Storage Profile I/O

Cloudist VDC Storage Profiles

Not all workloads are equal, so to give you more flexibility in cost, Cloudist VDC has two storage policies to choose from to help match your needs when it comes to IO performance:

Understanding IO Limits

I/O sizes can vary dramatically, ranging from 4KB to 1MB in size.

This means that a single I/O could be 256 times the size as another I/O, the larger the size, the more effort to process. When enforcing IOPS limits, our storage (VMware vSAN) uses a weighted measurement of I/O.

When applying an IOPS limit rule to an object, the I/O scheduler will “normalize” the size in increments. This means that an I/O under 32KB will be seen as one I/O, an I/O under 64KB will be seen as two I/O, and so on. 

When IOPS limits are applied to an object using the ALL-FLASH Standard policy, there will not be any change in behavior if the demand does not meet or exceed the limit defined in the policy (500 IOPS).

When the number of I/Os exceed the defined threshold, our storage will enforce the rule by delaying the I/Os so that the rate does not exceed the threshold. Under these circumstances, the time to wait for completion (latency) for an I/O will be longer. This is expected behavior.

This can affect anything from a simple file copy to application/database operations, so please carefully consider what sort of workload should be placed on each profile.

Changing Storage profiles

Thankfully switching between policies could not be easier and has an instant effect. You can find out more on how to switch between storage profiles here:

Changing a VM Storage Policy

And here to analyze your virtual disk performance further:

View VM aggregated virtual disk I/O