Warning: This document is for the development version of Bareos Documentation. The main version is bareos-18.2.

Storage Backends

A Bareos Storage Daemon can use various storage backends:

Tape
is used to access tape device and thus has sequential access.
File
tells Bareos that the device is a file. It may either be a file defined on fixed medium or a removable filesystem such as USB. All files must be random access devices.
Fifo
is a first-in-first-out sequential access read-only or write-only device.
Droplet
is used to access an object store supported by libdroplet, most notably S3. For details, refer to Droplet Storage Backend.
GFAPI (GlusterFS)
is used to access a GlusterFS storage.
Rados (Ceph Object Store)
is used to access a Ceph object store.

Droplet Storage Backend

The bareos-storage-droplet backend (Version >= 17.2.7) can be used to access Object Storage through libdroplet. Droplet support a number of backends, most notably S3. For details about Droplet itself see https://github.com/scality/Droplet.

Requirements

  • The Bareos package bareos-storage-droplet is not available on all platforms. Please refer to Packages for the different Linux platforms.
  • Droplet S3:
    • The droplet S3 backend can only be used with virtual-hosted-style buckets like http://bucket.s3_server/object. Path-style buckets are not supported. It has been tested successfully with AWS S3 and CEPH Object Gateway S3.

Installation

Install the package bareos-storage-droplet by using an appropriate package management tool (eg. yum, zypper).

Configuration

The droplet backend requires a Bareos Director Storage Resource, a Bareos Storage Daemon Device Resource as well as a Droplet profile file where your access– and secret–keys and other parameters for the connection to your object storage are stored.

AWS S3

Director

First, we will create the new Bareos Director Storage Resource.

For the following example, we

  • choose the name S3_Object (Dir->Storage).
  • choose Media Type (Dir->Storage) = S3_Object1. We name it this way, in case we later add more separated Object Storages that don’t have access to the same volumes.
  • assume the Bareos Storage Daemon is located on the host bareos-sd.example.com and will offers the Device Resource S3_ObjectStorage (Sd->Device) (to be configured in the next section).
bareos-dir.d/storage/S3_Object.conf
Storage {
    Name = "S3_Object"
    Address  = "bareos-sd.example.com"
    Password = "secret"
    Device = "AWS_S3_1-00"
    Media Type = "S3_Object1"
}

These credentials are only used to connect to the Bareos Storage Daemon. The credentials to access the object store (e.g. S3) are stored in the Bareos Storage Daemon Droplet Profile.

Storage Daemon

As of your Bareos Storage Daemon configuration, we need to setup a new device that acts as a link to Object Storage backend.

The name and media type must correspond to those settings in the Bareos Director Storage Resource:

A device for the usage of AWS S3 object storage with a bucket named backup-bareos located in EU Central 1 (Frankfurt, Germany), would look like this:

bareos-sd.d/device/AWS_S3_1-00.conf
Device {
  Name = "AWS_S3_1-00"
  Media Type = "S3_Object1"
  Archive Device = "AWS S3 Storage"
  Device Type = droplet
  Device Options = "profile=/etc/bareos/bareos-sd.d/device/droplet/aws.profile,bucket=backup-bareos,chunksize=100M"
  Label Media = yes                    # Lets Bareos label unlabeled media
  Random Access = yes
  Automatic Mount = yes                # When device opened, read it
  Removable Media = no
  Always Open = no
  Maximum Concurrent Jobs = 1
}

In these examples all the backup data is placed in the bareos-backup bucket on the defined S3 storage. In contrast to other Bareos Storage Daemon backends, a Bareos volume is not represented by a single file. Instead a volume is a sub-directory in the defined bucket and every chunk is placed in the volume directory with the filename 0000-9999 and a size defined in the chunksize option. It is implemented this way, as S3 does not allow to append to a file. Instead it always writes full files, so every append operation could result in reading and writing the full volume file.

Following Device Options (Sd->Device) settings are possible:

profile
Droplet profile path (e.g. /etc/bareos/bareos-sd.d/device/droplet/droplet.profile). Make sure the profile file is readable for user bareos.
acl
Canned ACL
storageclass
Storage Class to use.
bucket
Bucket to store objects in.
chunksize
Size of Volume Chunks (default = 10 Mb).
iothreads
Number of IO-threads to use for uploads (if not set, blocking uploads are used)
ioslots
Number of IO-slots per IO-thread (0-255, default 10). Set this to values greater than 1 for cached and to 0 for direct writing.
retries
Number of writing tries before discarding the data. Set this to 0 for unlimited retries. Setting anything != 0 here will cause dataloss if the backend is not available, so be very careful (0-255, default = 0, which means unlimited retries).
mmap
Use mmap to allocate Chunk memory instead of malloc().
location
Deprecated. If required (AWS only), it has to be set in the Droplet profile.

Create the Droplet profile to be used. This profile is used later by the droplet library when accessing your cloud storage.

An example for AWS S3 could look like this:

aws.profile
host = s3.amazonaws.com         # This parameter is only used as baseurl and will be prepended with bucket and location set in device ressource to form correct url
use_https = true
access_key = myaccesskey
secret_key = mysecretkey
pricing_dir = ""                # If not empty, an droplet.csv file will be created which will record all S3 operations.
backend = s3
aws_auth_sign_version = 4       # Currently, AWS S3 uses version 4. The Ceph S3 gateway uses version 2.
aws_region = eu-central-1

More arguments and the SSL parameters can be found in the documentation of the droplet library: externalReferenceDropletDocConfigurationFile

CEPH Object Gateway S3

Please note, that there is also the Rados Storage Backend backend, which can backup to CEPH directly. However, currently (17.2.7) the Droplet (S3) is known to outperform the Rados backend.

While parameters have been explained in the AWS S3 section, this gives an example about how to backup to a CEPH Object Gateway S3.

bareos-dir.d/storage/S3_Object.conf
Storage {
    Name = "S3_Object"
    Address  = "bareos-sd.example.com"
    Password = "secret"
    Device = "CEPH_1-00"
    Media Type = "S3_Object1"
}

A device for CEPH object storage could look like this:

bareos-sd.d/device/CEPH_1-00.conf
Device {
  Name = "CEPH_1-00"
  Media Type = "S3_Object1"
  Archive Device = "Object S3 Storage"
  Device Type = droplet
  Device Options = "profile=/etc/bareos/bareos-sd.d/droplet/ceph-rados-gateway.profile,bucket=backup-bareos,chunksize=100M"
  Label Media = yes                    # Lets Bareos label unlabeled media
  Random Access = yes
  Automatic Mount = yes                # When device opened, read it
  Removable Media = no
  Always Open = no
  Maximum Concurrent Jobs = 1
}

The correspondig Droplet profile looks like this:

ceph-rados-gateway.profile
host = CEPH-host.example.com
use_https = False
access_key = myaccesskey
secret_key = mysecretkey
pricing_dir = ""
backend = s3
aws_auth_sign_version = 2

Main differences are, that aws_region is not required and aws_auth_sign_version = 2 instead of 4.

Troubleshooting

iothreads

For testing following Device Options (Sd->Device) should be used:

  • iothreads=0
  • retries=1

If the S3 backend is or becomes unreachable, the Bareos Storage Daemon will behave depending on iothreads and retries. When the Bareos Storage Daemon is using cached writing (iothreads >=1) and retries is set to zero (unlimited tries), the job will continue running until the backend becomes available again. The job cannot be canceled in this case, as the Bareos Storage Daemon will continuously try to write the cached files.

Great caution should be used when using retries>=0 combined with cached writing. If the backend becomes unavailable and the Bareos Storage Daemon reaches the predefined tries, the job will be discarded silently yet marked as OK in the Bareos Director.

You can always check the status of the writing process by using status storage=…. The current writing status will be displayed then:

status storage
...
Device "S3_ObjectStorage" (S3) is mounted with:
    Volume:      Full-0085
    Pool:        Full
    Media type:  S3_Object1
Backend connection is working.
Inflight chunks: 2
Pending IO flush requests:
   /Full-0085/0002 - 10485760 (try=0)
   /Full-0085/0003 - 10485760 (try=0)
   /Full-0085/0004 - 10485760 (try=0)
...
Attached Jobs: 175
...

Pending IO flush requests means that there is data to be written. try`=0 means that this is the first try and no problem has occurred. If :strong:`try >0, problems occurred and the storage daemon will continue trying.

Status without pending IO chunks:

status storage
...
Device "S3_ObjectStorage" (S3) is mounted with:
    Volume:      Full-0084
    Pool:        Full
    Media type:  S3_Object1
Backend connection is working.
No Pending IO flush requests.
Configured device capabilities:
  EOF BSR BSF FSR FSF EOM !REM RACCESS AUTOMOUNT LABEL !ANONVOLS !ALWAYSOPEN
Device state:
  OPENED !TAPE LABEL !MALLOC APPEND !READ EOT !WEOT !EOF !NEXTVOL !SHORT MOUNTED
  num_writers=0 reserves=0 block=8
Attached Jobs:
...

For performance, Device Options (Sd->Device) should be configured with:

  • iothreads >= 1
  • retries = 0

New AWS S3 Buckets

As AWS S3 buckets are accessed via virtual-hosted-style buckets (like http://bucket.s3_server/object) creating a new bucket results in a new DNS entry.

As a new DNS entry is not available immediatly, Amazon solves this by using HTTP temporary redirects (code: 307) to redirect to the correct host. Unfortenatly, the Droplet library does not support HTTP redirects.

Requesting the device status only resturn a unspecific error:

status storage
*status storage=...
...
Backend connection is not working.
...
Workaround:
  • Wait until bucket is available a permanet hostname. This can take up to 24 hours.

  • Configure the AWS location into the profiles host entry. For the AWS location eu-central-1, change host = s3.amazonaws.com into host = s3.eu-central-1.amazonaws.com:

    Droplet profile
    ...
    host = s3.eu-central-1.amazonaws.com
    aws_region = eu-central-1
    ...
    

AWS S3 Logging

If you use AWS S3 object storage and want to debug your bareos setup, it is recommended to turn on the server access logging in your bucket properties. You will see if bareos gets to try writing into your bucket or not.

GFAPI Storage Backend

GFAPI (GlusterFS)

A GlusterFS Storage can be used as Storage backend of Bareos. Prerequistes are a working GlusterFS storage system and the package bareos-storage-glusterfs. See http://www.gluster.org/ for more information regarding GlusterFS installation and configuration and specifically https://gluster.readthedocs.org/en/latest/Administrator Guide/Bareos/ for Bareos integration. You can use following snippet to configure it as storage device:

Device {
  Name = GlusterStorage
  Archive Device = "Gluster Device"
  Device Options = "uri=gluster://server.example.com/volumename/bareos"
  Device Type = gfapi
  Media Type = GlusterFile
  Label Media = yes
  Random Access = yes
  Automatic Mount = yes
  Removable Media = no
  Always Open = no
}

Adapt server and volume name to your environment.

Version >= 15.2.0

Rados Storage Backend

Rados (Ceph Object Store)

Here you configure the Ceph object store, which is accessed by the SD using the Rados library. Prerequistes are a working Ceph object store and the package bareos-storage-ceph. See http://ceph.com for more information regarding Ceph installation and configuration. Assuming that you have an object store with name poolname and your Ceph access is configured in /etc/ceph/ceph.conf, you can use following snippet to configure it as storage device:

Device {
  Name = RadosStorage
  Archive Device = "Rados Device"
  Device Options = "conffile=/etc/ceph/ceph.conf,poolname=poolname"
  Device Type = rados
  Media Type = RadosFile
  Label Media = yes
  Random Access = yes
  Automatic Mount = yes
  Removable Media = no
  Always Open = no
}

Version >= 15.2.0