Inspired by the offer of Sanbolic to give away not for resale (evalution) licenses of Melio FS to infrastructure architects I decided to have a first look at the product. In this posting I will focus on the Quality of Service feature of Melio FS.
Melio FS is a 64-bit symmetrical cluster file system that provides multiple servers with simultaneous read/write access to data stored on the same partition or Logical Unit Number (LUN) on SAN storage.
Melio FS is much more advanced than Microsoft Clustered Shared Volumes (CSV) which is available since Hyper-V R2 was released. Differences between CSV and Melio FS are described in this blogposting of Sanbolic.
The shortcomings of Microsoft CSV are described in this blogposting on my website.
This video called ‘Microsoft Hyper-V R2 demo using Sanbolic’s Melio FS and LaScala Volume Manager’ gives a good overview of Melio FS
I will publish more info on my blogsite about the features of Melio FS in the near future. One of the features offered by Melio FS and not by CSV is Storage Quality of Service. Another important difference is that CSV can only be used for storing Hyper-V Virtual Hard Disk (VHD) files. Microsoft does not support storage of other files types on CSV enabled volumes and you will have to confirm this when CSV is enabled.
Melio FS on the other hand is a true 100% multi node clustered file system. Any type of file stored on a Melio FS formated volume can be accessed by any node in a cluster.
Storage Quality of Service in vSphere and Hyper-V
Performance problems on virtualized infrastructures are often related to storage. In most cases enough CPU and internal memory resources are available. But having several virtual machines running on the same LUN can cause bottlenecks. Before the release of VMware vSphere 4.1 storage issues could only be solved by spreading VM with high I/O demand over several LUN’s. Since vSphere 4.1 VMware offers a feature called Storage I/O Control (SIOC). This feature, available exclusively in the Enterprise Plus Edition, can best be described as Quality of Service for disk i/o. When disk latency reaches a certain threshold SIOC kicks in and will give certain VM’s more disk io bandwidth than other VM’s. Priority can be controlled using shares. More on SIOC can be read here.
Melio FS QoS has the same feature. It allows a user to assign a specific amount of the total throughput available in a storage controller to one or more processes running on a machine and/or one or more VHDs.
Priorities are managed by a point system starting with the lowest priority (1) and ending with the highest priority (1000).
Here is a scheme of the processes points:
A – 10 points
B – 10 points
[Default] – 5 points
C – 1 point
D – 1 point
Based on the above described point scheme, with Process A and Process C running at the same time, IO bandwidth will be redistributed between them as follows: Process A will have 9/10 (90%) of the bandwidth reserved, while Process C will have only 1/10 (10%) of the bandwidth.
The image below shows how Quality of Service can be configured in the user interface of Melio FS. Either a process can be assigned points (or shares) or a file. When Hyper-V is used, storage bandwidth can be controlled on a per virtual machines base by assigning VHD file more or less points.
Microsoft does not offer a feature for Quality of Service on storage. If an organization has performance issues related to storage, the usage of Melio FS filesystem can be a good solution.
Melio FS comes in 4 different product suites: Melio Virtualization, Melio VDI, Melio Enterprise and Melio Cloud. Depending on the needs one of the four suites can be selected. This document gives an advice on which product suites best.
The Suggested Retail Price of the suites are as follows:
Melio Virtualization – $249
Melio VDI – $4995 plus annual support
Melio Enterprise – $5995 plus annual support
Melio Cloud – $7995 plus annual support
Melio is licensed per server. With one license of Melio Cloud, you get 4 free virtual machine licenses as well (totally 5 nodes for a Cloud license).
Aidan Finn has a good article on Melio FS in a Hyper-V environment