ring creation

Asked by serious on 2013-11-04

I am wondering for a swift cluster, could I create rings with different power_part for account, container, and object.
We have SSD cards, we would like to use it for account and containers because these will be small amount of data,
however, we would like to use normal 3Tb and 4TB hard disks for objects because data files are way more.

swift-ring-builder account.builder create 14 3 1 # here use partition power_part =14
swift-ring-builder container.builder create 16 3 1 # power_part =16
swift-ring-builder object.builder create 18 3 1 # power_part =18

swift-ring-builder account.builder r1z1-192.168.1.100:6002/ssd1 # here use SSD
swift-ring-builder container.builder r1z1-192.168.1.100:6001/ssd2 # here use SSD
swift-ring-builder object.builder r1z1-192.168.1.100:6000/sdb1 # here use 3TB/4TB hard disks

will the above configuration feasible, make sense performance wise?

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Last query:
2013-11-04
Last reply:
2013-11-12
Samuel Merritt (torgomatic) said : #1

The part power is affected by the number of total disks, not their sizes, so the fact that your SSDs are smaller than your spinning disks is of no importance.

However, if you're planning to have fewer SSDs than spinning disks, then you can go ahead and use different part powers for the different rings.

serious (guanwen) said : #2

Will this way has any performance gain? Intuitively, it will. because
 1)small power_part for container/account consumes less memory. Look up might be faster
 2) SSD access is faster

However, I am wondering if there are any side effects (bad) when configure account and container
on separate faster SSD disks than object?

Please comment. Thanks

serious (guanwen) said : #3

Will this way has any performance gain? Intuitively, it will. because
 1)small power_part for container/account consumes less memory. Look up
might be faster
 2) SSD access is faster

However, I am wondering if there are any side effects (bad) when configure
account and container
on separate faster SSD disks than object?

Please comment. Thanks

Henry

On Mon, Nov 4, 2013 at 10:26 AM, Samuel Merritt <
<email address hidden>> wrote:

> Your question #238631 on OpenStack Object Storage (swift) changed:
> https://answers.launchpad.net/swift/+question/238631
>
> Status: Open => Answered
>
> Samuel Merritt proposed the following answer:
> The part power is affected by the number of total disks, not their
> sizes, so the fact that your SSDs are smaller than your spinning disks
> is of no importance.
>
> However, if you're planning to have fewer SSDs than spinning disks, then
> you can go ahead and use different part powers for the different rings.
>
> --
> If this answers your question, please go to the following page to let us
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Marcelo Martins (btorch) said : #4

Hi Serious,

No you should not have any bad side effects. In fact that has been one of the strategies to avoid async-pendings when that becomes a problem for heavily used systems. So it's perfectly fine to dedicate SSDs to account/container storage within a storage node or even have separate account/container servers with SSDs for that purpose.

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