I just rebooted the Unexplored Territory Podcast after a break of 2 months. In this episode I discuss the VCF 9 and vSAN 9 storage and data protection vision with my colleague and good friend Pete Koehler. I hope you enjoy the show!
VMware Cloud Foundation
Storage IO Control, aka SIOC, deprecation notice with 8.0 U3!
Recently it was announced that SIOC was going to be deprecated and that SDRS IO Load Balancing as a result would also be deprecated. The following was mentioned in the release notes of 8.0 Update 3:
Deprecation of Storage DRS Load Balancer and Storage I/O Control (SIOC): The Storage DRS (SDRS) I/O Load Balancer, SDRS I/O Reservations-based load balancer, and vSphere Storage I/O Control Components will be deprecated in a future vSphere release. Existing 8.x and 7.x releases will continue to support this functionality. The deprecation affects I/O latency-based load balancing and I/O reservations-based load balancing among datastores within a Storage DRS datastore cluster. In addition, enabling of SIOC on a datastore and setting of Reservations and Shares by using SPBM Storage policies are also being deprecated. Storage DRS Initial placement and load balancing based on space constraints and SPBM Storage Policy settings for limits are not affected by the deprecation.
So why do I bring this up if this was announced a while back? Well, apparently, not everyone had seen that announcement, and not everyone fully understands the impact. For Storage DRS (SDRS), this means that essentially, ‘capacity balancing’ remains available, but anything related to performance will not be available in a next major release. Also, noisy neighbor handling through SIOC with shares and, for instance, IO reservations will no longer be available.
Some of you may also have noticed already that in the UI on a per VM level the ability to specify the IOPS limit had also disappeared. So what does this mean for IOPS Limits in general? Well, that functionality will remain available through Policy Based Management (SPBM) as it is today. So, if you set IOPS limits on a per VM basis in vSphere 7, if you upgrade to vSphere 8 you will need to use the SPBM policy option! This IOPS Limit option in SPBM will remain available, even though in the UI it shows up under “SIOC” it is actually applied through the disk scheduler on a per-host basis.
VCF-9 announcements at Explore Barcelona – vSAN Site Takeover and vSAN Site Maintenance
At Explore in Barcelona we had several announcements and showed several roadmap items which we did not reveal in Las Vegas. As the sessions were not recording in Barcelona, I wanted to share with you the features I spoke about at Explore which are currently planned for VCF 9. Please note, I don’t know when these features will be generally available, and there’s always a chance they are not released at all.
I created a video of the features we discussed, as I also wanted to share the demos with you. Now for those who don’t watch videos, the functionality that we are working on for VCF-9 is the following, I am just going to do a brief description, as we have not made a full public announcement about this, and I don’t want to get into trouble.
vSAN Site Maintenance
In a vSAN stretched cluster environment when you want to do site maintenance, today you will need to place every host into maintenance mode one by one. This not only is an administrative/operational burden, it also increases the chances of placing the wrong hosts into maintenance mode. On top of that, as you need to do this sequentially, it could also be that the data stored on host-1 in site A differs from host-2 in site A, meaning that there’s an inconsistent set of data in a site. Normally this is not a problem as the environment will resync when it comes back online, but if the other data site fails, now that existing (inconsistent) data set cannot be used to recover. With Site Maintenance we not only make it easier to place a full site into maintenance mode, we also remove that risk of data inconsistency as vSAN coordinates the maintenance and ensures that the data set is consistent within the site. Fantastic right?!
vSAN Site Takeover
One of the features I felt we were lacking for the longest time was the ability to promote a site when 2 out of the 3 sites had failed simultaneously. This is where Site Takeover comes into play. If you end up in a situation where both the Witness Site and a data site goes down at the same time, you want to be able to still recover. Especially as it is very likely that you will have healthy objects for each VM in that second site. This is what vSAN Site Takeover will help you with. It will allow you to manually (through the UI or script) inform vSAN that even though quorum is lost, it should make the local RAID set for each of the VMs impacted accessible again. After which, of course, vSphere HA would instruct the hosts to power-on those VMs.
If you have any feedback on the demos, and the planned functionality, feel free to leave a comment!
vSAN Data Protection Demo!
I created a vSAN Data Protection Demo for VMware Explore in Las Vegas and Barcelona, and as I got some questions from people about vSAN Data Protection I figured I would share the demo on Youtube and post it on my blog. I have written a few articles on vSAN Data Protection already, and I am starting to notice that some customers are starting to test it and even use it in production where possible. As mentioned before, vSAN Data Protection is only available with vSAN ESA as it leverages the new snapshotting capabilities. The brand new UI is introduced through the Snap Manager Appliance. Make sure to download, deploy, and configure that first.
Why vSAN Max aka disaggregated storage?
At VMware Explore 2024 in Las Vegas I had many customer meetings. Last year my calendar was also swamped and one of the things we spend a lot of time on was explaining to customers where vSAN Max would fit into the picture. vSAN Max was originally positioned as a “storage only vSAN platform for petabyte scale use cases”. I guess this still somewhat applies, but since then a lot has changed.
First, the vSAN Max ReadyNode configurations have changed substantially, and you can start at a much smaller capacity scale than when originally launched. We start at 20TB for an XS ReadyNode configuration, which means that with a 4 node minimum you have 80TB. That is something completely different then the petabytes we originally discussed. The other big difference is also the networking requirements, depending on the capacity needs, those have also come down substantially.
Now was said, originally the platform was positioned as a solution for customers running at petabyte scale. The reason I wanted to write a quick blog is because that is not the main argument today customers have for adopting vSAN Max or considering vSAN Max in their environment. The reason is something I personally did not expect to hear, but it is all about operations and sometimes politics.
In a traditional environment, of course, depending on the size, you typically see a separation of duties. You have virtualization admins, networking admins, and storage admins. We have worked hard over the past decade to try to create these full-stack engineers, but the reality is that many companies still have these silos, and they will likely still exist 20 years from now.
This is where vSAN Max can help. The HCI model typically means that the virtualization administrator takes on the storage responsibilities when they implement vSAN, but with vSAN Max this doesn’t necessarily need to be the case. As various customers mentioned last week, with vSAN Max you could have a fully separated environment that is managed by a different team. Funny how often this was brought up as a great use case for vSAN. Especially with the amount of vSAN capacity included in VCF this makes more and more sense!
You could even have a different authentication service connected to the vCenter Server, which manages your vSAN Max clusters! You could have other types of hosts, cluster sizes, best practices, naming schemes, etc. This will all be up to the team managing that particular euuh silo. I know, sometimes a silo is seen as something negative, but for a lot of organizations, this is how they operate, and prefer to operate for the foreseeable future. If so, vSAN Max can cater for that use case as well!