> [[Benchmark]]
> Since I have upgraded my rig to all NVME storage, there is no HDD
> test result.
>
> Physical device: NVMe SSD
> VM device: VirtIO block device, backup by sparse file
> Nodesize: 4K (to bump up tree height)
> Extent data size: 4M
> Fs size used: 1T
>
> All file extents on disk is in 4M size, preallocated to reduce space usage
> (as the VM uses loopback block device backed by sparse file)
Do you have a some additional details about the test setup? I tried to
do the same (testing) for a bug Felix (added to Cc) reported to my at
the ALPSS Conference and I couldn't reproduce the issue.
My testing was a 100TB sparse file passed into a VM and running this
script to touch all blockgroups:
#!/bin/sh
FILE=/mnt/test
add_dirty_bg() {
off="$1"
len="$2"
touch $FILE
xfs_io -c "falloc $off $len" $FILE
rm $FILE
}
mkfs.btrfs /dev/vda
mount /dev/vda /mnt
for ((i = 1; i < 100000; i++)); do
add_dirty_bg $i"G" "1G"
done
umount /mnt
--
Johannes Thumshirn SUSE Labs Filesystems
jthumshirn@xxxxxxx +49 911 74053 689
SUSE Software Solutions Germany GmbH
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