>> 3. After the test, in a.txt, we got bw=1162.7MB/s, in b.txt, we get
>> bw=3579.6MB/s.
mostly, due to your kernel buffer of client host
------------------ Original ------------------
From: "Somnath Roy"<somnath....@sandisk.com>;
Date: Mon, Dec 12, 2016 09:47 AM
To: "V Plus"<v.plussh...@gmail.com>; "CEPH list"<ceph-users@lists.ceph.com>;
Subject: Re: [ceph-users] Ceph performance is too good (impossible..)...
Fill up the image with big write (say 1M) first before reading and you should
see sane throughput.
Thanks & Regards
Somnath
From: ceph-users [mailto:ceph-users-boun...@lists.ceph.com] On Behalf Of V Plus
Sent: Sunday, December 11, 2016 5:44 PM
To: ceph-users@lists.ceph.com
Subject: [ceph-users] Ceph performance is too good (impossible..)...
Hi Guys,
we have a ceph cluster with 6 machines (6 OSD per host).
1. I created 2 images in Ceph, and map them to another host A (outside the Ceph
cluster). On host A, I got /dev/rbd0 and /dev/rbd1.
2. I start two fio job to perform READ test on rbd0 and rbd1. (fio job
descriptions can be found below)
"sudo fio fioA.job -output a.txt & sudo fio fioB.job -output b.txt & wait"
3. After the test, in a.txt, we got bw=1162.7MB/s, in b.txt, we get
bw=3579.6MB/s.
The results do NOT make sense because there is only one NIC on host A, and its
limit is 10 Gbps (1.25GB/s).
I suspect it is because of the cache setting.
But I am sure that in file /etc/ceph/ceph.conf on host A,I already added:
[client]
rbd cache = false
Could anyone give me a hint what is missing? why....
Thank you very much.
fioA.job:
[A]
direct=1
group_reporting=1
unified_rw_reporting=1
size=100%
time_based=1
filename=/dev/rbd0
rw=read
bs=4MB
numjobs=16
ramp_time=10
runtime=20
fioB.job:
[B]
direct=1
group_reporting=1
unified_rw_reporting=1
size=100%
time_based=1
filename=/dev/rbd1
rw=read
bs=4MB
numjobs=16
ramp_time=10
runtime=20
Thanks...
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