* rbd speed: write vs read
@ 2011-05-06 14:14 Fyodor Ustinov
2011-05-06 16:08 ` Sage Weil
0 siblings, 1 reply; 4+ messages in thread
From: Fyodor Ustinov @ 2011-05-06 14:14 UTC (permalink / raw)
To: ceph-devel
Hi!
oops. This my misconfiguration.
WBR,
Fyodor.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: rbd speed: write vs read
2011-05-06 14:14 rbd speed: write vs read Fyodor Ustinov
@ 2011-05-06 16:08 ` Sage Weil
2011-05-06 18:01 ` Fyodor Ustinov
0 siblings, 1 reply; 4+ messages in thread
From: Sage Weil @ 2011-05-06 16:08 UTC (permalink / raw)
To: Fyodor Ustinov; +Cc: ceph-devel
On Fri, 6 May 2011, Fyodor Ustinov wrote:
> Hi!
>
> oops. This my misconfiguration.
Out of curiousity, what was the misconfiguration?
Doing a streaming read in 10MB chunks when RBD is striped over 4MB
objects won't be terribly efficient. You should get the best sync read
performance when the object sizes match up. You'll get better performance
if whatever is sitting above the block layer dispatches multiple read
requests in parallel (i.e. something smarter than dd, like a file system).
sage
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: rbd speed: write vs read
2011-05-06 16:08 ` Sage Weil
@ 2011-05-06 18:01 ` Fyodor Ustinov
0 siblings, 0 replies; 4+ messages in thread
From: Fyodor Ustinov @ 2011-05-06 18:01 UTC (permalink / raw)
To: Sage Weil; +Cc: ceph-devel
On 05/06/2011 07:08 PM, Sage Weil wrote:
> On Fri, 6 May 2011, Fyodor Ustinov wrote:
>> Hi!
>>
>> oops. This my misconfiguration.
> Out of curiousity, what was the misconfiguration?
I have 20 OSD server. 10 in one vlan and 10 in other (btw, question: mon
server can listen on all ip addressessimultaneously?).
Because our NOC, 10 servers have anisotropic configuration - 800Mbps in
one direction and 150Mbps to another.
> Doing a streaming read in 10MB chunks when RBD is striped over 4MB
> objects won't be terribly efficient. You should get the best sync read
> performance when the object sizes match up. You'll get better performance
> if whatever is sitting above the block layer dispatches multiple read
> requests in parallel (i.e. something smarter than dd, like a file system).
Hmm. But it's linear read. I do not know how it works internally, but
did reading 10MB by 4MB chunk can not be executed in parallel?
WBR,
Fyodor.
^ permalink raw reply [flat|nested] 4+ messages in thread
* rbd speed: write vs read
@ 2011-05-06 13:58 Fyodor Ustinov
0 siblings, 0 replies; 4+ messages in thread
From: Fyodor Ustinov @ 2011-05-06 13:58 UTC (permalink / raw)
To: ceph-devel
Hi!
root@stb1:~# dd if=/dev/zero of=/dev/rbd0 bs=10240000
^C13217+0 records in
13217+0 records out
135342080000 bytes (135 GB) copied, 1135.75 s, 119 MB/s
root@stb1:~# dd if=/dev/rbd0 of=/dev/null bs=10240000
^C930+0 records in
929+0 records out
9512960000 bytes (9.5 GB) copied, 394.773 s, 24.1 MB/s
It's my misconfiguration?
P.S. 20 OSD servers, 2*1G ether.
WBR,
Fyodor.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2011-05-06 18:01 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2011-05-06 14:14 rbd speed: write vs read Fyodor Ustinov
2011-05-06 16:08 ` Sage Weil
2011-05-06 18:01 ` Fyodor Ustinov
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2011-05-06 13:58 Fyodor Ustinov
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