gocept.zeoraid 1.0b4

The RAID storage

The ZEORaid storage is a proxy storage that works like a RAID controller by creating a redundant array of ZEO servers. The redundancy is similar to RAID level 1.

Therefore, up to N-1 out of N ZEO servers can fail without interrupting the service.

It is intended that any storage can be used as a backend storage for a RAID storage, although typically a ClientStorage will be the direct backend.

The ZEORaid server

The RAID storage could (in theory) be used directly from a Zope server. However, to achieve real reliability, the RAID has to run as a storage for multiple Zope servers, like a normal ZEO setup does.

For this, we leverage the normal ZEO server implementation and simply use a RAID storage instead of a FileStorage. To achieve full reliability, you can install multiple ZEORaid servers with identical configuration:

[ Zope 1 ]                      [ ZEORaid 1 ]                  [ ZEO 1 ]
[ Zope 2 ]    talk to all -->   [ ZEORaid 2 ]   talk to all -> [ ZEO 2 ]
...                             ...                            ...
[ Zope N]                       [ ZEORaid N ]                  [ ZEO N ]

ZEO RAID servers maintain a list of all the optimal, degraded and recovering storages and provide an extended Storage API to allow querying the RAID status and disabling and recovering storages at runtime.

Development

A mailing list is available at zeoraid@lists.gocept.com. Send an email with the subject subscribe to this address to join the list.

A bug tracker is available at launchpad: https://bugs.launchpad.net/gocept.zeoraid/