July 18, 2011 at 12:59VMware Virtual Storage Appliance at a Glance
In a comment on my post about the new vSphere 5 functionality, a colleague Omnimod was skeptical about the Virtual Storage Appliance (VSA). To be honest, I myself was very interested in this new functionality and therefore I decided to make sure how justified the skepticism of a more experienced friend.
So, let's take a quick look at VSA.
The main goal of VSA is to provide SMB companies with full functionality of public NFS storage using local ESXi hosts. That is, using VSA in a remote office, with 2 -3 ESXi hosts, you will not need to buy a NAS or SAN.
This is what VSA looks like when installed on 3 hosts.
In a two-host scenario, your vCenter will emulate a third VSA node, which will play the role of a quorum if one of the nodes crashes. This should help to avoid split-brain problems in which theoretically you can get two copies of your virtual machine running on different nodes, which unfortunately lost touch with each other.
Using the public storage with VSA, you get the opportunity to enjoy all the relevant bonuses in the form of HA and DRS cluster, vMotion, Fault Tolerance. Yes, in vSphere 5, as you recall, FT is also supported on the NFS datastore.
Data protection is provided by using RAID-10 on local drives and RAID-1 between the nodes of the VSA storage cluster. In VSA version 1.0, 3 hosts are supported so far, but all other hosts of your data center can easily use VSA storage. You can use no more than one VSA cluster on a single vCenter.
Before you start installing VSA, you need to carefully evaluate your requests for disk space and the appropriate number of hard drives. It should be borne in mind that in the final result you get 25% of usable usable space of the total disk space. I think it would be great if in the next VSA releases we were given the opportunity to choose the local RAID type. Disk system performance is not always critical and therefore, in some cases, I would prefer to use RAID-5 locally in order to reduce overhead. According to the latest data, VSA will work with any local RAID, but support will only apply to RAID-10. Once you have completed the installation and configuration, you will no longer be able to add disks or resize your NFS datastore.
The installation procedure is very simple. First you install VSA Manager, which later installs its plugin in vSphere Client. When connected to your vCenter, you simply run the VSA Wizard, which helps you determine the list of ESXi hosts that meet the VSA requirements. After that, a virtual machine VSA will be installed on each of the selected hosts, and then the wizard will help you easily and quickly raise vMotion between VSA nodes, enable HA and DRS.
Two disk volumes will be created on each of the VSA nodes: the first will be used under the NFS datastore, and the second will be used to store the NFS Datastore replica from one neighboring nodes. In principle, the first picture shows this well. Those VSA virtual machines that were installed on the nodes of the VSA cluster will perform the following functions:
Once you have completed the installation, you get a fully fault-tolerant and accessible storage system without a single point of failure.
Using VSA you are protected at once on several levels:
VMware officially announces 99.9% availability of your virtual machines with properly configured VSA and HA.
Alas, I could not find deeper technical details, and the demo version of vSphere 5 is so far available only to the elite. Therefore, I switched to the financial side and tried to calculate the approximate cost of such a solution for a small or remote office. I relied on the prices that I gave Google and which are adequate to my region (Italy). Therefore, they can be very different from your prices, possible discounts and from your ideas of what vSphere should be in a small office.
In my ideal remote office, I would have 3 HP Proliant DL380 G7 servers, in each of which I would place 6x600GB 10K disks. In its pure form, it would give me 10.8 TB. Given all the RAIDs of usable space, we will have 2.7 TB in three NFS storages of 900 GB each. Yes, it seems to me that this is a big loss of disk space. And that’s why I immediately thought about local RAID-5.
But on the other hand, let's start from the price of one gigabyte for completely redundant public storage.
Here then I found that I needed wheels will cost 368 euros, which will result in me 6624 euros for 18 discs. The declared value of VSA is $ 5595, I think in Europe there will be the same figure, but in euros. Total we have 6624 + 5995 = 12619 euros. Divide this figure by 2700 GB and get4.67 euros per gigabyte . I find it difficult to evaluate whether it is expensive or cheap, so I would really appreciate it if you could leave in the comments the names of competing VSA products and their cost of one GB in your companies.
I assume that there are cheaper products, and there are generally free ones, like Openfiler or FreeNAS. However, I would like to bring some quite serious arguments in favor of VSA:
The only drawback of VSA at the moment I consider the high loss of disk space to protect virtual machines, but as I said earlier - you need to focus on the cost of a gigabyte, which in fact should include not only the net cost of disks and the provided redundancy, as well as operating costs, which may consist of time spent, backup systems, support costs, etc.
As usual, any comments with reasonable criticism, additions, corrections of inaccuracies are welcome.
So, let's take a quick look at VSA.
The main goal of VSA is to provide SMB companies with full functionality of public NFS storage using local ESXi hosts. That is, using VSA in a remote office, with 2 -3 ESXi hosts, you will not need to buy a NAS or SAN.
This is what VSA looks like when installed on 3 hosts.
In a two-host scenario, your vCenter will emulate a third VSA node, which will play the role of a quorum if one of the nodes crashes. This should help to avoid split-brain problems in which theoretically you can get two copies of your virtual machine running on different nodes, which unfortunately lost touch with each other.
Using the public storage with VSA, you get the opportunity to enjoy all the relevant bonuses in the form of HA and DRS cluster, vMotion, Fault Tolerance. Yes, in vSphere 5, as you recall, FT is also supported on the NFS datastore.
Data protection is provided by using RAID-10 on local drives and RAID-1 between the nodes of the VSA storage cluster. In VSA version 1.0, 3 hosts are supported so far, but all other hosts of your data center can easily use VSA storage. You can use no more than one VSA cluster on a single vCenter.
Before you start installing VSA, you need to carefully evaluate your requests for disk space and the appropriate number of hard drives. It should be borne in mind that in the final result you get 25% of usable usable space of the total disk space. I think it would be great if in the next VSA releases we were given the opportunity to choose the local RAID type. Disk system performance is not always critical and therefore, in some cases, I would prefer to use RAID-5 locally in order to reduce overhead. According to the latest data, VSA will work with any local RAID, but support will only apply to RAID-10. Once you have completed the installation and configuration, you will no longer be able to add disks or resize your NFS datastore.
The installation procedure is very simple. First you install VSA Manager, which later installs its plugin in vSphere Client. When connected to your vCenter, you simply run the VSA Wizard, which helps you determine the list of ESXi hosts that meet the VSA requirements. After that, a virtual machine VSA will be installed on each of the selected hosts, and then the wizard will help you easily and quickly raise vMotion between VSA nodes, enable HA and DRS.
Two disk volumes will be created on each of the VSA nodes: the first will be used under the NFS datastore, and the second will be used to store the NFS Datastore replica from one neighboring nodes. In principle, the first picture shows this well. Those VSA virtual machines that were installed on the nodes of the VSA cluster will perform the following functions:
- Presentation of NFS storage to all your ESXi hosts
- Synchronize all replicas of NFS repositories
- The translation of one of the NFS datastore replicas online if the host on which the main copy of this NFS storage was located falls.
Once you have completed the installation, you get a fully fault-tolerant and accessible storage system without a single point of failure.
Using VSA you are protected at once on several levels:
- Local disk failure does not affect the operation of your ESXi host and virtual machines
- The ESXi host crash has absolutely no effect on virtual machines located on its NFS Datastore. Another node of the VSA cluster instantly connects a replica of the failed NFS datastore with its IP address. Virtual machines from a fallen host will automatically restart using HA.
- You can go even further and enable Fault Tolerance for highly critical virtual machines. In this case, the failure of one ESXi host will be completely transparent for virtual machines and their users.
VMware officially announces 99.9% availability of your virtual machines with properly configured VSA and HA.
Alas, I could not find deeper technical details, and the demo version of vSphere 5 is so far available only to the elite. Therefore, I switched to the financial side and tried to calculate the approximate cost of such a solution for a small or remote office. I relied on the prices that I gave Google and which are adequate to my region (Italy). Therefore, they can be very different from your prices, possible discounts and from your ideas of what vSphere should be in a small office.
In my ideal remote office, I would have 3 HP Proliant DL380 G7 servers, in each of which I would place 6x600GB 10K disks. In its pure form, it would give me 10.8 TB. Given all the RAIDs of usable space, we will have 2.7 TB in three NFS storages of 900 GB each. Yes, it seems to me that this is a big loss of disk space. And that’s why I immediately thought about local RAID-5.
But on the other hand, let's start from the price of one gigabyte for completely redundant public storage.
Here then I found that I needed wheels will cost 368 euros, which will result in me 6624 euros for 18 discs. The declared value of VSA is $ 5595, I think in Europe there will be the same figure, but in euros. Total we have 6624 + 5995 = 12619 euros. Divide this figure by 2700 GB and get4.67 euros per gigabyte . I find it difficult to evaluate whether it is expensive or cheap, so I would really appreciate it if you could leave in the comments the names of competing VSA products and their cost of one GB in your companies.
I assume that there are cheaper products, and there are generally free ones, like Openfiler or FreeNAS. However, I would like to bring some quite serious arguments in favor of VSA:
- A very easy installation process and therefore lower risk of error. The whole process takes place in an interface familiar to us and the wizard will make sure that everything is selected correctly and that all steps are completed in the correct order. I personally had experience only with Openfiler and I can say that I was not immediately accustomed to its interface, because of which I had to redo everything twice.
- Integration with vCenter - all monitoring and control are concentrated in one place. And for sure there are already pre-configured alarms for VSA.
- One vendor support service - I already had a couple of cases where the problem could be caused by both HP Virtual Connect and vSphere. Each time I had to contact both support services and each time I had to prove that it was their problem. By default, support services tried to simply blame all the blame on others. I am sure you also faced similar problems. In the case of VSA, everything is much simpler - you will always have one person in charge. And when the iSCSI repository running on Openfiler suddenly got stuck with me, I basically did not know what to do at all, because all my experience with it was limited to setting it up, and I have zero tenths of horsepower knowledge in Linux. So, the support service from one vendor is quite a serious advantage.
- If you decide to use a Windows server as an iSCSI storage, or the same Openfiler, you will have to take care of host-level fault tolerance - that is, provide synchronous replication, automatic switching. Everything is possible in principle, but again - it requires more time, knowledge, support. In the case of VSA, this is all included.
- You get all the benefits of NFS - automatic thin provisioning, easier access to virtual machine files for backup.
- In the third quarter of 2011, VMware will present a time-limited offer to purchase the VMware vSphere 5 Essentials Plus and vSphere Storage Appliance for $ 7.995, which gives us about 40% of the cost savings for the VMware vSphere Storage Appliance.
The only drawback of VSA at the moment I consider the high loss of disk space to protect virtual machines, but as I said earlier - you need to focus on the cost of a gigabyte, which in fact should include not only the net cost of disks and the provided redundancy, as well as operating costs, which may consist of time spent, backup systems, support costs, etc.
As usual, any comments with reasonable criticism, additions, corrections of inaccuracies are welcome.