Is Btrfs optimized for SSD?

[66carolin]

Please give me some comments or suggestion about it.

[WebMaster]

There are some optimizations for SSD drives, and you can enable them by mounting with -o ssd. As of 2.6.31-rc1, this mount option will be enabled if Btrfs is capable to detect non-rotating storage. SSD is going to be a big part of future storage, and the Btrfs build plan on tuning for it heavily.

[66carolin]

What is CRFS? Is it related to Btrfs?
Please give me some suggestion about it.

[WebMaster]

CRFS, which was created at the same time Btrfs was, is a network file system protocol. The wire format for it utilizes a combination of btrfs disk formats and crfsd, while the server implementation utilizes Btrfs to store the data on disk.

[66carolin]

Will Btrfs be in the mainline Linux Kernel?

[WebMaster]

Btrfs is already in the mainline Linux kernel. It was merged on 9th January 2009, and was valid in the Linux 2.6.29 release.

[66carolin]

Does Btrfs run with older kernels?

[WebMaster]

v0.16 of Btrfs maintains suitability with kernels back to 2.6.18. Kernels older than that will not work.
The resent Btrfs unstable repositories only work against the mainline kernel. Once Btrfs is in mainline a backport repository will be made again.

[66carolin]

What is the difference between mount -o ssd and mount -o ssd_spread?

[WebMaster]

Mount -o ssd_spread is much more strict about searching a big unused area of the disk for new allotment, which tends to fragment the free space more over time. Mount -o ssd_spread is often faster on the less expensive SSD devices. The default for autodetected SSD devices is mount -o ssd.