Re: [ceph-users] Question on RGW MULTISITE and librados

[Paul Nimbley]

That’s what we inferred from reading but wanted to be sure the replication was 
occurring at the RGW layer and not the RADOS layer.  We haven't yet had a 
chance to test out multisite since we only have a single test cluster set up at 
the moment.  On the topic of rgw multisite if I can ask a few more questions.  
Is there information available anywhere as to how the functionality handles WAN 
latency and throughput?  Is there a way to configure throttling on the data 
replication?  Also is there any way to tell when objects/pools are in sync 
between two clusters/zones?

Thanks,
Paul

-Original Message-
From: Yehuda Sadeh-Weinraub [mailto:yeh...@redhat.com] 
Sent: Friday, September 23, 2016 10:44 AM
To: Paul Nimbley <paul.nimb...@infinite.com>
Cc: ceph-users@lists.ceph.com
Subject: Re: [ceph-users] Question on RGW MULTISITE and librados

On Thu, Sep 22, 2016 at 1:52 PM, Paul Nimbley <paul.nimb...@infinite.com> wrote:
> Fairly new to ceph so please excuse any misused terminology.  We’re 
> currently exploring the use of ceph as a replacement storage backend 
> for an existing application.  The existing application has 2 
> requirements which seemingly can be met individually by using librados 
> and the Ceph Object Gateway multisite support, but it seems cannot be met 
> together.  These are:
>
>
>
> 1.   The ability to append to an existing object and read from any
> offset/length within the object, (the librados API allows this, the S3 
> and Swift APIs do not appear to support this).
>
> 2.   The ability to replicate data between 2 geographically separate
> locations.  I.e. 2 separate ceph clusters using the multisite support 
> of the Ceph Object Gateway to replicate between them.
>
>
>
> Specifically we’re testing using librados to write directly to the 
> object store because we need the ability to append to objects, which 
> using the librados API allows.  However if one writes to the object 
> store directly using the librados API is it correct to assume that 
> those objects will not be replicated to the other zone by the Ceph 
> Object Gateway since its being taken out of the data path?
>

The rgw multisite feature is an rgw only feature, and as such it doesn't apply 
to raw rados object operations. The rados gateway only handles its own data's 
replication, and it depends on its internal data structures and its different 
mechanics, so for raw rados replication there needs to be a different system in 
place.

Yehuda

>
>
> Thanks,
>
> Paul
>
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Re: [ceph-users] Question on RGW MULTISITE and librados

[Yehuda Sadeh-Weinraub]

On Thu, Sep 22, 2016 at 1:52 PM, Paul Nimbley  wrote:
> Fairly new to ceph so please excuse any misused terminology.  We’re
> currently exploring the use of ceph as a replacement storage backend for an
> existing application.  The existing application has 2 requirements which
> seemingly can be met individually by using librados and the Ceph Object
> Gateway multisite support, but it seems cannot be met together.  These are:
>
>
>
> 1.   The ability to append to an existing object and read from any
> offset/length within the object, (the librados API allows this, the S3 and
> Swift APIs do not appear to support this).
>
> 2.   The ability to replicate data between 2 geographically separate
> locations.  I.e. 2 separate ceph clusters using the multisite support of the
> Ceph Object Gateway to replicate between them.
>
>
>
> Specifically we’re testing using librados to write directly to the object
> store because we need the ability to append to objects, which using the
> librados API allows.  However if one writes to the object store directly
> using the librados API is it correct to assume that those objects will not
> be replicated to the other zone by the Ceph Object Gateway since its being
> taken out of the data path?
>

The rgw multisite feature is an rgw only feature, and as such it
doesn't apply to raw rados object operations. The rados gateway only
handles its own data's replication, and it depends on its internal
data structures and its different mechanics, so for raw rados
replication there needs to be a different system in place.

Yehuda

>
>
> Thanks,
>
> Paul
>
> This e-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION intended solely
> for the use of the addressee(s).
> If you are not the intended recipient, please notify so to the sender by
> e-mail and delete the original message.
> In such cases, please notify us immediately at i...@infinite.com . Further,
> you are not to copy,
> disclose, or distribute this e-mail or its contents to any unauthorized
> person(s) .Any such actions are
> considered unlawful. This e-mail may contain viruses. Infinite has taken
> every reasonable precaution to minimize
> this risk, but is not liable for any damage you may sustain as a result of
> any virus in this e-mail. You should
> carry out your own virus checks before opening the e-mail or attachments.
> Infinite reserves the right to monitor
> and review the content of all messages sent to or from this e-mail address.
> Messages sent to or from this e-mail
> address may be stored on the Infinite e-mail system.
> ***INFINITE End of DisclaimerINFINITE
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[ceph-users] Question on RGW MULTISITE and librados

[Paul Nimbley]

Fairly new to ceph so please excuse any misused terminology.  We're currently 
exploring the use of ceph as a replacement storage backend for an existing 
application.  The existing application has 2 requirements which seemingly can 
be met individually by using librados and the Ceph Object Gateway multisite 
support, but it seems cannot be met together.  These are:


1.   The ability to append to an existing object and read from any 
offset/length within the object, (the librados API allows this, the S3 and 
Swift APIs do not appear to support this).

2.   The ability to replicate data between 2 geographically separate 
locations.  I.e. 2 separate ceph clusters using the multisite support of the 
Ceph Object Gateway to replicate between them.

Specifically we're testing using librados to write directly to the object store 
because we need the ability to append to objects, which using the librados API 
allows.  However if one writes to the object store directly using the librados 
API is it correct to assume that those objects will not be replicated to the 
other zone by the Ceph Object Gateway since its being taken out of the data 
path?

Thanks,
Paul
This e-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION intended solely 
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and delete the original message.

In such cases, please notify us immediately at i...@infinite.com . Further, you 
are not to copy, 

disclose, or distribute this e-mail or its contents to any unauthorized 
person(s) .Any such actions are 

considered unlawful. This e-mail may contain viruses. Infinite has taken every 
reasonable precaution to minimize

this risk, but is not liable for any damage you may sustain as a result of any 
virus in this e-mail. You should 

carry out your own virus checks before opening the e-mail or attachments. 
Infinite reserves the right to monitor

and review the content of all messages sent to or from this e-mail address. 
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