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View Full Version : Is /dev/sda1 file-backed or device-backed?


greenrd
03-12-2005, 12:16 AM
Are the root devices on our servers, like /dev/sda1, backed by a device (e.g. a partition or an LVM volume), or a file, on the host?

In other words, are they phy: devices or file: devices?

The reason I ask is because, in several places I have read that it is not safe to use a journalled filesystem on a file-backed device - UNLESS the file is written synchonously - because otherwise writes might be made out-of-order, causing filesystem inconsistencies if there is a crash or power failure.

matta
03-12-2005, 01:45 AM
Both the root filesystem and swap is backed by LVM. We tried files at first, but performance was horrible. Using LVM is why we also can't oversell disk space.