Is there any popular software that allows me to share PCI Express solid-state drive cards?
Most of the major PCIe vendors provide a software offering to share their cards. Most of the software will create a private network between servers and then allow a server without a PCIe SSD card to connect to a server with one installed. The implementations of this sharing tend to vary from vendor to vendor, but there are generally three types.
The first method places PCIe SSD cards in one server or dedicated appliance and shares the SSD capacity with other servers through a private network connection utilizing iSCSI or some other storage protocol. A server with the PCIe SSD in this case essentially becomes a storage system. This method is ideal for situations where you need the very low latency of a local SSD on a particular server, but also want to share the SSD resource to allow other servers that are less sensitive to latency to leverage the SSD.
The second method is where each, or at least multiple, servers have PCIe SSD cards installed on them and are clustered together creating a common PCIe SSD pool. This is similar to how a traditional scale-out storage system is designed. While this method incurs the latency overhead of a network, storage performance will still be very impressive. This solution also has the advantage of being totally shared, which means clustered systems like VMware or Oracle work well in these configurations.
The third method is a synchronous mirror between two servers. Again, there is some latency produced from the network, but it is minimal since the connection is point to point. These mirrors will often integrate with products like VMware Fault Tolerance to automate failover of virtual machines and applications. Some can also leverage InfiniBand to minimize the latency caused by the network.
The larger question is if you really need a shared SSD resource, should you consider PCIe-based SSD? All the PCIe SSD offerings re-introduce latency at some level, and very few of them reduce costs. If a shared SSD resource is required, you might want to consider a shared storage system that is either all-flash or hybrid SSD.
About the expert: George Crump is a longtime contributor to TechTarget, as well as president and founder of Storage Switzerland LLC, an IT analyst firm focused on the storage and virtualization segments.
This was first published in May 2013