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This article explains how to setup Parallels Cloud '''Virtuozzo Storage cluster ''' is a highly-available distributed storage (virtual SAN) with built-in replication and deploy ploop-based OpenVZ container inside the clusterdisaster recovery.

==Setting up Parallels Cloud Virtuozzo Storage provides a storage virtualization platform on top of commodity hardware with locally attached hard drives and enables the unification of storage into a cluster==in scenarios like virtualization with the help of virtual machines (VMs) and/or Containers ([[CT]]s). Pstorage ensures a fast live migration of VMs and CTs across hardware nodes, without the need to copy VM/CT data, and high availability as the storage becomes available remotely.

Choose a name for the cluster that will uniquely identify it among other clusters in your network== Features ==<br clear="both">[[File:Parallels_Cloud_Storage_is_a_software_defined_storage.png|300px|right|link=http://www.youtube. A name may contain the characters acom/watch?v=6oEzW9w-z, A-Z, 0-9, dash (-), and underscore (_). Here we will use 'test_cluster' as 1rg|Virtuozzo Storage is a cluster name.software defined storage]]The main Virtuozzo Storage features are listed below:

===Create metadata server * No special hardware requirements. Commodity hardware (MDSSATA/SAS drives, 1Gbit+ Ethernet)===can be used to create a storage.* Strong consistency semantics. This makes Pstorage suitable for iSCSI, VMs and CTs running on top of it (unlike object storage such as Amazon S3 or Swift).* Usable for Containers or exportable as iSCSI, NFS, S3 object storage* Built-in replication.* Automatic disaster recovery on hard drive or node failures.* High availability. Data remain accessible even in case of hard drive or node failures.* Optional SSD caching. SSD caches boost the overall performance in the cluster on write and read operations.* Data checksumming and scrubbing. Checksumming and scrubbing greatly enhance data reliability.* Grow on demand. More storage nodes can be added to the cluster to increase its disk space. A VM/CT image size is not limited by the size of any of the hard drives.* Scales to Petabytes* More uniform hardware performance and capacity utilization across the nodes, so overutilized nodes benefit from idle ones.* High performance - comparable to SAN.

Log in to the computer you want to configure as See a metadata server as root or as a user with brief [http://www.youtube.com/watch?v=6oEzW9w-1rg video on YouTube].root privileges.<br clear="both">

Download and install the following RPM packages: pstorage-ctl, pstorage-libs-shared and pstorage-metadata-server. The packages are available in the Parallels Cloud Server remote repository (this repository is automatically configured == Pstorage for your system when you install Parallels Cloud Server) and can be installed with this command:OpenVZ limitations ==

<code># yum install pstorage-ctl pstorage-libs-shared pstorage-metadata-server<{{Warning|* Virtuozzo Storage is available as a TECHNOLOGY PREVIEW ONLY for OpenVZ users and can't be licensed for production.* To unlock for running in production, you should upgrade to a full [[Virtuozzo]] product (see below).* Maximum capacity limited for usage in technology preview mode is 100 GB of logical (usable by containers) disk space.* After hitting this limit, writers can get blocked w/code>o errors expecting for a limit to be extended, so please avoid hitting the limit (it's not a bug :) ).}}

<code># pstorage -c test_cluster make-mds -I -a 10[[File:Parallels_Cloud_Storage_components.30.100.101 -r /pstorage/test_cluster-mds -p</code>png|650px|top|Virtuozzo Storage Components]]

This command creates new Parallels Cloud Any Virtuozzo Storage cluster and metadata server and configures the IP address of 10.30.100.101 for communication with this server (replace 10.30.100.101 with IP address of your own MDS server). The command will ask you to enter the password for authentication in your cluster. The password you specify is encrypted and saved into the /etc/pstorage/clusters/pcs1/auth_digest.key file.includes three components:

After you have created the * Metadata server (MDS server). MDSs manage metadata, like file names, start and keep control over how files are split into chunks and where the chunks are stored. They also track versions of chunks and ensure that the cluster has enough replicas. An MDS management service (pstorage-mdsd) and configure it can be run in multiple instances to start automatically when provide high availability. Besides, MDSs keep a global log of important events that happen in the server boots:cluster.

<code># * Chunk server (CS). A CS is a service pstorage-mdsd start</code>responsible for storing real user data chunks and providing access to these data. A Pstorage cluster must have multiple instances of CSs for high availability.

<code># chkconfig pstorage* Clients. Clients access a Virtuozzo Storage cluster by communicating with MDSs and CSs. Virtuozzo Containers and virtual machines can be run natively, i.e. directly from the Virtuozzo Storage cluster. An additional Virtuozzo Storage client -mdsd on</code> can be used to mount Virtuozzo Storage as a conventional file system (though Pstorage is not POSIX-compliant). Besides, Pstorage files can be mounted as a block device using the "ploop" feature and formatted as ext4 file system for other needs.

Every time A recommended cluster setup includes from 3 to 5 MDS instances (allowing you add new server or client to survive the clusterloss of 1 or 2 of MDSs, you need to create the bs.list file in the /etc/pstorage/clusters/Cluster_Name directory (make this directory if it does not existrespectively) on the server you are configuring for the cluster and specify IP addresses and ports of the MDS servers in the clustermultiple CSs providing storage capacity.

<code># echo "10This HOWTO explains how to setup Virtuozzo Storage cluster and run OpenVZ containers stored there.30Please note, that it's just a brief HOWTO for quick and easy evaluation of Virtuozzo Storage (configuring only 1x MDS and CS service) and is not a real manual.100.101We highly recommend to consult [http:2510" >> /etc/pstoragedownload.parallels.com/doc/clusterspcs/test_clusterpdf/bsParallels_Cloud_Storage.pdf Pstorage manual] and man pages (such as pstorage, pstorage-make-cs, pstorage-make-mds etc.) as it contain a lot of important details on types of SSD drives supported, what are the recommended configurations, how to configure big clusters with failure domains and so on.list</code>

===Create chunk server (CS)Installing Virtuozzo Storage software ===

Log In order to install Pstorage RPM packages, log in as root to all the computer you want machines planned to be added to configure as a chunk server as root or as a user with root privilegesthe cluster and perform the following actions.

Download and install the following RPM packages: Set up pstorage-ctl, pstorage-libs-shared and pstorage-chunk-server. The packages are available in the Parallels Cloud Server remote repository (this yum repository is automatically configured for your system when you install Parallels Cloud Server) and can be installed with this command:

cat <code< EOF ># /etc/yum install .repos.d/pstorage.repo [openvz-ctl pstorage-libs-shared ] name=Virtuozzo Storage for OpenVZ baseurl=http://download.openvz.org/pstorage-chunk-server</code>current enabled=1 gpgcheck=0 EOF

Authenticate the server in the clusterInstall needed packages:

yum install pstorage-metadata-server pstorage-chunk-server pstorage-client === Creating a cluster === Every Pstorage cluster has a unique cluster name used for remote service discovery and during authorization.So choose a name for the cluster that will uniquely identify it among other clusters in your network and avoid reusing it on cluster recreate. A name may contain the characters a-z, A-Z, 0-9, dash (-), and underscore (_). Here we will use 'test_cluster' as a cluster name. ==== Create metadata servers (MDS) ==== Log in to the computers you want to configure as a metadata server as root. To create the cluster and the very first MDS type:  pstorage -c test_cluster make-mds -I -a 10.30.100.101 -r /pstorage/test_cluster-mds -p This command creates new Virtuozzo Storage cluster and metadata server and configures the IP address of ''10.30.100.101'' for communication with this server (replace ''10.30.100.101'' with IP address of your own MDS server). MDS will store its data at location specified by '''-r''' option. The command will also ask you to enter the password for authentication in your cluster. After you have created the MDS server, start the MDS management service ('''pstorage-mdsd''') and configure it to start automatically when the server boots:  service pstorage-mdsd start chkconfig pstorage-mdsd on To create a 2nd and subsequent MDS services on other nodes, do the following: 1. Login to the node as root. 2. Setup cluster discovery. Normally, all the Pstorage components should be capable to discover each other on the network using multicast discovery (mDNS). This may not work however in Virtual Machines or if your network doesn't support multicasts. In this case you need to setup an MDS bootstrap list on the nodes manually. To do so create the '''bs.list''' file in the '''/etc/pstorage/clusters/<codecluster_name>''' directory (make this directory if it does not exist) on the server you are configuring for the cluster and specify IP addresses and ports of the MDS servers in the cluster.For example to create a bootstrap list for above cluster created type: echo "10.30.100.101:2510" >># /etc/pstorage/clusters/test_cluster/bs.listNow future Pstorage services started on this machine will be able to discover other parties. 3. Authenticate the server in the cluster and add a new MDS to the cluster using similar to the above make-mds command w/o -I and -p options: pstorage -c test_cluster auth-node< pstorage -c test_cluster make-mds -a 10.30.100.102 -r /pstorage/code>test_cluster-mds ==== Create a chunk server (CS) ==== Log in to the computer you want to configure as a chunk server as root.Note, you may need to setup a bootstrap list as described above in case cluster auto-discovery doesn't work. Authenticate the server in the cluster (skip this step if configured MDS or CS already on that server): pstorage -c test_cluster auth-node

Create a CS:

<code># pstorage -c test_cluster make-cs -r /pstorage/test_cluster-cs -t 1</code>

This command will create a CS service and use the directory specified after '''-r''' option for CS data store.After you have created the chunk server, start the chunk management is as a service ('''pstorage-csd''') and configure it to start automatically when the chunk server machine boots:

<code># service pstorage-csd start</code> chkconfig pstorage-csd on ==== Setting up a client ==== Log in to the computer you want to act as a client as root.Note, you may need to setup a bootstrap list as described above in case cluster auto-discovery doesn't work. Authenticate the server in the cluster (skip this step if configured MDS or CS already on that server):  pstorage -c test_cluster auth-node The command will ask you the password that you specified when setting up the first MDS server.

Log in You may want to the computer you want add this mount to /etc/fstab to act as a client as root or as a user with root privilegesmake it happen automatically on node reboot. Consult ''man pstorage-mount'' for more details.

Download and install Now you can access your data from all the following RPM packages: pstorage-libs-shared and pstorage-client. The packages are available in the Parallels Cloud Server remote repository (this repository is automatically configured for your system when you install Parallels Cloud Server) machines and can be installed with this command:ready to run containers!

Create Running a container over Pstrage is no different from any other local file system, so below example is just for the directory reference.Log in to mount the Parallels Cloud computer running OpenVZ and that you have configured to act as a client for the Virtuozzo Storage cluster to:.

<code># pstorageMount Pstorage cluster at '''/pcs''' as described above if not done yet. Create a folder on Pstorage for the containers: mkdir -mount -c test_cluster /mntp /pcs/</code>containers

For more information on setting up pstorage cluster please refer to the Parallels Cloud Storage documentation [httpCreate a ploop-based container with CTID=101 (put your own template name below)://download.parallels.com/doc/pcs/pdf/Parallels_Cloud_Storage.pdf http://download.parallels.com/doc vzctl create 101 --layout ploop --ostemplate centos-6-x86_64 --private /pcs/pdfcontainers/Parallels_Cloud_Storage.pdf].101

Now container with CTID==Create ploop-based 101 is ready for use and can be started on '''any''' Pstorage client node (note, however, that you need to register container inside cluster==first if want to run on node different from creator one):

Create folder for '''[http://www.odin.com/products/virtuozzo/ Virtuozzo]''' is a unique virtualization server platform combining both hypervisor and container data:-based virtualization together with innovative storage virtualization.

<code># mkdir -p Please request more information on upgrading to Virtuozzo at the [http:/mnt/pcswww.odin.com/container<products/code>virtuozzo/ product page] (look for '''Request Information''' button).

Create ploop-based container with CTID=101 (replace template name with your own template):= External links ==

<code>vzctl create 101 --layout ploop --ostemplate centos-6-x86_64 --private * [http://www.odin.com/fileadmin/media/hcap/pcs/documents/ParCloudServer6_DataSheet_EN_Ltr_111312.pdf Virtuozzo product datasheet]* [http://www.odin.com/fileadmin/media/hcap/pcs/documents/ParCloudStorage_DataSheet_EN_Ltr_02262013.pdf Parallels Cloud Storage product datasheet]* [http://download.parallels.com/doc/pcs/pdf/Parallels_Cloud_Storage_Administrators_Guide.pdf Parallels Cloud Storage Administrator's Guide]* [http://www.odin.com/fileadmin/media/mnthcap/pcs/containerdocuments/<PCloudStorage_Performance_Results_WP_EN_Ltr_02192013_web.pdf Pstorage performance whitepaper]* [http:/code>/www.youtube.com/watch?v=6oEzW9w-1rg Pstorage introduction video]