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Swift: NAS or DAS?

 

 

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michael.vandeborne at cetic

Mar 16, 2012, 6:32 AM

Post #1 of 9 (247 views)
Permalink
Swift: NAS or DAS?

Hi all,

on the very useful www.referencearchitecture.org website, and in every
piece of documentation on Swift, I never found anything like a NAS
attached to a storage node. It was all about DAS solution.
Is there a specific reason why a NAS wouldn't be a good choice to build
a swift infrastructure?

thank you


--
MichaŽl Van de Borne
R&D Engineer, SOA team, CETIC
Phone: +32 (0)71 49 07 45 Mobile: +32 (0)472 69 57 16, Skype: mikemowgli
www.cetic.be, rue des FrŤres Wright, 29/3, B-6041 Charleroi


me at not

Mar 16, 2012, 6:38 AM

Post #2 of 9 (256 views)
Permalink
Re: Swift: NAS or DAS? [In reply to]

Generally, you would introduce latency in the storage system by using a NAS attached to a storage drive. Also, at scale, your costs will be dominated by drive, so you will want to optimize the storage nodes for dense, cheap storage.

--John


On Mar 16, 2012, at 8:32 AM, MichaŽl Van de Borne wrote:

> Hi all,
>
> on the very useful www.referencearchitecture.org website, and in every piece of documentation on Swift, I never found anything like a NAS attached to a storage node. It was all about DAS solution.
> Is there a specific reason why a NAS wouldn't be a good choice to build a swift infrastructure?
>
> thank you
>
>
> --
> MichaŽl Van de Borne
> R&D Engineer, SOA team, CETIC
> Phone: +32 (0)71 49 07 45 Mobile: +32 (0)472 69 57 16, Skype: mikemowgli
> www.cetic.be, rue des FrŤres Wright, 29/3, B-6041 Charleroi
>
>
> _______________________________________________
> Mailing list: https://launchpad.net/~openstack
> Post to : openstack [at] lists
> Unsubscribe : https://launchpad.net/~openstack
> More help : https://help.launchpad.net/ListHelp
Attachments: smime.p7s (4.23 KB)


gavin.brebner at hp

Mar 16, 2012, 6:47 AM

Post #3 of 9 (244 views)
Permalink
Re: Swift: NAS or DAS? [In reply to]

Price ! Why provide expensive redundant storage when cheap disks
will do just as well ?

Gavin

> -----Original Message-----
> From: openstack-bounces+gavin.brebner=hp.com [at] lists
> [mailto:openstack-bounces+gavin.brebner=hp.com [at] lists]
> On Behalf Of MichaŽl Van de Borne
> Sent: Friday, March 16, 2012 2:33 PM
> To: openstack [at] lists
> Subject: [Openstack] Swift: NAS or DAS?
>
> Hi all,
>
> on the very useful www.referencearchitecture.org website, and in every
> piece of documentation on Swift, I never found anything like a NAS
> attached to a storage node. It was all about DAS solution.
> Is there a specific reason why a NAS wouldn't be a good choice to build a
> swift infrastructure?
>
> thank you
>
>
> --
> MichaŽl Van de Borne
> R&D Engineer, SOA team, CETIC
> Phone: +32 (0)71 49 07 45 Mobile: +32 (0)472 69 57 16, Skype: mikemowgli
> www.cetic.be, rue des FrŤres Wright, 29/3, B-6041 Charleroi
>
>
> _______________________________________________
> Mailing list: https://launchpad.net/~openstack
> Post to : openstack [at] lists
> Unsubscribe : https://launchpad.net/~openstack
> More help : https://help.launchpad.net/ListHelp


frederik at cluttr

Mar 16, 2012, 6:48 AM

Post #4 of 9 (251 views)
Permalink
Re: Swift: NAS or DAS? [In reply to]

Hey Michael,

*Is there a specific reason why a NAS wouldn't be a good choice to build a
> swift infrastructure?*


Why would that make sense to you?

The idea of Swift is to distribute the files over a large amount of
"inexpensive" servers and prevent data loss by keeping multiple copies.
Whereas in a NAS you typically have fat servers with lots of disks with a
RAID on top of them to take care of the data loss.

Using NAS underneath Swift would therefore in my opinion make no sense at
all. On the other hand, using Swift as a building block for a NAS system
would. (although that would require a file system, since Swift is purely
object based).



Kind regards,
Frederik Van Hecke

*T:* +32487733713
*E:* frederik [at] cluttr
*W:* www.cluttr.be



*This e-mail and any attachments thereto may contain information which
is confidential and/or protected by intellectual property rights and
are intended for the sole use of the recipient(s)named above. Any use
of the information contained herein (including, but not limited to,
total or partial reproduction, communication or distribution in any
form) by persons other than the designated recipient(s) is prohibited.
If you have received this e-mail in error, please notify the sender
either by telephone or by e-mail and delete the material from any
computer. Thank you for your cooperation.*




On Fri, Mar 16, 2012 at 14:32, MichaŽl Van de Borne <
michael.vandeborne [at] cetic> wrote:

> Hi all,
>
> on the very useful www.referencearchitecture.org website, and in every
> piece of documentation on Swift, I never found anything like a NAS attached
> to a storage node. It was all about DAS solution.
> Is there a specific reason why a NAS wouldn't be a good choice to build a
> swift infrastructure?
>
> thank you
>
>
> --
> MichaŽl Van de Borne
> R&D Engineer, SOA team, CETIC
> Phone: +32 (0)71 49 07 45 Mobile: +32 (0)472 69 57 16, Skype: mikemowgli
> www.cetic.be, rue des FrŤres Wright, 29/3, B-6041 Charleroi
>
>
> ______________________________**_________________
> Mailing list: https://launchpad.net/~**openstack<https://launchpad.net/~openstack>
> Post to : openstack [at] lists
> Unsubscribe : https://launchpad.net/~**openstack<https://launchpad.net/~openstack>
> More help : https://help.launchpad.net/**ListHelp<https://help.launchpad.net/ListHelp>
>


pauloricardomg at gmail

Mar 16, 2012, 7:21 AM

Post #5 of 9 (246 views)
Permalink
Re: Swift: NAS or DAS? [In reply to]

I don't think anything prevents integrating Swift storage nodes with a NAS.
Latency could be increased but depending on load, network capacity (shared
vs dedicated), and use of caching, it is possible to achieve a good
performance.

This link shows the integration of NexentaStor (a NAS/SAN integrated
storage solution) with Openstack Nova:
http://mirantis.blogspot.com/2011/11/converging-openstack-with-nexenta.html

2012/3/16 John Dickinson <me [at] not>

> Generally, you would introduce latency in the storage system by using a
> NAS attached to a storage drive. Also, at scale, your costs will be
> dominated by drive, so you will want to optimize the storage nodes for
> dense, cheap storage.
>
> --John
>
>
> On Mar 16, 2012, at 8:32 AM, MichaŽl Van de Borne wrote:
>
> > Hi all,
> >
> > on the very useful www.referencearchitecture.org website, and in every
> piece of documentation on Swift, I never found anything like a NAS attached
> to a storage node. It was all about DAS solution.
> > Is there a specific reason why a NAS wouldn't be a good choice to build
> a swift infrastructure?
> >
> > thank you
> >
> >
> > --
> > MichaŽl Van de Borne
> > R&D Engineer, SOA team, CETIC
> > Phone: +32 (0)71 49 07 45 Mobile: +32 (0)472 69 57 16, Skype: mikemowgli
> > www.cetic.be, rue des FrŤres Wright, 29/3, B-6041 Charleroi
> >
> >
> > _______________________________________________
> > Mailing list: https://launchpad.net/~openstack
> > Post to : openstack [at] lists
> > Unsubscribe : https://launchpad.net/~openstack
> > More help : https://help.launchpad.net/ListHelp
>
>
> _______________________________________________
> Mailing list: https://launchpad.net/~openstack
> Post to : openstack [at] lists
> Unsubscribe : https://launchpad.net/~openstack
> More help : https://help.launchpad.net/ListHelp
>
>


--
Paulo Ricardo

--
European Master in Distributed Computing***
Royal Institute of Technology - KTH
*
*Instituto Superior Tťcnico - IST*
*http://paulormg.com*


frederik at cluttr

Mar 16, 2012, 8:44 AM

Post #6 of 9 (248 views)
Permalink
Re: Swift: NAS or DAS? [In reply to]

Paulo,



> *I don't think anything prevents integrating Swift storage nodes with a
> NAS. Latency could be increased but depending on load, network capacity
> (shared vs dedicated), and use of caching, it is possible to achieve a good
> performance.*


Yes, but why would you do so..

Using NAS as storage target for Swift will as said increase the CAPEX price
and latency. And instead of 1 layer you'll have to 2 layers to manage and
maintain, which will increase operating cost. The only reason I can think
of why you might consider this is if you have a shitload of NAS systems in
your DC that you don't want to throw out the door just yet..

They both address the same problem (file storage) through a different
approach. NAS is practical for users, with NFS support built into
practically every OS. But there's a reason why we just don't stick to NAS
systems, they're expensive and hard to scale.

Using NAS as building block of Swift would take away the ease of use for
the user that NFS gives them (and what they're familiar with) but would
still leave you with all the problems at the operational side of the story.
Even worse, it would make it even more expensive and complicated.



*This link shows the integration of NexentaStor (a NAS/SAN integrated
> storage solution) with Openstack Nova:
> http://mirantis.blogspot.com/2011/11/converging-openstack-with-nexenta.html
> *



That's Nova, not Swift..
In case of Nova, a NAS or SAN approach makes very much sense.



Kind regards,
Frederik Van Hecke

*T:* +32487733713
*E:* frederik [at] cluttr
*W:* www.cluttr.be



*This e-mail and any attachments thereto may contain information which
is confidential and/or protected by intellectual property rights and
are intended for the sole use of the recipient(s)named above. Any use
of the information contained herein (including, but not limited to,
total or partial reproduction, communication or distribution in any
form) by persons other than the designated recipient(s) is prohibited.
If you have received this e-mail in error, please notify the sender
either by telephone or by e-mail and delete the material from any
computer. Thank you for your cooperation.*




On Fri, Mar 16, 2012 at 15:21, Paulo Ricardo Motta Gomes <
pauloricardomg [at] gmail> wrote:

> I don't think anything prevents integrating Swift storage nodes with a
> NAS. Latency could be increased but depending on load, network capacity
> (shared vs dedicated), and use of caching, it is possible to achieve a good
> performance.
>
> This link shows the integration of NexentaStor (a NAS/SAN integrated
> storage solution) with Openstack Nova:
> http://mirantis.blogspot.com/2011/11/converging-openstack-with-nexenta.html
>
> 2012/3/16 John Dickinson <me [at] not>
>
>> Generally, you would introduce latency in the storage system by using a
>> NAS attached to a storage drive. Also, at scale, your costs will be
>> dominated by drive, so you will want to optimize the storage nodes for
>> dense, cheap storage.
>>
>> --John
>>
>>
>> On Mar 16, 2012, at 8:32 AM, MichaŽl Van de Borne wrote:
>>
>> > Hi all,
>> >
>> > on the very useful www.referencearchitecture.org website, and in every
>> piece of documentation on Swift, I never found anything like a NAS attached
>> to a storage node. It was all about DAS solution.
>> > Is there a specific reason why a NAS wouldn't be a good choice to build
>> a swift infrastructure?
>> >
>> > thank you
>> >
>> >
>> > --
>> > MichaŽl Van de Borne
>> > R&D Engineer, SOA team, CETIC
>> > Phone: +32 (0)71 49 07 45 Mobile: +32 (0)472 69 57 16, Skype:
>> mikemowgli
>> > www.cetic.be, rue des FrŤres Wright, 29/3, B-6041 Charleroi
>> >
>> >
>> > _______________________________________________
>> > Mailing list: https://launchpad.net/~openstack
>> > Post to : openstack [at] lists
>> > Unsubscribe : https://launchpad.net/~openstack
>> > More help : https://help.launchpad.net/ListHelp
>>
>>
>> _______________________________________________
>> Mailing list: https://launchpad.net/~openstack
>> Post to : openstack [at] lists
>> Unsubscribe : https://launchpad.net/~openstack
>> More help : https://help.launchpad.net/ListHelp
>>
>>
>
>
> --
> Paulo Ricardo
>
> --
> European Master in Distributed Computing***
> Royal Institute of Technology - KTH
> *
> *Instituto Superior Tťcnico - IST*
> *http://paulormg.com*
>
>
> _______________________________________________
> Mailing list: https://launchpad.net/~openstack
> Post to : openstack [at] lists
> Unsubscribe : https://launchpad.net/~openstack
> More help : https://help.launchpad.net/ListHelp
>
>


acs at parvuscaptus

Mar 16, 2012, 9:13 AM

Post #7 of 9 (246 views)
Permalink
Re: Swift: NAS or DAS? [In reply to]

>
>
> *This link shows the integration of NexentaStor (a NAS/SAN integrated
>> storage solution) with Openstack Nova:
>> http://mirantis.blogspot.com/2011/11/converging-openstack-with-nexenta.html
>> *
>
>
>
> That's Nova, not Swift..
> In case of Nova, a NAS or SAN approach makes very much sense.
>

Running swift on a NAS is all downside. You can make it work, but I don't
see any benefit.

As an aside, above a moderate scale, NAS can start to get problematic for
Nova volumes as well, depending on the architecture and usage patterns.

Nexenta is productized ZFS. You could set up something similar providing
iscsi from other systems that support ZFS.


Caitlin.Bestler at nexenta

Mar 16, 2012, 11:05 AM

Post #8 of 9 (252 views)
Permalink
Re: Swift: NAS or DAS? [In reply to]

There are numerous reasons why you would want your Swift Object Server to also host a NAS server.

But whether you are talking Nova volumes or Swift Objects, you would generally want the Volume Server
or Object Server to access those "directly" rather than via NAS over a general network connection.

There are a lot of trade-offs however. Realistically large JBOD arrays are not truly "direct attached", they
Are being accessed over a FC or SAS network. Currently SAS is a more cost effective method of connecting
A server with a large number of targets. 10 GbE networking might slightly outperform SAS, but the cost
per port is higher.

In addition to the connectivity issues, you would generally want to avoid adding an extra layer of name
Resolution before you reached your real data.


Caitlin.Bestler at nexenta

Mar 16, 2012, 12:01 PM

Post #9 of 9 (246 views)
Permalink
Re: Swift: NAS or DAS? [In reply to]

Brebner, Gavin asked:

>Price ! Why provide expensive redundant storage when cheap disks will do just as well ?

Because you are interested in the total cost.

Using excessive network replication rather than local replication makes for a more expensive
And less robust solution -- as long as the local replication is of high enough quality.

Typical hardware RAID solutions are too stupid to be effective here. But replicas can be created
by file systems such as ZFS far more cost effectively than doing an extra network replica, and
still be just as independent and provide just as much protection from data loss.

See http://etherpad.openstack.org/YMTqYzPmZQ

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