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Artem Budnikov commented on IGNITE-7730: ---------------------------------------- [~dpavlov] please provide information I asked you about by email. > 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: Dmitriy Pavlov > Priority: Major > Fix For: 2.7 > > > 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)