vsphere Storage Appliance TECHNICAL WHITE PAPER

Transcription

1 vsphere Storage ppliance TECHNICL WHITE ER v 1.0/Updated June 2011

2 Table of Contents Introduction rchitectural Overview... 3 Managing and Monitoring Conclusion... 9 TECHNICL WHITE ER / 2

3 Introduction In VMware vsphere 5.0 ( vsphere ), VMware is releasing a new software storage appliance to the market called the vsphere Storage ppliance (). This appliance provides an alternative shared storage solution for small-to-medium business (SMB) customers who might not be in a position to purchase a SN or NS array for their virtual infrastructure. Without shared storage configured in a vsphere environment, customers have not been able to exploit the unique features available in vsphere 5.0, such as vsphere High vailability (vsphere H), vsphere vmotion (vmotion), and vsphere Distributed Resource Scheduler (vsphere DRS). The is designed to provide shared storage for everyone. This paper presents an overview of the architecture, deployment of a storage cluster, and basic monitoring and managing. rchitectural Overview can be deployed in a two-node or three-node configuration. Collectively, the two or three nodes in the implementation are known as a storage cluster. Each VMware server has a instance deployed to it as a virtual machine. The instance will then use the available space on the local disk(s) of the VMware servers to present one mirrored NFS volume per VMware. The NFS volume is presented to all VMware servers in the datacenter. Each NFS datastore is a mirror, the source residing on one (and thus, one VMware ), and the target residing on a different (and thus, a different VMware ). Therefore, should one (or one VMware ) suffer a failure, the NFS datastore can still be presented, albeit from its mirror copy. This means that a failure in the cluster is transparent to any virtual machines running on that datastore. vsphere vsphere vsphere Manager vsphere Client NFS NFS NFS Figure 1. Three-Member Cluster The can be deployed in two configurations: 3 x VMware 5.0 server configuration 2 x VMware 5.0 server configuration The two different configurations are identical in the way in which they present storage. The only difference is in the way that they handle storage cluster membership. The following section covers the details of a threenode and two-node storage cluster. TECHNICL WHITE ER / 3

4 vsphere Storage ppliance Three-Node Configuration In the three-node standard configuration, each node runs an instance of. Each node presents a file system via NFS that is mirrored to one other file system on another. To prevent any sort of split-brain scenario, the three-node configuration requires at least two nodes to be running in order to maintain a majority of nodes. vcenter Server Manager Manage Datastore 1 Datastore 2 Datastore 3 Volume 3 Volume 1 Volume 1 Volume 2-1 Volume 2 Volume Cluster with 3 members Figure 2. Three-Member Cluster In Figure 2, the three NFS datastores in the oval are NFS file systems. These file systems are presented as NFS datastores to the VMware servers in the cluster. TECH N I C L WH ITE E R / 4

5 vsphere Storage ppliance Two-Node Configuration The two-node configuration uses a special cluster service, which runs on the VMware vcenter Server. This behaves as a cluster member and is used to make sure that there is still a majority of members in the cluster, should one VMware server member fail. There is no storage associated with the cluster service. vcenter Server Manager Cluster Service Manage Volume 2 Volume 1 Datastore 1 Datastore 2-1 Volume 1 Volume 2 Cluster with 2 members -3 Figure 3. Two-Member Cluster In Figure 3, the datastores in the oval are NFS file systems presented as shared storage to the VMware servers in the datacenter. Installation installation is started by installing the manager software on an existing VMware vcenter Server. NOTE: In this release of, an instance of VMware vcenter Server 5.0 can only manage a single storage cluster. Once completed, a vsphere client is opened and pointed to the VMware vcenter Server, and the manager plug-in is enabled. This creates a manager tab in the vsphere client. The manager tab then navigates the customer through the remaining installation steps. During the installation, a datacenter must be selected, after which a list of VMware servers in that datacenter is presented. The installer will check the compatibility of each of these hosts to make sure they are suitable for deployment. Out of the compatible hosts, a maximum of three hosts can be selected to participate in the storage cluster. If the hosts are unsuitable for any reason (for example, if hardware is not supported, or networking is not configured), the installer will report it and will not enable the user to select that particular host. The installation process scans all of the local storage attached to the VMware host, and then makes plans to use space not currently in use by the VMware boot image for data storage. The user is warned in several places that any existing data will be overwritten. Once this is complete, the storage is configured as a datastore and exported to other members in the storage cluster. TECH N I C L WH ITE E R / 5

6 During the installation, the installer does some additional housekeeping to enable the user to take maximum advantage of the shared storage now available. First, the installer configures a vmotion network between the nodes in the storage cluster. This enables the user to initiate the vmotion process on any virtual machines configured to run on the hosts that make up the storage cluster. The installer also automatically builds a vsphere H cluster covering the VMware hosts in the storage cluster. This protects any virtual machines running in these hosts. For environments with additional hosts in the vsphere datacenter beyond the storage cluster, the user can manually extend the vmotion network configuration and vsphere H cluster configuration to encompass these hosts. Managing and Monitoring The manager UI enables administrators to view the status of all instances and datastores in the storage cluster. The interface is integrated into VMware vcenter, giving it a familiar look and feel, and helps an administrator to deploy, manage, and monitor instances and the storage cluster. First, we can look at the monitoring capabilities. t deployment time, each will host a primary datastore and a replica. Figure 4 presents a view of the members, shown by clicking on the ppliances button in the center-left position of the window. In this example, it is a three-member configuration. By default, the members are labeled -0, -1, and -2. The Hosted Datastores and Hosted Replicas columns show that each member continues to host a primary datastore and a replica. The user can also see which VMware server is hosting the via the Host column. Finally, we can see that all the members are Online via the Status column. By selecting a member, additional properties are displayed in the lower half of the screen, including frontend/management Network and the Back-End Network/features details. Figure 4. Manager s View TECHNICL WHITE ER / 6

7 Datastores view and a Maps view are also available to assist administrators with monitoring the cluster. The supports the concept of the maintenance mode, both for the individual instances and for the storage cluster as a whole. Maintenance mode enables administrators to take individual members or the whole storage cluster offline in a controlled and structured manner. To put the whole cluster into maintenance mode, select the Enter Maintenance Mode link in the Cluster roperties highlighted in Figure 5. Figure 5. Manager Cluster Maintenance Mode NFS exports from the members become inaccessible when the whole cluster is put into maintenance mode. The cluster is still up, but the NFS services and datastores are taken offline. n individual member can also be placed into maintenance mode by selecting a member from the ppliances view, and then clicking the Enter Maintenance Mode link. This is not the same as the VMware maintenance mode or the vsphere DRS maintenance mode. Rather, it is a maintenance mode specific to cluster members. These actions will shut down the member. If the whole cluster is already in maintenance mode, no further action is necessary. The best practice for using the maintenance mode is to first put the whole cluster into maintenance mode, and then to place individual members into maintenance mode. TECHNICL WHITE ER / 7

8 When a member is placed into maintenance mode, the following states will show up in the Manager > s view: Figure 6. Manager Maintenance Mode Status In Figure 6, member -0 has been placed into maintenance mode. -0 was hosting the primary datastore Ds-1 and the replica for Ds-0. However, since we placed this member into maintenance mode, another member had to take over the export of the primary NFS datastore. In this case, it is Ds-2, as shown in the Exported Datastores column. TECHNICL WHITE ER / 8

9 Conclusion enables users to get the full range of vsphere features, including vsphere H, vmotion, and vsphere DRS, without having to purchase a physical storage array to provide shared storage, making a very cost-effective solution. is very easy to deploy. Many of the configuration tasks, such as network setup and vsphere H deployment, are done by the installer. The benefit here is that this product can be deployed by customers who might not be well versed in vsphere. It gives them a good first-time user experience. is very resilient. If a VMware server that is hosting one of the s goes down, or one member suffers an outage, with the redundancy built into the, the NFS share presented from that will be automatically and seamlessly failed over to another in the cluster. bout the author: Cormac Hogan is a Senior Technical Marketing Manager responsible for storage in the Infrastructure roduct Marketing group at VMware. His focus is on core vsphere storage and virtual storage in general, including and other storage technologies. He was one of the first VMware employees at the EME headquarters in Cork, Ireland, in pril He spent two years as the Technical Support Escalation Engineer for Storage before moving into a Support Readiness Training role, where he developed training materials and delivered training to technical support and VMware support partners. VMware, Inc Hillview venue alo lto C US Tel Fax Copyright 2011 VMware, Inc. ll rights reserved. This product is protected by U.S. and international copyright and intellectual property laws. VMware products are covered by one or more patents listed at VMware is a registered trademark or trademark of VMware, Inc. in the United States and/or other jurisdictions. ll other marks and names mentioned herein may be trademarks of their respective companies. Item No: VMW-W-vSHR-STOR--USLET-101