Re: CephFS kernel driver is 10-15x slower than FUSE driver

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Try running your initial test in reverse. Copy or of fuse first and then the kennel driver. I think you'll find that you are dealing with more than 1 later of caching affecting this test. Caching on the OSD and kernel caching primarily.


On Sat, Apr 8, 2017, 8:04 PM Deepak Naidu <dnaidu@xxxxxxxxxx> wrote:
Hmm pretty odd. When I ran test on ceph kernel vs ceph fuse , FUSE has always been slower for both read and writes. 

Try using tools like fio to run IO test with directIO(bypass system cache)

--
Deepak

On Apr 8, 2017, at 4:50 PM, Kyle Drake <kyle@xxxxxxxxxxxxx> wrote:

Pretty much says it all. 1GB test file copy to local:

$ time cp /mnt/ceph-kernel-driver-test/test.img .

real 2m50.063s
user 0m0.000s
sys 0m9.000s

$ time cp /mnt/ceph-fuse-test/test.img .

real 0m3.648s
user 0m0.000s
sys 0m1.872s

Yikes. The kernel driver averages ~5MB and the fuse driver averages ~150MBish? Something crazy is happening here. It's not caching, I ran both tests fresh.

Ubuntu 16.04.2, 4.4.0-72-generic, ceph-fuse 10.2.6-1xenial, ceph-fs-common 10.2.6-0ubuntu0.16.04.1 (I also tried the 16.04.2 one, same issue).

Anyone run into this? Did a lot of digging on the ML and didn't see anything. I'm was going to use FUSE for production, but it tends to lag more on a lot of small requests so I had to fall back the kernel driver.
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