g2p / Bcache Tools

These are the userspace tools required for bcache.

Bcache is a patch for the Linux kernel to use SSDs to cache other block devices. For more information, see http://bcache.evilpiepirate.org. Documentation for the run time interface is included in the kernel tree, in Documentation/bcache.txt.

Included:

make-bcache Formats a block device for use with bcache. A device can be formatted for use as a cache or as a backing device (requires yet to be implemented kernel support). The most important option is for specifying the bucket size. Allocation is done in terms of buckets, and cache hits are counted per bucket; thus a smaller bucket size will give better cache utilization, but poorer write performance. The bucket size is intended to be equal to the size of your SSD's erase blocks, which seems to be 128k-512k for most SSDs; feel free to experiment.

bcache-super-show Prints the bcache superblock of a cache device or a backing device.

Udev rules The first half of the rules do auto-assembly and add uuid symlinks to cache and backing devices. If util-linux's libblkid is sufficiently recent (2.24) the rules will take advantage of the fact that bcache has already been detected. Otherwise they call a small probe-bcache program that imitates blkid.

The second half of the rules add symlinks to cached devices, which are the devices created by the bcache kernel module.

Initramfs support Currently initramfs-tools, mkinitcpio and dracut are supported.