Commit bb34c453 authored by Chrysostomos Nanakos's avatar Chrysostomos Nanakos

docs: Update docs for 0.16

parent 6330d0b1
......@@ -650,27 +650,24 @@ Enabling this feature consists of the following steps:
.. _select_pithos_storage:
Select Pithos storage backend
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Starting from Synnefo 0.15.1 we introduce the ability to select or change the
storage backend. If you have already enabled and configured RADOS as your
secondary storage solution you can now explicitly select your storage
backend being only RADOS.
A new variable has been introduced called PITHOS_BACKEND_STORAGE with
possible values 'nfs' and 'rados', default value is 'nfs'.
For those users that need to migrate from NFS to RADOS and have not enabled the
dual mode of operation from the beginning of their installation, you can
use a synchronization script that is provided in order to synchronize the data
from NFS to Rados. The script can be found at
`/usr/lib/pithos/tools/pithos-sync-rados.sh`.
Since this version the dual mode of operation is not supported any more,
meaning you will not be able to keep double Pithos objects anymore in NFS and
RADOS.
After installing v0.15.1 you will have to choose between the storage backend
you want to use.
Pithos storage backend
~~~~~~~~~~~~~~~~~~~~~~
Starting from Synnefo version 0.16, we introduce Archipelago as the new storage
backend. Archipelago will act as a storage abstraction layer between Pithos and
NFS, RADOS or any other storage backend driver that Archipelago supports. For
more information about backend drivers please check Archipelago documentation.
Since this version care must be taken when restarting Archipelago on a Pithos
worker node. Pithos acts as an Archipelago peer and must be stopped first
before trying to restart Archipelago for any reason.
If you need to restart Archipelago on a running Pithos worker follow the
procedure below::
pithos-host$ /etc/init.d/gunicorn stop
pithos-host$ /etc/init.d/archipelago restart
pithos-host$ /etc/init.d/gunicorn start
Compute/Network/Image Service (Cyclades)
......
......@@ -17,33 +17,8 @@ make up the stored file in a Pithos container. After this consolidation the Pith
mapfile had to be converted to an Archipelago mapfile. An Archipelago mapfile
is an updated version of the Pithos mapfile, intended to supersede it.
Each Archipelago mapfile begins with a header, in big endian format, as
follows:
More info about the new mapfile you can find in Archipelago documentation.
::
struct ArchipelagoHeader {
uint32_t signature;
uint32_t version;
uint64_t size;
uint32_t blocksize;
uint32_t flags;
uint32_t epoch;
};
* The first 4 bytes contain the characters 'A', 'M', 'F', '.'.
* The next 4 bytes contain the format version used by the mapfile. Currently,
there has been two versions of the format, version 1 and version 2. Pithos
mapfiles wheren't following any specific mapfile header format until now.
* The next 8 bytes contain the size, in bytes, of the file represented by the
mapfile.
* The blocksize field gives the block size used by the storage backend.
* The value of the flags field is a mask of flags used to denote access
permissions to and properties of this mapfile.
* The epoch field is an index number used as a reference counter.
The list of hashes that make up the stored file is saved now, directly after
the mapfile header.
Upgrade Steps
=============
......
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