On Fri, May 10, 2024 at 11:18 AM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > On Fri, May 10, 2024 at 10:43:20AM +0800, Zhaoyang Huang wrote: > > Thanks for the prompt. I did some basic research on soft RAID and > > wonder if applying the bps limit on /dev/md0 like below could make > > this work. > > No. Look at btrfs' raid support, for example. it doesn't use md0. If I understand the below command correctly, btrfs uses one of the volumes within RAID as the mount block device, not /dev/md0. However, I think this is a problem of blkio.throttle rather than this commit which means this readahead budget control will work accordingly as long as blkio.throttle's parameter is configured correctly(eg. 50/50 on sdb and sdc) mkfs.btrfs -m raid0 -d raid0 /dev/sdb /dev/sdc mount -t btrfs /dev/sdb /mnt/btr > > > I didn't find information about 'RAID internally'. Could we set the > > limit on the root device(the one used for mount) to manage the whole > > partition without caring about where the bio finally goes? Or ask the > > user to decide if to use by making sure the device they apply will not > > do RAID? > > No.
