I found this without much effort. http://www.sebastien-han.fr/blog/2012/11/15/make-your-rbd-fly-with-flashcache/
On Mon, Oct 7, 2013 at 11:39 AM, Jason Villalta <ja...@rubixnet.com> wrote:
> I also would be interested in how bcache or flashcache would integrate.
>
>
> On Mon, Oct 7, 2013 at 11:34 AM, Martin Catudal <mcatu...@metanor.ca>wrote:
>
>> Thank's Mike,
>> Kyle Bader suggest me also to use my large SSD (900 GB) as cache
>> drive using "bcache" or "flashcache".
>> Since I have already plan to use SSD for my journal, I would certainly
>> use also SSD as cache drive in addition.
>>
>> I will have to read documentation about "bcache" and his integration
>> with Ceph.
>>
>> Martin
>>
>> Martin Catudal
>> Responsable TIC
>> Ressources Metanor Inc
>> Ligne directe: (819) 218-2708
>>
>> Le 2013-10-07 11:25, Mike Lowe a écrit :
>> > Based on my experience I think you are grossly underestimating the
>> expense and frequency of flushes issued from your vm's. This will be
>> especially bad if you aren't using the async flush from qemu >= 1.4.2 as
>> the vm is suspended while qemu waits for the flush to finish. I think your
>> best course of action until the caching pool work is completed (I think I
>> remember correctly that this is currently in development) is to either use
>> the ssd's as large caches with bcache or to use them for journal devices.
>> I'm sure there are some other more informed opinions out there on the best
>> use of ssd's in a ceph cluster and hopefully they will chime in.
>> >
>> > On Oct 6, 2013, at 9:23 PM, Martin Catudal <mcatu...@metanor.ca> wrote:
>> >
>> >> Hi Guys,
>> >> I read all Ceph documentation more than twice. I'm now very
>> >> comfortable with all the aspect of Ceph except for the strategy of
>> using
>> >> my SSD and HDD.
>> >>
>> >> Here is my reflexion
>> >>
>> >> I've two approach in my understanding about use fast SSD (900 GB) for
>> my
>> >> primary storage and huge but slower HDD (4 TB) for replicas.
>> >>
>> >> FIRST APPROACH
>> >> 1. I can use PG with cache write enable as my primary storage that's
>> >> goes on my SSD and let replicas goes on my 7200 RPM.
>> >> With the cache write enable, I will gain performance for my VM
>> >> user machine in VDI environment since Ceph client will not have to wait
>> >> for the replicas write confirmation on the slower HDD.
>> >>
>> >> SECOND APPROACH
>> >> 2. Use pools hierarchies and let's have one pool for the SSD as primary
>> >> and lets the replicas goes to a second pool name platter for HDD
>> >> replication.
>> >> As explain in the Ceph documentation
>> >> rule ssd-primary {
>> >> ruleset 4
>> >> type replicated
>> >> min_size 5
>> >> max_size 10
>> >> step take ssd
>> >> step chooseleaf firstn 1 type host
>> >> step emit
>> >> step take platter
>> >> step chooseleaf firstn -1 type host
>> >> step emit
>> >> }
>> >>
>> >> At this point, I could not figure out what approach could have the most
>> >> advantage.
>> >>
>> >> Your point of view would definitely help me.
>> >>
>> >> Sincerely,
>> >> Martin
>> >>
>> >> --
>> >> Martin Catudal
>> >> Responsable TIC
>> >> Ressources Metanor Inc
>> >> Ligne directe: (819) 218-2708
>> >> _______________________________________________
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>> >> ceph-users@lists.ceph.com
>> >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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>
>
>
> --
> --
> *Jason Villalta*
> Co-founder
> [image: Inline image 1]
> 800.799.4407x1230 | www.RubixTechnology.com<http://www.rubixtechnology.com/>
>
--
--
*Jason Villalta*
Co-founder
[image: Inline image 1]
800.799.4407x1230 | www.RubixTechnology.com<http://www.rubixtechnology.com/>
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