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此保留區(qū)有個(gè)作用是在磁盤被普通用戶寫滿后，root用戶可以繼續(xù)管理硬盤， Google一點(diǎn)資料分享給你看看
Saving space for important root processes (and possible rescue actions) is one reason.
But there's another. Ext3 is pretty good at avoiding filesystem fragmentation, but once you get above about 95% full, that behavior falls off the cliff, and suddenly filesystem performance becomes a mess. So leaving 5% reserved gives you a buffer against this.
Ext4 should be better at this, as explained by Linux filesystem developer/guru Theodore Ts'o:
If you set the reserved block count to zero, it won't affect performance much except if you run for long periods of time (with lots of file creates and deletes) while the filesystem is almost full (i.e., say above 95%), at which point you'll be subject to fragmentation problems. Ext4's multi-block allocator is much more fragmentation resistant, because it tries much harder to find contiguous blocks, so even if you don't enable the other ext4 features, you'll see better results simply mounting an ext3 filesystem using ext4 before the filesystem gets completely full.
If you are just using the filesystem for long-term archive, where files aren't changing very often (i.e., a huge mp3 or video store), it obviously won't matter. |
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發(fā)表于 2014-03-23 11:59
