openstack team mailing list archive

[Lorin Hochstein <lorin@xxxxxxxxxxxxxxxxxx>]

This is good info, I submitted a doc patch to capture this in the Swift
admin guide: https://review.openstack.org/19046

Lorin


On Fri, Jan 4, 2013 at 1:27 PM, John Dickinson <me@xxxxxx> wrote:

> It's pretty simple. Swift uses the underlying filesystem to store the data
> on disk, and so you can use normal FS tools to find and inspect your data.
>
> For the object server, the "magic" happens here:
> https://github.com/openstack/swift/blob/master/swift/obj/server.py#L117
>
> The end result is that the data is stored here:
>
> /path/to/mount/points/device/objects/partition/hash_suffix/hash/
>
> That directory is the object. Inside the directory, there is normally just
> one file (named <timestamp>.data). The object's data is stored in the file,
> and the object's metadata is stored in the xattrs of the file.
>
> In some cases (mostly around failure handling), there may be more than one
> file in that directory, but for the general case, all the .data files are
> sorted (by filename) and the last is chosen (ie the most recent). As I
> said, there is normally just the one file in there.
>
> If you delete the object, the .data file is deleted and a <timestamp>.ts
> ("ts" for "tombstone") file is created as a zero-byte file. This is a
> delete marker that will be eventually reaped, but it exists to ensure that
> the delete properly propagates to all replicas in the cluster.
>
> --John
>
>
>
> On Jan 4, 2013, at 10:14 AM, "Snider, Tim" <Tim.Snider@xxxxxxxxxx> wrote:
>
> > I’d like to understand more on how Swift lays out objects on the
> underlaying storage. I can’t seem to find out  much about this in the
> openstack / swift documentation itself or in associated web searchs.
> > Thanks for pointers / links.
> > Tim
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-- 
Lorin Hochstein
Lead Architect - Cloud Services
Nimbis Services, Inc.
www.nimbisservices.com