Hi,
Plus reads will still come from your non-SSD disks unless you're using something like flashcache in front and as Greg said, having much more IOPS available for your db often makes a difference (depending on load, usage etc ofc).
Plus reads will still come from your non-SSD disks unless you're using something like flashcache in front and as Greg said, having much more IOPS available for your db often makes a difference (depending on load, usage etc ofc).
We're using Samsung Pro 840 256GB pretty much like Martin describes and we haven't had any issues (yet).
We've setup our environment so that if we lose a node or take one offline for maint it won't impact the cluster much; with only 3 nodes I would prob. go with more durable hw-specs.
We've setup our environment so that if we lose a node or take one offline for maint it won't impact the cluster much; with only 3 nodes I would prob. go with more durable hw-specs.
Cheers,
Martin
Martin
On Tue, Oct 22, 2013 at 6:38 AM, Gregory Farnum <greg@xxxxxxxxxxx> wrote:
On Mon, Oct 21, 2013 at 7:05 PM, Martin Catudal <mcatudal@xxxxxxxxxx> wrote:The specifics depend on a lot of factors, but for database
> Hi,
> I have purchase my hardware for my Ceph storage cluster but did not
> open any of my 960GB SSD drive box since I need to answer my question first.
>
> Here's my hardware.
>
> THREE server Dual 6 core Xeon 2U capable with 8 hotswap tray plus 2 SSD
> mount internally.
> In each server I will have :
> 2 x SSD 840 Pro Samsung 128 GB in RAID 1 for the OS
> 2 x SSD 840 Pro Samsung for journal
> 4 x 4TB Hitachi 7K4000 7200RPM
> 1 x 960GB Crucial M500 for one fast OSD pool.
>
> Configuration : One SSD journal for two 4TB so If I lost one SSD
> journal, I will only lost Two OSD instead of all my storage for that
> particular node.
>
> I have also bought 3 x 960GB M500 SSD from Crucial for the creation of a
> fast Pool of OSD made from SSD's. So One 960GB per server for database
> application.
> It is advisable to do that but it is better to return them and for the
> same price buy 6 more 4TB Hitachi?
>
> Since the write acknowledgment is made from the SSD journal, does I have
> a huge improvement by using SSD as OSD?
> My goal is to have solid fast performance for database ERP and 3D
> modeling of mining gallery run in VM.
applications you are likely to have better performance with an SSD
pool. This is because even though the journal can do fast
acknowledgements, that's for evening out write bursts — on average it
will restrict itself to the speed of the backing store. A good SSD can
generally do much more than 6x a HDD's random IOPS.
-Greg
Software Engineer #42 @ http://inktank.com | http://ceph.com
>
> Thank's
> Martin
>
> --
> Martin Catudal
> Responsable TIC
> Ressources Metanor Inc
> Ligne directe: (819) 218-2708
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