There’s no doubting HDS‘ Universal Volume Manager (UVM), aka external storage virtualisation is a cool product. I’ve used it many times – it does the job. However, the main drawback to using the product for me was always cost (I mentioned this only a few weeks ago on this post). Well, now that’s changed; until the end of this year, HDS are offering UVM for free. See the announcement here. HDS are calling it their “Switch It On” campaign.
OK, free isn’t quite free – there are a few caveats. Customers have to pay for maintenance, but other than that, there’s no charge for using UVM on current USP-V deployments. In addition, customers can “super-size” the offer and also get Hitachi Tiered Storage Manager (HTSM), Hitachi In-System Replication and limited access to Hitachi Dynamic Provisioning (HDP) all for free.
It is unlikely HDS are doing this out of some altruistic concern for their customers. Clearly they see benefits in driving more business by offering these licences at no cost. So how can customers benefit?
Traditionally, UVM is seen as a tool to manage the migration process or get data into a USP and there’s no question that UVM can be used for these purposes. Typically, here are some of the costs associated with migration:
- Staff Resource Costs – migrations take time and effort to plan. The longer they take, the more cost is incurred with change control, planning, co-ordination with other teams and on actually performing the migration, which is typically performed out of hours.
- Software Costs – migrations may require specific software products or tools (e.g UVM or TDMF).
Here are some of the constraints on migration work:
- Limited downtime on servers.
- Data to be migrated out of hours or within certain time frames.
- No host tools (like volume managers) to perform migrations.
- Data migrations are required to disparate locations.
- Data integrity and synchronicity must be maintained (e.g. replicated data must be consistent if an outage occurred during the migration process.
The tradeoff with UVM has always been the cost of the UVM licence compared to the savings which could be made on the above issues by using the product. For example, UVM could be used to virtualise an entire array (or arrays) behind a USP-V in a single weekend. Consecutive weekends can then be used to migrate into the USP. This controlled approach (a) enables the storage managers to perform the migration, freeing up the host teams (b) allows the storage managers to load balance migrations into the USP-V (c) monitor performance as migrations occur (d) enable target servers to be immediately upgraded to new code/driver levels which may not have been supported previously on the older arrays.
Getting UVM for free enables some more lateral thinking:
- Example 1: Migrate out of the USP. There are lots of examples of moving data into a USP, but what about moving it out? If you’ve purchased a USP and it’s fully populated with disk and full, how do you save money? Well, one option is to get a UVM licence and migrate non-critical (and perhaps non-production) data to an externalised array at a lower cost. Previously this could only be commercially viable if the reduced cost of the external array covered the cost of the UVM licence. Now there’s no need to worry.
- Example 2: Migrate in and De-Dupe. With UVM and HDP, external storage arrays can be migrated into the USP and placed on thin provisioned volumes. HDP Zero Page Reclaim removes the “empty” blocks of data during this process. For certain data profiles, this could provide signficant savings.
- Example 3: A Free Datacentre Migration Tool. Imagine you’ve got to move data on arrays not currently replicated – but that data needs to reside in another location. If a pair of USPs are available, why not virtualise the source and target arrays and use the USP to move the data between the two sites? This could save purchasing replication licences for an array or resolve a problem where replication isn’t possible from certain hardware.
- Example 4: Implement a 3DC Solution. How about using the USP-V as a three datacentre solution? Here’s how it works; two USP-Vs are used to replicate data synchronously between two local sites. The target devices are actually virtualised across a fabric to a third site using UVM. In this way, data can be moved to a third site without requiring a third copy of data.
With free software, the options are only limited by imagination. If HDS are prepared to offer software for free then there’s no excuse not to use it.