- Daily
- 4.61 GB
- 30-day month
- 138.24 GB
- 365-day year
- 1,681.92 GB
Monthly and annual figures are generated volume before deletion. Retained volume assumes the same daily average throughout the retention period. File headers, metadata, backups and capacity allowance are excluded.
Use average recording activity
Enter the average number of calls being recorded during the entered hours, not the busiest instant of the day. Ten simultaneous recorded calls for eight hours create 80 call-hours. If recordings occur only on working days, average the workload across calendar days before entering it. Retention is also measured in calendar days.
A call is counted once when both directions are mixed into one mono file. Select two channels only when two channels are actually stored. Multiple recordings of the same transferred conversation can add further volume.
The file format controls storage
The negotiated SIP codec does not necessarily equal the recording format. A compressed call can be decoded and stored as uncompressed PCM. For PCM, bitrate is sample rate × bits per sample × channels. At 8,000 samples per second and 16 bits, one channel uses 128,000 bits per second before file headers.
Daily decimal GB = average recorded calls × hours × bitrate in kbit/s × channels × 1,000 × 3,600 ÷ 8 ÷ 1,000,000,000. The compressed 32 kbit/s choice is an assumption, not a guarantee for every encoder or file type.
Worked example and limits
The default 10 calls × 8 hours × 128 kbit/s mono produces 4.608 GB per day, 138.24 GB in a 30-day month and 1,681.92 GB over 365 identical days. A 90-day retention window holds 414.72 GB at steady state. Annual generated volume is not the same as retained volume.
Headers, indexes, filesystem allocation, replication and backups add storage. Variable bitrate, silence handling and actual call patterns can change the result. Measure representative files, then use the PBX storage planner to add voicemail, logs and capacity allowance.
Sources & applicability
Primary references for the technical details above. Operational examples and planning checklists are VoIP.info editorial guidance.