@RunLLM what is the ledger and journal size calculator

A ledger and journal size calculator is not explicitly defined as a tool or feature in the provided data sources. However, in the context of Apache BookKeeper (used by Pulsar and StreamNative), ledgers store persistent data and journals store transaction logs. The size of ledgers and journals is determined by configuration parameters such as

journalMaxSizeMB

for journals and the total size of ledger volumes for ledgers. These sizes can be monitored and managed, but there is no built-in "calculator" utility mentioned in the documentation or code references provided. To estimate or monitor these sizes, you typically review BookKeeper configuration and use monitoring tools or commands to check current usage. For example, you can use the

pulsarctl bookkeeper bookie list-disk-file

command to list journal and ledger files and their sizes on disk, but this is for inspection, not calculation or estimation in advance. Would you like more detail on how to monitor or configure these sizes in practice? Sources: - BookKeeper data management concepts - Pulsar architecture: managed ledgers and journals 👍 0 button 👎 0 button 💡 Hint: Mention @runllm in the thread for followups.

yes

Thank you for your response! Here’s how you can monitor and configure ledger and journal sizes in Apache Pulsar/BookKeeper (and by extension, StreamNative Platform): --- *1. Configuring Ledger and Journal Sizes* Journal Size - Parameter:

journalMaxSizeMB

- Description: Sets the maximum size (in MB) of a single journal file. When this size is reached, a new journal file is created. - Location:

bookkeeper.conf

- Example:

journalMaxSizeMB=2048

This sets each journal file to a maximum of 2GB. Ledger Size - Parameter:

entryLogFilePreAllocationSizeMB

and disk size for ledger directories - Description: Controls the pre-allocation size for entry log files (where ledger entries are stored). The total ledger size is determined by the available disk space in the ledger directories. - Location:

bookkeeper.conf

- Example:

entryLogFilePreAllocationSizeMB=2048

This pre-allocates 2GB for each new entry log file. --- *2. Monitoring Ledger and Journal Sizes* A. Using BookKeeper Shell You can use the BookKeeper shell commands to inspect the current state of ledgers and journals. - List all ledgers:

bin/bookkeeper shell listledgers

- Show disk usage:

bin/bookkeeper shell listdiskfiles

This will show you the sizes of journal and ledger files on disk. B. Using Metrics BookKeeper exposes metrics that can be scraped by Prometheus or viewed in Grafana: - `bookie_ledgers_count`: Number of ledgers stored in the bookie. - `bookie_entries_count`: Number of entries stored in the bookie. - `bookie_journal_JOURNAL_SYNC_count`: Number of journal fsync operations. - `bookie_write_cache_size`: Write cache size in bytes. More details: BookKeeper Metrics Reference C. File System Inspection You can also directly inspect the disk usage on the bookie hosts:

du -sh /path/to/bookkeeper/journal
du -sh /path/to/bookkeeper/ledgers