During my first two months as a Systems Engineer for PernixData I have seen a lot of similar question from customers and during POC engagements. All good and valid questions. I felt like it would be a good thing to share it with everybody out there who are looking into PernixData FVP.
Top 20 FAQ on PernixData FVP:
Q1: What is PernixData FVP?
A: PernixData FVP is a kernel module installed inside the ESXi hypervisor that uses local flash as a transparent cache to accelerate virtual machines storage performance.
Q2: What storage protocols does PernixData FVP support?
A: PernixData FVP supports block storage. FC, FCoE and iSCSI
Q3: What about NFS support?
A: Currently there is no support for NFS as the backend storage.
Q4: What version of VMware is supported with PernixData FVP?
A: As of writing PernixData FVP supports vSphere 5.0 and 5.1.
Q5: What about support for vSphere 5.5 and the new Web Client?
A: vSphere 5.5 and full web client support is coming soon. It is currently in beta. You can request access to the beta here: http://beta.pernixdata.com
Q6: What kind of Flash devices do you support?
A: We support every flash device that is on the VMware’s HCL list. This could be PCIe or SSD drives.
Q7: So PernixData FVP is a caching solution. Is it only Read cache it supports?
A: PernixData FVP supports Write Through (Read) and Write Back (Read & Write) caching.
Q8: Write Back caching, how do you make sure I don’t lose data in case of host or SSD failure?
A: PernixData gives you the option to choose 1 or 2 replicas partners. If you choose two your write data will be acknowledged from three SSD in three different hosts.
Q9: What network do you use for replication traffic. Can I select another one?
A: PernixData by default selects your vMotion vmkernel adapter. You can choose another one and put it on a dedicated vSS/vDS with dedicated physical nics.
Q10: Does PernixData FVP work with DRS, HA, vMotion etc.?
A: PernixData has full support for all VMware clustering features. The administrator will still be able to vMotion, use HA in case of a host failure and DRS can distribute the virtual machines.
Q11: Wow! Impressive, there must be some VMware features you do not support?
A: PernixData does not accelerate Raw Device Mapped disks (RDM) and PernixData does not support VMware fault tolerant protected virtual machines.
Q12: What VMware licenses do I need to get started with PernixData FVP?
A: PernixData supports any VMware vSphere license. It does not matter if it is Essentials, Standard, Enterprise or Enterprise plus.
Q13: Is it complicated to install?
A: PernixData FVP is a very simple install. It consists of a management server running on windows, the FVP host extension installed inside the VMkernel and a plugin for the vSphere Client.
Q14: So I have bought two SSD’s for my hosts in my cluster. How should I configure my RAID controller? Is RAID0 good for performance and RAID1 good for security?
A: You should not configure RAID0 or RAID1. Keep it simple and direct attach the disks as JBOD. If JBOD is not possible then configure a RAID0. For best performance we prefer not to use the RAID controller at all.
Q15: How much flash cache do I need in each ESXi host?
A: This is not a simple question to answer. It depends on the working set of the virtual machines. As of writing we see most customers going with 200/400GB flash pr. host.
Q16: So I have been running PernixData for some time now, how do I know if I need more flash?
A: Inside the PernixData tab in vCenter we show you the eviction rate. If you see evicted data it means you can benefit from more flash.
Q17: Do I need the same flash type and size in every ESXi host?
A: PernixData is very flexible. It is a good design to use similar flash type and size to get predictable performance. But if you want to add 1TB Enterprise flash in one server and 200GB consumer flash in another we won’t stop you.
Q18: What kind of workloads can I accelerate with PernixData FVP?
A: Because PernixData is a clustered solution with WT and WB cache you can protect any workload. It does not matter if it is VDI or normal servers.
Q19: What kind of latency can expect for my virtual machines with PernixData?
A: It depends on the flash device and the workload. But microseconds and very low milliseconds range.
Q20: How do I get started with your software if I want to try it?
A: You can request a free trial on www.pernixdata.com and try it out for 60 days. During the trial you have access to a Systems Engineer from PernixData who will help you out with any questions you might have.