--- title: All Your GUCs in a Row: data_directory_mode | daily.dev description: PostgreSQL's `data_directory_mode` GUC is a read-only parameter that reports whether the data directory uses `0700` (owner-only) or `0750` (group-readable)... canonical: https://daily.dev/posts/all-your-gucs-in-a-row-data-directory-mode-bopbesycd twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: All Your GUCs in a Row: data_directory_mode | daily.dev og:description: PostgreSQL's `data_directory_mode` GUC is a read-only parameter that reports whether the data directory uses `0700` (owner-only) or `0750` (group-readable)... og:url: https://daily.dev/posts/all-your-gucs-in-a-row-data-directory-mode-bopbesycd og:image: https://api.daily.dev/og/posts/BopbeSyCd.png og:image:alt: All Your GUCs in a Row: data_directory_mode og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # All Your GUCs in a Row: data_directory_mode **[Planet PostgreSQL](https://daily.dev/sources/planet-postgresql)** · 3 min read · 0 upvotes · 0 comments ## Summary PostgreSQL's `data_directory_mode` GUC is a read-only parameter that reports whether the data directory uses `0700` (owner-only) or `0750` (group-readable) Unix permissions. Through PostgreSQL 10, only `0700` was accepted; PostgreSQL 11 added `initdb --allow-group-access` to enable `0750`, allowing unprivileged users in the postgres group to read files without write access. This is primarily useful for backup processes (`pg_basebackup`, `pg_receivewal`, `pg_recvlogical`) that need to copy data files without running as a superuser. The GUC exists so SQL clients without shell access can query this permission state. Changing permissions on an existing cluster requires a full shutdown and manual `chmod` of all files — the GUC itself is never modified directly. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [All Your GUCs in a Row: data\_directory](https://daily.dev/posts/all-your-gucs-in-a-row-data-directory-nyewadaef) · Planet PostgreSQL · 0 upvotes · 0 comments - [All Your GUCs in a Row: log\_directory, log\_filename, and log\_file\_mode](https://daily.dev/posts/all-your-gucs-in-a-row-log-directory-log-filename-and-log-file-mode-krhdncyzp) · Planet PostgreSQL · 0 upvotes · 0 comments - [All Your GUCs in a Row: external\_pid\_file](https://daily.dev/posts/all-your-gucs-in-a-row-external-pid-file-t7mm1hv7k) · Planet PostgreSQL · 0 upvotes · 0 comments - [All Your GUCs in a Row: data\_checksums](https://daily.dev/posts/all-your-gucs-in-a-row-data-checksums-w5hyxxpgp) · Planet PostgreSQL · 0 upvotes · 0 comments - [All Your GUCs in a Row: config\_file](https://daily.dev/posts/all-your-gucs-in-a-row-config-file-53spmxdlx) · Planet PostgreSQL · 0 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security), [#postgresql](https://daily.dev/tags/postgresql) [View this post on daily.dev](https://daily.dev/posts/all-your-gucs-in-a-row-data-directory-mode-bopbesycd) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"All Your GUCs in a Row: data_directory_mode","url":"https://daily.dev/posts/all-your-gucs-in-a-row-data-directory-mode-bopbesycd","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/all-your-gucs-in-a-row-data-directory-mode-bopbesycd"},"datePublished":"2026-06-07T01:01:48.372Z","dateModified":"2026-06-07T01:02:15.106Z","description":"PostgreSQL's `data_directory_mode` GUC is a read-only parameter that reports whether the data directory uses `0700` (owner-only) or `0750` (group-readable)...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/a52ee8a48e6a01ca6190a99c71f793e8?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/a52ee8a48e6a01ca6190a99c71f793e8?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Planet PostgreSQL","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Planet PostgreSQL","logo":"https://media.daily.dev/image/upload/logos/placeholder.jpg","url":"https://daily.dev/sources/planet-postgresql"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/all-your-gucs-in-a-row-data-directory-mode-bopbesycd","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"security,postgresql","timeRequired":"PT3M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Planet PostgreSQL","item":"https://daily.dev/sources/planet-postgresql"},{"@type":"ListItem","position":3,"name":"All Your GUCs in a Row: data_directory_mode"}]} ```