{"id":49562898,"url":"https://github.com/nikitadev-work/system-design-practice","last_synced_at":"2026-05-03T10:46:40.472Z","repository":{"id":339174728,"uuid":"1160143161","full_name":"nikitadev-work/system-design-practice","owner":"nikitadev-work","description":"System design practice","archived":false,"fork":false,"pushed_at":"2026-02-22T14:04:42.000Z","size":354,"stargazers_count":0,"open_issues_count":0,"forks_count":0,"subscribers_count":0,"default_branch":"main","last_synced_at":"2026-05-03T10:46:39.152Z","etag":null,"topics":["rest-api","system-design"],"latest_commit_sha":null,"homepage":"","language":null,"has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":null,"status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/nikitadev-work.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":null,"code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null,"zenodo":null,"notice":null,"maintainers":null,"copyright":null,"agents":null,"dco":null,"cla":null}},"created_at":"2026-02-17T15:40:58.000Z","updated_at":"2026-02-22T14:04:46.000Z","dependencies_parsed_at":null,"dependency_job_id":null,"html_url":"https://github.com/nikitadev-work/system-design-practice","commit_stats":null,"previous_names":["nikitadev-work/system-design-practice"],"tags_count":0,"template":false,"template_full_name":null,"purl":"pkg:github/nikitadev-work/system-design-practice","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/nikitadev-work%2Fsystem-design-practice","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/nikitadev-work%2Fsystem-design-practice/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/nikitadev-work%2Fsystem-design-practice/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/nikitadev-work%2Fsystem-design-practice/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/nikitadev-work","download_url":"https://codeload.github.com/nikitadev-work/system-design-practice/tar.gz/refs/heads/main","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/nikitadev-work%2Fsystem-design-practice/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":32566444,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-05-03T06:36:36.687Z","status":"ssl_error","status_checked_at":"2026-05-03T06:36:09.306Z","response_time":103,"last_error":"SSL_read: unexpected eof while reading","robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":false,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["rest-api","system-design"],"created_at":"2026-05-03T10:46:39.758Z","updated_at":"2026-05-03T10:46:40.465Z","avatar_url":"https://github.com/nikitadev-work.png","language":null,"funding_links":[],"categories":[],"sub_categories":[],"readme":"Практика **System Design**\n\n**Тема**: Социальная сеть\n\nФункциональные требования:\n  - добавление и удаление друзей\n  - просмотр друзей пользователя\n  - просмотр профиля пользователя\n  - публикация поста в ленту\n  - загрузка медиа файлов для постов\n  - просмотр ленты постов\n  - просмотр диалогов и чатов пользователя\n  - отправка и чтение сообщений\n\nНефункциональные требования\n\nDAU: 55 000 000 пользователей\n\nСообщения:\n- Один пользователь в день пишет: 35 сообщений\n- Один пользователь в день читает: 200 сообщений\n- Средняя длина сообщения: 60 символов\n\nПосты и лента:\n- Один пользователь в день просматривает: 120 постов\n- Один пользователь в день ставит: 25 лайков\n- Один пользователь в день пишет: 3 комментария\n- Один пользователь публикует: 0.2 поста\n- Средняя длина поста: 500 символов\n\nПрофиль и социальный граф:\n- Среднее количество друзей у пользователя: 200\n- Среднее количество подписок: 150\n- Среднее количество подписчиков: 200\n\nМедиа:\n- Один пользователь в день загружает: 0.3 медиа-файла\n- Средний размер фото: 2 MB\n- Средний размер видео: 50 MB\n\n![Schema](Schema.png)\n\n## Расчеты\n\n### Размер базы данных для хранения сообщений на 5 лет\n\nРазмер текста сообщений за день:  \n55 000 000 * 35 * 60 * 2 байт = 231 GB/день  \n\nЗа год:  \n231 * 365 ≈ 84 TB  \n\nЗа 5 лет:  \n≈ 420 TB без репликации  \n\nС 2х факторной репликацией:  \n≈ 840 TB  \n\n\n### Расчет для одной реплики\n\nРассматриваем HDD на 6 TB:  \n400 / 6 = 67 дисков  \n\nШардирование:  \nпо 8 дисков на шарде → 9 шардов  \n\n\n### Входящий трафик на создание постов\n\nКоличество постов в день:  \n55 000 000 * 0.2 = 11 000 000  \n\nЕсли считать, что все посты текстовые:  \n11 000 000 * 500 * 2 = 11 000 000 000 байт ≈ 11 GB/день  \n\n\n### RPS\n\nRPS по созданию постов:  \n11 000 000 / 86 400 ≈ 128 posts/s  \n\nRPS по чтению постов:  \n55 000 000 * 120 / 86 400 ≈ 77 000 posts/s\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fnikitadev-work%2Fsystem-design-practice","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fnikitadev-work%2Fsystem-design-practice","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fnikitadev-work%2Fsystem-design-practice/lists"}