[Gluster-devel] Just a thought, a better way to rebuild replica when some bricks go down rather than replace-brick

[Jaden Liang]

Hi all,

As I know, glusterfs have to replace brick to rebuild replica when some bricks go down. In most commercial distributed storage system, there is a key spec that indicates how fast to rebuild data when some components broke. In glusterfs, the replace-brick operation only use 1 on 1 to rebuild replica, this can not  use the cluster disks performance to increase the rebuild job that some companies called it RAID2.0. Therefore, I have some thoughts what to discuss.

Glusterfs use one single storage graph in a volume, like M x N distributed-replicated volume. This storage graph is global for all files in the same volume. From what I know in VMWare vSAN, vSAN use different graphs for different files, which means, every file has its own storage graph. In this case, file replica rebuild or file rebalance could do mush flexible than single global graph. If some brick goes down, it can just modify those storage graphs of files which lost replica, then rebuild can be run which replace-brick operations.

Just a thought, any suggestion would be great!

Best regards,
Jaden Liang
5/25/2017