v0.47 released

v0.47 released

[Sage Weil]

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It's been another three weeks and v0.47 is ready.  The highlights include:

 * mon: admin tools to control unwieldy clusters (temporarily block osd 
   boots, failures, etc.)
 * osd: reduced memory footprint for peering/thrashing
 * librbd: write-thru cache mode
 * librbd: improved error handling
 * osd: removal of ill-conceived 'localized pg' feature (those annoying 
   PGs with 'p' in them)
 * rados-bench: simple tool to benchmark radosgw (or S3) (based on 'rados 
   bench' command)

In truth it wasn't the most productive sprint because of the work that 
went into the launch of the web sites, the launch party, and the 
subsequent inebriation.  However, the new RBD caching feature is looking 
very good at this point, and patches are working their way upstream in 
Qemu/KVM to enable it with the generic 'cache=writethrough' or 
'cache=writeback' settings.

One other noteworthy item is that I generated a new PGP key to sign 
releases with.  The key is now in ceph.git, and has been signed by my 
personal key.  If you are installing debs from our repositories, you'll 
want to add the new key to your APT keyring to avoid annoying security 
warnings.

For v0.48, we are working on a ceph-osd refactor to improve threading and 
performance, multi-monitor and OSD hotplugging support for upstart and 
Chef, improvements to the OSD and monitor bootstrapping to make that 
possible, and RBD groundwork for the much-anticipated layering feature.

You can get v0.47 from the usual places:

 * Git at git://github.com/ceph/ceph.git
 * Tarball at http://ceph.newdream.net/download/ceph-0.47.tar.gz
 * For Debian/Ubuntu packages, see http://ceph.newdream.net/docs/master/install/debian

Re: v0.47 released

[Sage Weil]

On Sun, 20 May 2012, Sage Weil wrote:
>  * rados-bench: simple tool to benchmark radosgw (or S3) (based on 'rados 
>    bench' command)

Whoops, that's "rest-bench".  

sage

Re: v0.47 released

[Stefan Priebe - Profihost AG]

Hi,

the debian archive still shows: 0.46 =>
http://ceph.com/debian/dists/squeeze/main/binary-amd64/Packages

Greets
  Stefan

Am 21.05.2012 06:38, schrieb Sage Weil:
> It's been another three weeks and v0.47 is ready.  The highlights include:
> 
>  * mon: admin tools to control unwieldy clusters (temporarily block osd 
>    boots, failures, etc.)
>  * osd: reduced memory footprint for peering/thrashing
>  * librbd: write-thru cache mode
>  * librbd: improved error handling
>  * osd: removal of ill-conceived 'localized pg' feature (those annoying 
>    PGs with 'p' in them)
>  * rados-bench: simple tool to benchmark radosgw (or S3) (based on 'rados 
>    bench' command)
> 
> In truth it wasn't the most productive sprint because of the work that 
> went into the launch of the web sites, the launch party, and the 
> subsequent inebriation.  However, the new RBD caching feature is looking 
> very good at this point, and patches are working their way upstream in 
> Qemu/KVM to enable it with the generic 'cache=writethrough' or 
> 'cache=writeback' settings.
> 
> One other noteworthy item is that I generated a new PGP key to sign 
> releases with.  The key is now in ceph.git, and has been signed by my 
> personal key.  If you are installing debs from our repositories, you'll 
> want to add the new key to your APT keyring to avoid annoying security 
> warnings.
> 
> For v0.48, we are working on a ceph-osd refactor to improve threading and 
> performance, multi-monitor and OSD hotplugging support for upstart and 
> Chef, improvements to the OSD and monitor bootstrapping to make that 
> possible, and RBD groundwork for the much-anticipated layering feature.
> 
> You can get v0.47 from the usual places:
> 
>  * Git at git://github.com/ceph/ceph.git
>  * Tarball at http://ceph.newdream.net/download/ceph-0.47.tar.gz
>  * For Debian/Ubuntu packages, see http://ceph.newdream.net/docs/master/install/debian

Re: v0.47 released

[Josh Durgin]

On 05/20/2012 09:38 PM, Sage Weil wrote:
> It's been another three weeks and v0.47 is ready.  The highlights include:
>
>   * librbd: write-thru cache mode

Some more detail on rbd caching:

By default librbd does no caching - writes and reads go directly to the
storage cluster, and writes return only when the data is on disk on all
replicas.

With caching enabled, writes return immediately, unless there are more
than rbd_cache_max_dirty unflushed bytes. In this case, the write
triggers writeback and blocks until enough bytes are flushed.

To enable writethrough mode, set rbd_cache_max_dirty to 0. This means
writes return only when the data is on disk on all replicas, but reads
may come from the cache.

The cache is in memory on the client, and each rbd image has its own.
Since it's local to the client, and there's no coherency if there are
others accessing the image, running something like GFS or OCFS on top
of rbd would not work with caching enabled.

The options for controlling the cache are:

option                 | type      | default | description
-----------------------+-----------+---------+------------
rbd_cache              | bool      | false   | whether caching is enabled
rbd_cache_size         | long long | 32 MiB  | total cache size in bytes
rbd_cache_max_dirty    | long long | 24 MiB  | maximum number of dirty 
bytes before triggering writeback
rbd_cache_target_dirty | long long | 16 MiB  | writeback starts at this 
threshold, but does not block the write
rbd_cache_max_age      | float     | 1.0     | seconds in cache before 
writeback starts

The cache code was written for ceph-fuse a few years ago, so it's been
in use for a while now. It was just tweaked a bit to allow librbd
to use it. The rbd_cache_* options have the same meanings as the
client_oc_* options for ceph-fuse.

>   * librbd: improved error handling

To clarify, these were fixes for error handling in the caching module
used by ceph-fuse and librbd, and does not matter if you aren't using
ceph-fuse or rbd caching. It made write errors be returned to the
caller when the cache is flushed, and exposed read errors to the client
as well.

0.47 also includes a fix for a deadlock that was more likely to 
triggered with rbd caching enabled. I don't know of any outstanding 
issues with rbd caching since that was fixed.

Josh