New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Transfer time for SanStorage must be the storage device read time + the network delay to transfer the file + network latency #138

Closed
manoelcampos opened this Issue Jun 5, 2018 · 0 comments

Comments

Projects
None yet
1 participant
@manoelcampos
Owner

manoelcampos commented Jun 5, 2018

Expected behavior

When you have a physical storage device such as an HD, it has a max reading speed. If the HD is attached to a PM, the max transfer rate is such a reading speed, since no network transfer is involved.

When we have a SAN, we continue to have physical storage devices such as HDs or SSDs.
However, for a Host or VM to access a file in the SAN, the file must first be read from the storage device. Only after that, it can be transferred through the network to the destination Host/VM. This means that in fact, the transfer time is not determined by the minimum value between the HarddriveStorage's maxDataRate and the SAN's bandwidth.
Instead, it's the time to read the file from the drive plus the time to transfer the data through the network.

For instance, if we need to transfer a file of 100MB and the speed of the SAN's storage devices is 10MBps, the file will be retrieved from the local drive in 10 seconds. However, if the SAN's bandwidth
is also 10MBps, it will take more 10 seconds to deliver the file to the Host/VM. Considering a network latency of 1 second, it sums up 21 seconds.

Actual behavior

The transfer speed to compute transfer time is considered as the minimum value between the maxTransferRate and the SAN's bandwidth. This way, it's not considering the time to read the file from the drive then the time to transfer it through the network.

If the issue is related to a specific method, provide a test case that fails in order to show the problem

New test cases were added.

Specifications like the version of the project, operating system or workload file used

CloudSim Plus 2.3.4

@manoelcampos manoelcampos added the bug label Jun 5, 2018

@manoelcampos manoelcampos self-assigned this Jun 5, 2018

@manoelcampos manoelcampos changed the title from Transfer time for SanStorage must be the storage device speed plus the network delay to transfer the file to Transfer time for SanStorage must be the storage device read time plus the network delay to transfer the file Jun 6, 2018

@manoelcampos manoelcampos changed the title from Transfer time for SanStorage must be the storage device read time plus the network delay to transfer the file to Transfer time for SanStorage must be the storage device read time + the network delay to transfer the file + network latency Jun 6, 2018

@manoelcampos manoelcampos added this to the CloudSim Plus 3.0 milestone Jun 28, 2018

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment