I use ext4 drives for games and tend to fill them up. Do I need to leave a fixed amount of space free for performance or drive health, or does ext4 already set enough aside?
Do Windows free space rules apply to Linux drives too?
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Fenvor-6a
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There is no universal rule that says you need to leave 100 GB free, on Windows or Linux. The useful amount depends on the drive and what you do with it.
Don't run your system partition completely out of space, though. Linux needs room for things like logs, updates and temporary files. A separate game drive can be filled more closely, but you still need space for downloads and updates.
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SSD free space and ext4 reserved space are related but different things. An SSD controller uses spare flash capacity to manage writes and replace worn blocks. SSDs usually have some spare capacity built in, and leaving additional space unused can help, especially under heavy write workloads.
Free space inside a partition can be useful too. Make sure the system's TRIM setup is working so the SSD can be told which blocks are no longer in use. The exact benefit depends on the drive and workload, so a fixed number of gigabytes isn't a reliable health rule.
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Some of the apparent missing space isn't ext4 taking it. Drive makers commonly advertise capacity in decimal units, while many tools display capacity in binary units. A 2 TB drive shows up as roughly 1.82 TiB before filesystem overhead.
Ext4 also uses space for filesystem metadata and commonly reserves a percentage of blocks. Creating a partition doesn't mean ordinary file data has been written across the entire partition.
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For a dedicated ext4 game drive, check the reserved block percentage if you're trying to reclaim space. The common default is 5%, which can be a lot on a large drive. It can be adjusted with tune2fs.
I wouldn't blindly set it to zero on the system filesystem. Reserved blocks give privileged processes some room when the filesystem fills up, which can help keep the system manageable. Check which partition you're changing and what uses it first.
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Fenvor-6a:
So the reserved blocks aren't the whole reason a 2 TB drive looks smaller?
Nerlo.8w:
Right. The decimal versus binary unit difference accounts for much of that change. Metadata and reserved blocks can reduce the space available for ordinary use further.