21. Glossary

3-2-1-1-0. Three copies, two media types, one off-site, one immutable or air-gapped, zero errors on restore verification. 3x free egress. B2 allowance: monthly egress up to 3x average stored data (byte-hour average) is free; beyond is $0.01/GB. AFR. Annualized failure rate of hard drives. Backblaze publishes it quarterly in Drive Stats (Q2 2026: 1.73 percent). App key (application key). B2 credential: keyID + applicationKey. Master or standard. Standard keys scope bucket(s), prefix, capabilities, expiry. Bandwidth Alliance. Cloudflare-led group of providers that reduce or waive transfer fees between members. Backblaze is a founding member. B2 Cloud Storage. Backblaze’s S3-compatible object storage service. B2 Neo. White-label B2 for neocloud operators, with Partner API, custom domains, SSO. B2 Overdrive. Dedicated high-throughput B2 tier: 100 Gbps to 1 Tbps, unlimited free egress, from $15/TB, multi-PB commit. B2 Reserve. Legacy/channel prepaid capacity SKU name. Confirm current status. Byte-hour. Billing unit: storage measured continuously and averaged over the month. Class A/B/C/D transactions. B2 API call classes. A, B, C free; D (outbound event notifications) charged after 2,500/day. Cloud Replication. B2 feature copying objects between buckets, within or across regions (cross-region needs a second account). Compliance mode. Object Lock mode where retention cannot be shortened or removed by anyone. CoreWeave AI Object Storage / LOTA. CoreWeave’s object storage with a distributed cache (LOTA); Backblaze powers HDD tiers beneath it. Drive Stats. Backblaze’s public quarterly hard drive reliability reports. Egress. Data transferred out of a storage provider. Erasure coding (Reed-Solomon). Splitting data into data and parity shards; B2 uses 17+3 across 20 pods. Event Notifications. B2 webhooks on object create/update/delete, optional HMAC signing. Fireball. Backblaze’s 96 TB Synology NAS shipped to customers for offline data ingest. Governance mode. Object Lock mode where privileged keys can modify or remove retention. Groups / Organizations. Multi-account administration and billing. Hide marker. B2 version marker that hides a file (S3 delete marker equivalent). Hot tier. Fast storage (flash, parallel FS) for the active working set. Legal hold. Object Lock protection with no expiry until removed. Lifecycle rules. B2 rules to hide and delete versions and cancel unfinished large files by prefix; up to 100 per bucket. Live Read. Read/edit large media files while still uploading. MCP (Model Context Protocol). Standard for AI agents to discover and call tools. Backblaze B2 MCP Server exposes 40 tools gated by key capabilities. Multipart upload / large file. Uploading an object in parts; B2 native calls it “large file”. Native API. B2’s own API (b2_* calls), alongside the S3-compatible API. Neocloud. GPU-as-a-Service provider outside the hyperscalers. Object Lock. WORM immutability for objects; 1 to 3,000 days; formerly “File Lock”. Partner API. B2 API to create and manage accounts, usage, billing; used by MSPs, B2 Neo, Powered by Backblaze. Partner egress. Unlimited free egress from B2 to listed CDN and compute partners. Powered by Backblaze. Program to embed B2 inside a partner’s product. Presigned URL. Time-limited URL granting GET or PUT on one object without sharing keys. Read multiple. Monthly egress divided by stored data. Key TCO input. Region. B2 data location chosen at account creation: US West, US East, EU Central, CA East. SigV4. AWS Signature Version 4, required by B2’s S3 API. SOBR. Veeam Scale-Out Backup Repository; B2 can be the capacity tier. SSE-B2 / SSE-C. Server-side encryption with Backblaze-managed or customer-provided keys, AES-256. Storage pod. Backblaze’s storage server design; 20 pods form a vault. Tome. The set of drives in the same slot across a vault’s 20 pods; a file lives on one tome. TPN Blue Shield. Trusted Partner Network status aligned with MPA content security practices. UDM (Universal Data Migration). Backblaze-run migration service with cost relief for qualifying commitments. Vault (Backblaze Vault). 20 storage pods across 20 cabinets storing erasure-coded data. WORM. Write once, read many.