Hello, WAL active folder size calculation is correct, that is walSegmentSize * walSegment = 64 * 10 = 640Mb.
However, you may completely disregard estimations for WAL archive, as since latest 2.7 version there is a configuration property to limit WAL archive size in bytes, which is obviously more precise way to do so. Ticket for your reference: https://issues.apache.org/jira/browse/IGNITE-6552 Docs link: https://apacheignite.readme.io/docs/write-ahead-log#section-wal-archive Though there is the same link is on the under the hood page in WAL structure part, the ‘estimating disk space’ part has to be updated, thanks for your question! Best regards, Anton From: Venkata Bhagavatula Sent: Monday, August 26, 2019 4:59 PM To: [email protected] Subject: Ignite WAL and WAL archive size estimation Hi All, In the link: https://cwiki.apache.org/confluence/display/IGNITE/Ignite+Persistent+Store+-+under+the+hood#IgnitePersistentStore-underthehood-LocalCrashRecovery Following is mentioned about the Estimation: what is est. maximum data volume to be writen on 1 checkpoint? Is it the size of 1 wal segment or 1 checkpoint buffer size? Estimating disk space WAL Work maximum 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. Thanks n Regards, Chal
