavlov
>            Assignee: Denis Magda
>            Priority: Major
>             Fix For: 2.6
>
>
> Until IGNITE-6552 is not implemented, we have only ability to configure WAL 
> hist. size in checkpoints.
> It is needed to improve description for this parameter.
> I've added draft notes to wiki 
> https://cwiki.apache.org/confluence/display/IGNITE/Ignite+Persistent+Store+-+under+the+hood#IgnitePersistentStore-underthehood-Estimatingdiskspace
> about ways how wer can estimate WAL sizes without exact bytes/time 
> specification:
> {panel}
> WAL Work max used size: walSegmentSize * walSegments = 640Mb (default)
> in case Default WAL mode - this size is used always,
> in case other modes best case is 1 segment * walSegmentSize
> WAL Work+WAL Archive max size may be estimated by
> 1. average load or
> 2. by maximum size.
> 1st way is applicable if checkpoints are triggered mostly by timer trigger. 
> Wal size = 2*Average load(bytes/sec) * trigger interval (sec) * walHistSize 
> (number of checkpoints)
> Where 2 multiplier coming from physical & logical WAL Records.
> 2nd way: Checkpoint is triggered by segments max dirty pages percent. Use 
> persisted data regions max sizes:
> sum(Max configured DataRegionConfiguration.maxSize) * 75% - est. maximum data 
> volume to be writen on 1 checkpoint.
> Overall WAL size (before archiving) = 2* est. data volume * walHistSize = 1,5 
> * sum(DataRegionConfiguration.maxSize) * walHistSize 
> Note applying WAL compressor may significiantly reduce archive size.
> {panel}
> One more note from [~ivan.glukos] on dev.list we need to include. It is 
> answer to question how user can determine if segment from archive folder can 
> be safely removed:
> {quote}
> By the way: WAL compression is already implemented that way. If there
> are any ".zip" segments in archive dir, they are free to delete.
> This can be a safe workaround for users who experience lack of free
> space - just delete compressed segments. We should mention it in
> documentation for 2.4 release.
> {quote}



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

Reply via email to