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Grocery retailer Coop Denmark has deployed VMware’s Virtual SAN (VSAN) software-defined storage with all-flash storage to support 1,200 virtual machines (VMs). The move brought decreased costs and simpler management and has seen the company phase out its use of NetApp filers.
The Coop has 1,200 stores in Denmark as well as in Greenland and the Faroe Islands, with 40,000 employees and 100,000 products on its shelves.
Core business processes are in the main supported by VMware-based virtualisation, with 1,200 virtual machines. A small portion of processes run on IBM mainframe and Unix servers.
The organisation’s existing storage was provided by NetApp filers, but the Coop was keen to simplify IT operations and cut costs, said IT enterprise architect, Soren Vendler.
“We’re always looking for ways to cut costs and make our landscape simpler. The less specialised functions we need to maintain the lower the cost and VSAN is a way to eliminate an entire discipline,” he said.
The organisation had run into performance bottlenecks with its existing NetApp storage with Metro Clustering deployed.
“We have a policy of mirroring all data between sites. NetApp prefers Metro Clustering for that. It splits the storage system so everything is mirrored without the need for replication policies on individual volumes,” said Vendler.
“However, Metro Clustering is vulnerable to inconsistencies between the two halves of the ‘brain’ when bandwidth is short. We could have put more NetApp instances in but that would have meant more cost.”
In a technology refresh, Coop Denmark deployed four groups of eight HP DL380 servers with all-flash storage at separate sites on its Copenhagen campus to run the vSphere hypervisor environment plus VSAN storage.
VMware VSAN aggregates server-attached disk (DAS) into a single pool of storage that can comprise spinning disk HDDs with flash disk for high-speed metadata. Using software acquired from Virsto in 2013, it is able to provide speedier write access to virtual machine storage by logging write requests and making them sequential rather than random.
Read more about VMware Virtual SAN
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VSAN provides a single storage namespace, with all VMs and their data replicated to another set of hardware on the Copenhagen campus.
Vendler said deployment of new VM storage is easier than previously but that getting the configuration right on VSAN is critical.
“Provisioning is a very simple process compared with what we are used to, but don’t underestimate the delicacy of design. VMware specified the design of the product right down to the tiniest configuration values in a detailed blueprint and this is the only way to ensure performance and stability.” he said.
“This is critical to maximise the possibility of success and now we have the templtes to allow us to scale out. But, you can find customers that have been less careful and run into problems.”
Could VMware improve VSAN? Yes, said Vendler; by providing software-defined storage with Fibre Channel SAN connectivity and simple file shares.
“VMware is already beginning to do it; I wish for VSAN to be able to provide Fibre Channel LUNs for physical servers. We have 50 Unix servers that need LUNs and we’re still using NetApp for those. Also, to be able to do simple file shares would be good.”