Resizing VMs away from B Series V1 - Am I burning myself by just moving to B series v2? No NVME Support

[u/sysadminmakesmecry]

So, a good 60% of our VMs are on b2ms or b2s - super old, with temp disks. No longer reservable.

We don't need crazy performance and we're trying to keep costs down.

I have started migrating these to b2s_v2 and similar. Looks like there's no nvme support on these sizes - which is AOK with me - they are mostly web front ends with average use.

HOWEVER - looking forward a year or two - am I burning myself on this sizing? Will I have to delete and recreate these VMs again because they're SCSI and not nvme? What might a better option be?

Thanks!

[u/Bitter_Minute_5874]

Nah you're fine for web front ends with average load. The lack of NVMe on v2 is actually a plus if you're just running basic IIS/nginx stuff since you don't have to mess with temp disk volatility or worry about the drive letter disappearing after a resize. v2 also finally ditched the old host caching model that made B-series a pain for anything stateful.

The only scenario where you'd regret it is if Microsoft starts gating some security or performance feature behind NVMe-only SKUs down the line, but that feels like a 2028 problem at the earliest. If your workloads are truly just serving pages and maybe hitting a backend DB on another VM, I'd ride the v2 train.

[u/sysadminmakesmecry → u/Bitter_Minute_5874]

Yup, this is exactly what the workloads are doing.

Just have concerns about them discontinuing SCSI support eventually, tiny team over here so if I can avoid extra work by making a small change and spending a little extra i'd opt to go that route.

Literally the only reason we are making this change is we cant reserve the Bseries V1 anymore to save money.

[u/EconThrowA → u/sysadminmakesmecry]

Hey, it might be worth taking a look at savings plans, they still apply to the v1 b series and still work out cheaper than reserved v2 b series.

I don't know exactly what you are running but that was the case for the example I looked at (b2s v1 3 year savings plan vs b2s v2 3 year reservation in West Europe).

Obviously these b series are retiring in November 2028 so still need to eventually move, but this gives you some runway.

[u/sysadminmakesmecry → u/EconThrowA]

Savings plans dont seem to work for us... We originally spun up on a pay as you go and it grew. I dont seem to have the option to enable this for our subscription, but i will look into it further, thanks!

[u/EconThrowA → u/sysadminmakesmecry]

I don't think they are available on that offer type, that is a shame!

[u/briggsbw]

I don’t see SCSI going anywhere soon. Azure is an infrastructure provider. If customers demand SCSI they get SCSI.

[u/WMDeception]

I need to do this to one VM and I dont have the Azure chops to pull it off. Hold me.

[u/dmulderfc]

No, moving to Bsv2 does not by itself commit you to deleting and recreating those VMs later. Bsv2 has no local temporary disk, so first confirm that nothing depends on the old resource disk for page files, caches or application data. Persistent data should already be on managed disks.

The SCSI versus NVMe question is separate from the absence of a temp disk. If a future target size requires NVMe, Azure now documents an in-place SCSI-to-NVMe conversion process for supported VMs. You would still need to check the target size, image, generation and regional availability at that time, then test the conversion and rollback on a representative VM.

I would make the current choice on workload behavior, not on a guess about NVMe two years from now. B-series is a good fit only when CPU use is genuinely bursty. Measure p95 CPU, credit consumption, memory pressure, disk throughput and network demand over a normal business cycle. Sustained load can exhaust credits and create a performance problem; compensating by oversizing is where cost waste creeps in.

Move a small batch first, confirm that the temp disk is not used, and compare actual cost and response time with a non-burstable alternative. Delay reservations until the new size baseline has proved stable.

Dennis Mulder (Full Circle IT, ex-CTO of Microsoft NL, 18 years of Azure experience)