"rbd rm image" slow with big images ?

[Alexandre DERUMIER <aderumier@odiso.com>]

Hi,

I trying to delete some rbd images with rbd rm,
and it seem to be "slow" with big images.



I'm testing it with just create a new image (1TB):

# time rbd -p pool1 create --size 1000000 image2

real    0m0.031s
user    0m0.015s
sys     0m0.010s


then just delete it, without having writed nothing in image


# time rbd -p pool1 rm image2
Removing image: 100% complete...done.

real    1m45.558s
user    0m14.683s
sys     0m17.363s



same test with 100GB

# time rbd -p pool1 create --size 100000 image2

real    0m0.032s
user    0m0.016s
sys     0m0.007s

# time rbd -p pool1 rm image2
Removing image: 100% complete...done.

real    0m10.499s
user    0m1.488s
sys     0m1.720s


I'm using journal in tmpfs, 3 servers, 15 osds with 1disk 15K (xfs)
network bandwith,diskio,cpu are low.

Is it the normal behaviour ? Maybe some xfs tuning could help ?