Re: RBD fio Performance concerns

[Stefan Priebe - Profihost AG <s.priebe@profihost.ag>]

Am 22.11.2012 15:52, schrieb Alexandre DERUMIER:
>>> I discussed this with somebody frmo inktank. Had to search the
>>> mailinglist. It might be OK if you're working with enough replicas and UPS.
>>>
>>> I see no other option while working with SSDs - the only Option would be
>>> to be able to deaktivate the journal at all. But ceph does not support this.
>
> Do you have a big difference with putting 1 journal by osd on each ssd drive ?

Not tested.

> another alternative can be (but indeed costly):
>
> - stec zeus ram ssd drive, around 2000$ for 8G (I have benched it around 100000 iops ;)
> - ddrdrive (http://www.ddrdrive.com/) (around 200000iops, don't know the price)
> - fusionio card (iodrive2, 360GB, around 3000€ , but they are 160GB model, maybe half the price)

All too expensive.

> - maybe ocz talos, around 600€ for OCZ Talos 2 R 200 Go (don't have benched them, but spec say around 35000iops random)
Not usable as each OSD can do 35.000 random IOP/s in my case and have 8 
of them in each node...

Stefan

> ----- Mail original -----
>
> De: "Stefan Priebe - Profihost AG" <s.priebe@profihost.ag>
> À: "Mark Nelson" <mark.nelson@inktank.com>
> Cc: "Alexandre DERUMIER" <aderumier@odiso.com>, "ceph-devel" <ceph-devel@vger.kernel.org>, "Mark Kampe" <mark.kampe@inktank.com>, "Sébastien Han" <han.sebastien@gmail.com>
> Envoyé: Jeudi 22 Novembre 2012 15:42:14
> Objet: Re: RBD fio Performance concerns
>
> Am 22.11.2012 15:37, schrieb Mark Nelson:
>> I don't think we recommend tmpfs at all for anything other than playing
>> around. :)
>
> I discussed this with somebody frmo inktank. Had to search the
> mailinglist. It might be OK if you're working with enough replicas and UPS.
>
> I see no other option while working with SSDs - the only Option would be
> to be able to deaktivate the journal at all. But ceph does not support this.
>
> Stefan
>
>> On 11/22/2012 08:22 AM, Stefan Priebe - Profihost AG wrote:
>>> Hi,
>>>
>>> can someone from inktank comment this? Might be using /dev/ram0 with an
>>> fs on it be better than tmpfs as we can use dio?
>>>
>>> Greets,
>>> Stefan
>>>
>>>> ----- Mail original -----
>>>>
>>>> De: "Stefan Priebe - Profihost AG" <s.priebe@profihost.ag>
>>>> À: "Sébastien Han" <han.sebastien@gmail.com>
>>>> Cc: "Mark Nelson" <mark.nelson@inktank.com>, "Alexandre DERUMIER"
>>>> <aderumier@odiso.com>, "ceph-devel" <ceph-devel@vger.kernel.org>,
>>>> "Mark Kampe" <mark.kampe@inktank.com>
>>>> Envoyé: Jeudi 22 Novembre 2012 14:29:03
>>>> Objet: Re: RBD fio Performance concerns
>>>>
>>>> Am 22.11.2012 14:22, schrieb Sébastien Han:
>>>>> And RAMDISK devices are too expensive.
>>>>>
>>>>> It would make sense in your infra, but yes they are really expensive.
>>>>
>>>> We need something like tmpfs - running in local memory but support dio.
>>>>
>>>> Stefan
>>>>
>>
>>
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