Azure VMs do have their own IOPS limits that increase with increasing VM "size". In this current case our VM size puts that VM IOPS limit well above anything the disks are rated at, so it shouldn't be a bottleneck.
On Wed, Jan 6, 2021 at 1:15 PM Kenneth Marshall <ktm@xxxxxxxx> wrote:
On Wed, Jan 06, 2021 at 12:06:27PM -0600, Don Seiler wrote:
> On Wed, Jan 6, 2021 at 10:51 AM Joshua Drake <jd@xxxxxxxxxxxxxxxxx> wrote:
>
> Looking at the Azure portal metric, we are nowhere close to the advertised
> maximum IOPS or MB/s throughput (under half of the maximum IOPS and under a
> quarter of the MB/s maximum). So there must be some other bottleneck in
> play. The IOPS limit on this VM size is even higher so that shouldn't be it.
>
Hi Don,
I may just be re-stating common knowledge, but the available IOPS would
be constrained by how tightly coupled the storage is to the CPU. Even a
small increase can limit the maximum IOPS unless you can issue multiple
relatively independent queries at one. I know no details of how Azure
implements their storage tiers.
Regards,
Ken
Don Seiler
www.seiler.us
www.seiler.us
