[pve-devel] less cores more iops / speed

[Stefan Priebe - Profihost AG]

Am 12.11.2012 15:43, schrieb Alexandre DERUMIER:
>>> So i just need to add auth supported=none on all ceph hosts?
> To be honest, I never setup it...
Will try that. I've asked ceph mailinglist.Im also waiting for an arista 
7150S series switch. Sadly they told me they're not able to deliver 
before january ;-(

Greets,
Stefan


> ----- Mail original -----
>
> De: "Stefan Priebe - Profihost AG" <s.priebe at profihost.ag>
> À: "Alexandre DERUMIER" <aderumier at odiso.com>
> Cc: pve-devel at pve.proxmox.com
> Envoyé: Lundi 12 Novembre 2012 15:40:12
> Objet: Re: [pve-devel] less cores more iops / speed
>
> Am 12.11.2012 15:26, schrieb Alexandre DERUMIER:
>> Maybe some tracing on kvm process could give us clues to find where the cpu is used ?
>>
>> Also another idea, can you try with "auth supported=none" ? maybe they are some overhead with ceph authenfication ?
>
> ceph.conf on all ceph hosts:
> [global]
> auth cluster required = cephx
> auth service required = cephx
> auth client required = cephx
> keyring = /etc/ceph/$name.keyring
>
> So i just need to add auth supported=none on all ceph hosts?
>
> Stefan
>
>> ----- Mail original -----
>>
>> De: "Alexandre DERUMIER" <aderumier at odiso.com>
>> À: "Stefan Priebe - Profihost AG" <s.priebe at profihost.ag>
>> Cc: pve-devel at pve.proxmox.com
>> Envoyé: Lundi 12 Novembre 2012 15:20:07
>> Objet: Re: [pve-devel] less cores more iops / speed
>>
>> Ok thanks.
>>
>> Seem to use a lot of cpu vs nfs,iscsi ...
>>
>> I hope that ceph dev will work on this soon !
>>
>>
>> ----- Mail original -----
>>
>> De: "Stefan Priebe - Profihost AG" <s.priebe at profihost.ag>
>> À: "Alexandre DERUMIER" <aderumier at odiso.com>
>> Cc: "eric" <eric at netwalk.com>, pve-devel at pve.proxmox.com
>> Envoyé: Lundi 12 Novembre 2012 15:05:08
>> Objet: Re: [pve-devel] less cores more iops / speed
>>
>> Am 12.11.2012 13:49, schrieb Alexandre DERUMIER:
>>>>> One VM on one Host: 18.000 IOP/s
>>>>> Two VM on one Host: 2x11.000 IOP/s
>>>>> Three VM on one Host: 3x7.000 IOP/s
>>>
>>> And host cpu is 100% ?
>>
>> No. For three VMs yes. For one and two no. I think librbd / rbd
>> implementation in kvm is the bottleneck here.
>>
>> Stefan
>>
>>> ----- Mail original -----
>>>
>>> De: "Stefan Priebe - Profihost AG" <s.priebe at profihost.ag>
>>> À: "Alexandre DERUMIER" <aderumier at odiso.com>
>>> Cc: "eric" <eric at netwalk.com>, pve-devel at pve.proxmox.com
>>> Envoyé: Lundi 12 Novembre 2012 12:58:35
>>> Objet: Re: [pve-devel] less cores more iops / speed
>>>
>>> Am 12.11.2012 08:51, schrieb Alexandre DERUMIER:
>>>>>> Right now RBD in KVM is limited by CPU speed.
>>>>
>>>> Good to known, so it's seem lack of threading, or maybe somes locks. (so faster cpu give more iops).
>>>>
>>>> If you lauch parallel fio on same host on different guest, do you get more total iops ? (for me it's scale)
>>>
>>> One VM on one Host: 18.000 IOP/s
>>> Two VM on one Host: 2x11.000 IOP/s
>>> Three VM on one Host: 3x7.000 IOP/s
>>>
>>>> if you launch 2 parallel fio, on same guest (on differents disk), do you get more iops ? (for me, it doesn't scale, so raid0 in guest doesn't help).
>>> No it doesn't scale.
>>>
>>> Stefan
>>>
>>>> ----- Mail original -----
>>>>
>>>> De: "Stefan Priebe" <s.priebe at profihost.ag>
>>>> À: "Alexandre DERUMIER" <aderumier at odiso.com>
>>>> Cc: "eric" <eric at netwalk.com>, pve-devel at pve.proxmox.com
>>>> Envoyé: Dimanche 11 Novembre 2012 13:07:36
>>>> Objet: Re: [pve-devel] less cores more iops / speed
>>>>
>>>> Am 11.11.2012 12:12, schrieb Alexandre DERUMIER:
>>>>> If I remember good, stefan can achieve 100.000 iops with iscsi with same kvm host.
>>>>
>>>> Correct but this was always with scsi-generic and I/O multipathing on
>>>> host. rbd does not support scsi-generic ;-(
>>>>
>>>>> I have checked ceph mailing, stefan seem to have resolved his problem with dual core with bios update !
>>>> Correct. So speed on Dual Xeon is now 14.000 IOP/s and 18.000 IOP/s on
>>>> Single Xeon. But the difference is an issue of the CPU Speed. 3,6Ghz
>>>> Single Xeon vs. 2.5Ghz Dual Xeon.
>>>>
>>>> Right now RBD in KVM is limited by CPU speed.
>>>>
>>>> Greets,
>>>> Stefan
>>>>
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