RealStor 2.0 Provisioning and Mapping Volumes What you ll learn: Learn about new concepts and terms for provisioning storage pools from disks and creating volumes with RealStor Use the new Storage Management Console to define Disk Groups for new Virtualized Pool as well as traditional Linear Pools. Learn how to create volumes and efficiently map them to hosts. Introduction RealStor 2.0, will give users access to several new key features including automated-tiering, thin provisioning, SSD read cache, storage pooling, and several other important features. The new features will be accessed via the Storage Management Console, referred to as V3. Refer to Figure 1 for an example of the V3 interface. Figure 1 V3 Home Screen In addition, the firmware will also incorporate the existing RAIDar 2.0, referred to as V2, to allow existing AssuredSAN 4004 customers to maintain their current configurations and management interface. This
document assumes the user is familiar with the current management system and will highlight differences in the V3 SMU. This specific brief will focus on Provisioning and Mapping with the new interface. Provisioning with V3 Interface Unlike prior AssuredSAN arrays which use VDisks, with the RealStor 2.0 firmware users will create storage pools by creating and adding Disk Groups. Disk Groups are similar to VDisks but can have different types Virtual, Read Cache and Linear. Virtual a new methodology where volumes are managed in discrete 4MB entities (called pages ) which enable several key new features (see Volumes section below for more information) Read Cache allows the customer to increase the effective controller cache size by adding SSDs as a read-cache Disk Group Linear allows users to create VDisks similar as they do in the GL105 code by selecting disk drives, RAID level, chunks size, etc. Linear refers to the current methodology of the GL105 code and how it manages Volumes on VDisks. This brief will focus on the Virtual Disk Groups and the new features and benefits that this enables. (Linear Disk Groups will behave the same way that VDisks do in the GL105 and previous releases and will not be addressed here. Read Cache will be addressed in an accompanying technical feature brief available online.) Virtual Disk Groups When creating a Virtual Disk Group, the user can specify the RAID level (RAID 1, 5, 6, 10) and which Pool the Disk Group belongs to. Disk Groups must contain like disk types: SSD, Enterprise SAS, MDL SAS. The user must select a valid group of available HDDs or SSDs for the chosen RAID type. These configuration rules are the same as creating a VDisk with the prior V2 interface. Unlike creating VDisks in the V2 SMU, the chunk size is automatically set to 512KB and does not need to be modified by the user. An example of the V3 Add Disk Group Screen is shown below in Figure 2.
Figure 2- Add Disk Group Screen Once the virtual Disk Groups are created, the RealStor 2.0 will create pools comprised of the individually created Disk Groups. Similar to GL105, the array utilizes an active-active controller configuration, and will create a Pool A and Pool B each with the primary owner of Controller A and Controller B respectively. Best practices would leverage both controllers and balance the workload across the two pools.
Figure 3 is an example of the V3 Home screen with two pools comprised of Enterprise SAS (color coded light green) and MDL SAS (color coded light blue) disk components. Figure 3- Home screen with Pools Provisioned Volumes in Virtual Disk Pools: To further explain the virtual disk pool concept, we will first look at how volumes are treated in the virtual disk pool. One of the key concepts of the RealStor 2.0 firmware is the addition of a virtualization layer which allows a volume s data to be segmented into discrete 4MB entities called pages. These 4MB pages are managed individually, and can allow a volume s data to be spread over potentially multiple underlying storage pool Virtual Disk Groups and potentially multiple tiers (SSD, Enterprise SAS, MDL SAS) of disks. See figure 3. Copy Services Virtualized Volume 4MB virtualized pool Virtual Disk Group Figure 4- Virtual Volume disks disks disks SSD SAS MDL
Mapping in the V3 Interface: Once the users have added their Disk Groups to create the Pools, they may now create and map volumes. This is very similar to how the customers currently create volumes in GL105 firmware, however volumes are now assigned to a pool instead of a VDisk. RealStor 2.0 includes the ability to assign volumes to groups. This grouping capability enables large numbers of initiators to be mapped to LUNs in a single operation improving the efficiency and organization of host configuration. In addition, the V3 SMU incorporates search filters that greatly simplify the task of managing large numbers of volumes and reduce management time. To map a volume, the user may select the Mapping topic, or click on the volume and select Mapping under the action tab. The Mapping screen in the V3 interface is different than the V2 version and contains several enhancements. Users may now create initiator names, assign to Hosts, and then assign Host to Host Groups. This greatly simplifies the tasks of managing and mapping large numbers of Hosts that may have the same mapping requirements. Filter capabilities also exist for the Host and Host group tables. RealStor 2.0 allows for users to do default mapping by selecting All other initiators. Selecting this will make the volume available to all host ports. The user may also do explicit mapping - mapping to individual initiators, hosts, or host groups. The Storage Management Console will map to both the A and B controller by default for each port. Figure 5 is an example of the Mapping Screen. Figure 5- Mapping Screen in RealStor s Management Console
Provisioning and Mapping with the CLI Interface: RealStor 2.0 will support a robust CLI interface. RealStor 2.0 maintains a set of commands for the Linear (V2) interface, and a separate set of commands specific to the new paged (V3) interface. While much of the command-set is shared between the two, there are some significant differences which are required to maintain backwards compatibility while allowing users to manage both versions in the same CLI. While this document is not intended to highlight all the differences, some of the commands specific to provisioning and mapping that customers will want to review are highlighted here. For detailed description of all the changes, CLI Reference guide will be available. First, specific to setting a management interface, Set protocols and set cli-parameters will include support for setting the management-mode interface to v2 or v3 at both a global (set protocols) or session level (set cli-parameters). This setting will dictate which CLI commands are used. With the introduction of the term disk group, RealStor 2.0 will provide a new set of CLI commands to configure disk groups: add disk-group, remove disk-groups, show disk-groups, etc. Disk groups are a group of disks that together form a RAID set. In a V2 (RAIDar 2.0) environment, disk groups are exactly the same as vdisks. Commands used to manage vdisks in GL105 code will be the same as in the V2 interface. With volumes now residing in pools, a new set of CLI commands is available to manage them; show pool, remove pool, etc. As highlighted above, the CLI will allow supporting for host groups in both the V2 and V3 interface modes. However, the term host can have a different meaning depending on whether you are grouping, or using the legacy context of the command. RealStor 2.0 will also introduce volume groups for virtual volumes. For additional information regarding CLI command changes, please refer to the CLI Reference Guide for a more detailed description. Summary: New or current AssuredSAN 4004 model users, who are looking to maximize the abilities of their storage, can upgrade to RealStor 2.0 and begin taking advantage of the many new features that are available (some licensing may be required). In addition to the new mapping and provisioning capabilities, the new firmware enables several other key features including automated-tiering and read cache, thin provision, and new copy services features. Whether its leveraging a small set of SSDs for tiering or read cache, to simplified management of large numbers of hosts the RealStor 2.0 will provide users powerful new capabilities while still maintaining backwards compatibility with current configurations. 2014 Copyright Dot Hill Systems Corporation. All rights reserved. Dot Hill Systems Corp., Dot Hill, the Dot Hill logo, and RealStor are trademarks or registered trademarks of Dot Hill Systems. All other trademarks are the property of their respective companies in the United States and/or other countries. 8.4.14