Hi Dave
 
Have you looked at the Intel P4600 vsd the P4500
 
The P4600 has better random writes and a better drive writes per day I
believe
 
Thanks Joe

>>> <[email protected]> 11/13/2018 8:45 PM >>>

Thanks Merrick!
 
I checked with Intel spec [1], the performance Intel said is, 
 
·  Sequential Read (up to) 500 MB/s 
·  Sequential Write (up to) 330 MB/s 
·  Random Read (100% Span) 72000 IOPS 
·  Random Write (100% Span) 20000 IOPS
 
I think these indicator should be must better than general HDD, and I
have run read/write commands with “rados bench” respectively,   there
should be some difference.
 
And is there any kinds of configuration that could give us any
performance gain with this SSD (Intel S4500)?
 
[1]
https://ark.intel.com/products/120521/Intel-SSD-DC-S4500-Series-480GB-2-5in-SATA-6Gb-s-3D1-TLC-
 
Best Regards,
Dave Chen
 
From: Ashley Merrick <[email protected]> 
Sent: Wednesday, November 14, 2018 12:30 PM
To: Chen2, Dave
Cc: ceph-users
Subject: Re: [ceph-users] Benchmark performance when using SSD as the
journal
 

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Please report any suspicious attachments, links, or requests for
sensitive information.

Only certain SSD's are good for CEPH Journals as can be seen @
https://www.sebastien-han.fr/blog/2014/10/10/ceph-how-to-test-if-your-ssd-is-suitable-as-a-journal-device/

 

The SSD your using isn't listed but doing a quick search online it
appears to be a SSD designed for read workloads as a "upgrade" from a HD
so probably is not designed for the high write requirements a journal
demands. 

Therefore when it's been hit by 3 OSD's of workloads your not going to
get much more performance out of it than you would just using the disk
as your seeing.

 

On Wed, Nov 14, 2018 at 12:21 PM <[email protected]> wrote:



Hi all,
 
We want to compare the performance between HDD partition as the journal
(inline from OSD disk) and SSD partition as the journal, here is what we
have done, we have 3 nodes used as Ceph OSD,  each has 3 OSD on it.
Firstly, we created the OSD with journal from OSD partition, and run
“rados bench” utility to test the performance, and then migrate the
journal from HDD to SSD (Intel S4500) and run “rados bench” again, the
expected result is SSD partition should be much better than HDD, but the
result shows us there is nearly no change,
 
The configuration of Ceph is as below,
pool size: 3
osd size: 3*3
pg (pgp) num: 300
osd nodes are separated across three different nodes
rbd image size: 10G (10240M)
 
The utility I used is,
rados bench -p rbd $duration write
rados bench -p rbd $duration seq
rados bench -p rbd $duration rand
 
Is there anything wrong from what I did?  Could anyone give me some
suggestion?
 
 
Best Regards,
Dave Chen
 

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