How much disk do VICIdial recordings really use

The single fastest way to break Call recording on a VICIdial cluster is to let /var/spool/asterisk/monitor/ fill to 100%. New recordings stop writing with no warning to agents. Planning disk before you hit that wall is straightforward once you know the numbers.

Codec choice drives everything

VICIdial records using either the WAV format (Campaign Rec extension 8309) or GSM format (extension 8310). Both cover up to one hour per call. The Recording format (WAV/MP3) you choose is the biggest lever on storage size. WAV (uncompressed, 16-bit, 8 kHz mono) runs about 960 KB per minute. GSM (compressed) runs roughly 105 KB per minute — about a 9:1 ratio. The trade-off is that GSM sounds slightly flatter and requires a decode step when you play it back through a browser, while WAV plays natively almost everywhere.

Estimating your daily footprint

Start with three numbers: average call duration in minutes, total calls per day, and Recording retention window in days. Multiply them together with your per-minute file size, add 20% headroom, and that is your minimum disk requirement.

1. Average call duration (minutes) x per-minute size = size per call
2. Size per call x calls per day = daily intake
3. Daily intake x retention days = minimum disk
4. Add 20% operating headroom so the drive never hits 100%

A worked example: 50 agents, 100 calls per agent per day, 4-minute average call, WAV format, 90-day retention. That is 5,000 calls x 4 min x 960 KB = 18.3 GB per day, times 90 days = 1.65 TB before headroom. Switch to GSM and that same scenario drops to roughly 180 GB — a dramatic difference.

flowchart LR
  A[Call ends] --> B{Codec set in campaign}
  B -->|WAV 8309| C[~960 KB per minute]
  B -->|GSM 8310| D[~105 KB per minute]
  C --> E[Larger files - better quality]
  D --> F[Smaller files - compressed]
  E --> G[Size x calls x retention = total disk]
  F --> G

Stereo recordings double your numbers

If the campaign has Stereo recording enabled (Stereo Call Recordings set to BOTH_CHANNELS), each call produces two files: the standard mono recording and a stereo file. Multiply your storage estimate by two for campaigns using that feature. If you use Parallel Stereo Recordings as well, you may see three or more files per call.

The Recording Delay shortcut

The Recording delay campaign setting (available for ALLCALLS and ALLFORCE modes) delays the start of recording by a number of seconds you specify. Setting it to 10 seconds skips the answering machine and short-connect noise that pads file counts. On a busy predictive dialer this can meaningfully reduce the number of tiny recordings that still consume inode slots and inflate file counts even at near-zero size.

Monitoring before you run out

Add a cron-based disk alert that fires at 80% usage on the monitor partition. At 85% move the offload cron to run every hour instead of nightly. At 90% pause non-essential recording campaigns until capacity is restored. Reacting at 80% gives you time to offload or expand before calls are affected.

**Heads up:** The Asterisk process that writes recordings (MixMonitor) will silently fail to open new files when the filesystem is full. Agents see no error; recordings simply do not exist. A disk-full condition looks identical to a MixMonitor misconfiguration from the outside.

Offloading to keep hot-tier lean

Keep only 30–90 days of recordings on local disk and rsync the rest to a NAS, S3-compatible store, or a cold archive server. This is the standard VICIdial recording offload pattern. Your vicidial_recordings table rows remain intact so searches work; retrieval of older files needs a fetch step from the archive location.

For the full recording setup picture, start with VICIdial call recording explained. For codec decision details, see how to record in GSM vs WAV. Want managed hosting where storage scaling is handled for you? See VICIfast pricing.