Site Health Warning: Disk Space Check Unavailable

WordPress Site Health sometimes shows a warning that reads:

Could not determine available disk space for updates (disk_free_space and shell access are both unavailable on this host).

This page explains what that means, whether you should care, and what to do about it.

What is happening #

Since WordPress 6.3, Site Health includes a check called “Available disk space”. It asks the server how much free disk space remains before WordPress performs updates, so updates never run out of space halfway through.

The check uses a PHP function called disk_free_space(). Many hosts disable this function for security hardening, and some also block the shell access that WordPress could use as a fallback. When both are unavailable, WordPress cannot read the disk at all and shows this warning.

This is a host restriction, not a problem with your site.

Does it matter? #

For most sites: no. The check is marked recommended, not critical. WordPress updates still run normally; WordPress simply cannot verify free space before starting.

The only real risk is a server disk that is genuinely nearly full: without this check, WordPress will not warn you in advance, and an update could fail when the disk fills up. If your site is small and your host is not warning you about disk usage, this is a cosmetic warning you can safely ignore.

How to check disk usage another way #

• Host control panel: most panels (cPanel, hPanel, GridPane, your host’s file manager) show disk usage per account or per site.
• SSH: run df -h to see free space across all partitions.
• Managed hosts: your host monitors disk usage and alerts you before it becomes a problem (GridPane, for example, notifies at 80% usage).

How to fix it for real #

The only proper fix is host-side, because the function is disabled at the PHP level and no plugin or theme can override that:

1. Ask your host to enable disk_free_space (and disk_total_space) for your site’s PHP.
2. On self-managed servers (GridPane and similar), remove those functions from the site’s PHP disable_functions setting and reload PHP-FPM.
3. Rerun Site Health. If disk space now shows, the warning is gone for good.

If your host refuses, this is one of the few Site Health warnings you can live with. Just keep an eye on disk usage through your control panel instead.

What Xpulse does about it #

Xpulse reads disk space through the same PHP function, so on hosts that block it, Xpulse shows disk space as unavailable too. That is not a fault in your site and not a missing feature: the server simply does not expose the number.

Xpulse still detects what matters through its own scanners: database bloat, site footprint, and server resource health all work independently of this check. If your readiness report shows no disk problems otherwise, this Site Health warning does not affect your migration.