It's probably more a question of IOPS unless you have really slow SSDs. :)
Mark
On 04/02/2015 07:22 AM, Sreenath BH wrote:
We have the model with 25 disks per node.
We have just two 10G network interfaces per node. Does that not limit
the thgouthput and hence the load on the CPUs?
-Sreenath
On 4/2/15, Alexandre DERUMIER <aderumier@xxxxxxxxx> wrote:
Hi,
with HP SL4540 server?
this model http://www8.hp.com/h20195/v2/GetDocument.aspx?docname=c04128155
?
(60 drives ?)
I think for a full ssd node, it'll be impossible to reach max performance,
you'll be cpu bound.
I think a small node with 6-8 ssd osd for 20cores should be ok.
----- Mail original -----
De: "Sreenath BH" <bhsreenath@xxxxxxxxx>
À: "Christian Balzer" <chibi@xxxxxxx>
Cc: "ceph-users" <ceph-users@xxxxxxxxxxxxxx>
Envoyé: Jeudi 2 Avril 2015 11:55:52
Objet: Re: Cores/Memory/GHz recommendation for SSD based
OSD servers
Thanks for the tips.
Could anyone share their experience building a SSD pool or a SSD cache
tier with HP SL4540 server?
rgds,
Sreenath
On 4/2/15, Christian Balzer <chibi@xxxxxxx> wrote:
Hello,
On Wed, 1 Apr 2015 18:40:10 +0530 Sreenath BH wrote:
Hi all,
we are considering building all SSD OSD servers for RBD pool.
I'd advise you to spend significant time reading the various threads in
this ML about SSD based pools.
Both about the current shortcomings and limitations of SSD pools and which
SSDs to (not) use.
Couple of questions:
Does Ceph have any recommendation for number of cores/memory/ghz per
SSD drive, similar to what is usually followed for hard drives(1
core/1 GB Ram/1Ghz speed)?
Note that that 1GHz core per OSD only applies with pure HDD OSDs, once a
journal SSD enters the picture you're likely to want 2-3 times that.
You probably don't want to try this with anything less than the
upcoming Hammer release, but even with that the current rule for SSD based
pools is "the fastest cores you can afford and as many as possible".
And given the right loads, small write IOPS basically, you're probably
still going to be CPU bound.
RAM is the same as with HDD based OSDs, but given how much more RAM helps
I would advise at least 2GB per OSD and as much as you can afford.
Regards,
Christian
thanks,
Sreenath
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Christian Balzer Network/Systems Engineer
chibi@xxxxxxx Global OnLine Japan/Fusion Communications
http://www.gol.com/
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