With the announcement of vSphere 5.0 VMware also announced the first edition of the vSphere Storage Appliance (VSA). This new product is targeted toward SMBs who may not have the budget or want to deal with the complexity of building a storage infrastructure, but who would like to leverage more advanced features of ESXi/vCS like DRS and HA.
Since its announcement, I have been asked several times if/when this product should be implemented. While there are some very good use-cases for this product, it is important to understand the current target audience and the limitations of this release. Below are the details one should keep in mind.
Configurations
- 2-member cluster + vCS service
- 3-member cluster
ESXi 5.0
- CPU: 2GHz or greater.
- Memory: 6GB minimumn, 24GB recommended, 72GB maximum supported.
- Network
- Four gigabit ethernet NICs minimum. 10G NICs are not supported.
- Each ESXi host must be assigned a unique static IP address that is in the same subnet as the vCenter Server IP address.
- Back-end cluster/mirroring/iSCSI network IP must be in 192.168.x.x.
- All networking is configured via traditional vSwitches. vNetwork Distributed Switches are not supported with VSA.
- Resources
- ESXi hosts must have no deployed virtual machines before creating the cluster.
- Consider the vSphere HA admission control reservations when determining the number of virtual machines and the amount of resources that your cluster supports. vSphere HA admission control reserves 33% of all CPU and memory resources in a 3-member VSA cluster and 50% of all CPU and memory resources in a 2-member cluster. vSphere HA admission control makes the reservations to ensure that resources are available when virtual machines need to be restarted from a failed ESXi host onto a running ESXi host.
- VSA datastores do not support VMX (guest VM) swapping due to performance reasons. The documentations states that because of this, you should reserve the configured memory of all non-VSA virtual machines that use VSA datastores so that you do not overcommit memory.
- Storage
- A combination of SATA and SAS disks is not supported; JBOD is not supported.
- 4, 6, or 8 disk spindles only.
- 2TB maximum capacity per hard disk, 180GB minimum total hard disk space per ESXi host.
- The VSA cluster requires RAID volumes created from the physical disks. The vSphere Storage Appliance uses RAID1 to maintain the VSA datastores replicas.
vCenter Server 5.0
- vCenter Server must be installed and running before you create the VSA cluster
- Do not change the default vCenter Server ports, as it might lead to VSA upgrade failures
- In a 2-member VSA cluster, install vCenter Server on a physical host or as a virtual machine on an ESXi host that does not participate in a VSA cluster. If you run vCenter Server on a VSA datastore and the datastore goes offline, you might not be able to manage the VSA cluster due to the loss of access to vCenter Server and VSA Manager.
- In order for DRS to function fully with Fault Tolerant VMs, EVC must be enabled. If EVC is not enabled then if DRS is enabled DRS is only used to fully automate the initial placement of the secondary VM.
vSphere Storage Appliance 1.0
- At least two of the three VSA services must remain online for the storage to remain online
- You cannot add another VSA cluster member to a running VSA cluster. For example, you cannot extend a 2-member VSA cluster with another member.
References
- http://pubs.vmware.com/vsphere-50/topic/com.vmware.ICbase/PDF/vsphere-storage-appliance-10-install-config.pdf
- http://communities.vmware.com/servlet/JiveServlet/previewBody/17932-102-1-23101/VM-vSphere-Storage-Appliance-Deep-Dive-WP.pdf
© 2012, Steve Flanders. All rights reserved.
