Victorian Partnership for Advanced Computing

Having Quota Problems ?
Its likely you have arrived here as a result of a message from one of the VPAC Systems about quota. VPAC has two main quota issues, disk space and cpu time. Both are checked when you login or submit a compute job and both can stop your compute job from being accepted. One of the cpu time messages is generated by the showquota command, if you have not seen it, please consider logging on to a VPAC system and typing showquota [enter]

Hopefully this page will help to answer your questions. We'll deal with CPU Time first, see further down the page for matters relating to disk space usage.

Why a new quota system ?
VPAC is rolling out a new system to make sure everyone gets a fair share of the HPC Capacity. At present, a couple of projects are using a disproportional share of the quota and other users are suffering. People who, by the nature of their work, need a reasonably quick turn around time are particularly affected.

Are all users of VPAC affected ?
No, while the system is applied universally, most user and most projects will probably not notice a difference. VPAC will be contacting those projects that will be adversely affected to discuss their options.

What does VPAC mean when it talks about Caps and Quota ?
All VPAC projects have now been assigned a usage 'cap'. It relates to the projects total usage over the last 90 days. When your project is over quota, your jobs will not pogress through the queuing system. So if you are over quota now, maybe next week you will be OK. VPAC measures your quota and usage in mPOTS (thats milli percent of total system). At present, one mPoTs is a touch of 20 CPU Hours and the quota is over the last 90 days. So if you have a quota of 1000, you are entitled to about 20,000 cpu hours a quarter or 80,000 annually.

How does VPAC record my usage ?
VPAC extracts data from the scheduler accounting logs that indicate how long your job ran for and keeps a running total over the previous 90 days. Note VPAC use the actual run time, not the wall time you may indicate in your PBS script. The usage from any particular job is not added to your total usage until it finishes.

How is my 'cap' determined ?
Most VPAC users get what is called the "default cap" assigned to their project. The default cap varies between Universities and is determined by the number of users from that University. A committee with members from each University determines what the various caps are. If you need to have an increase to your quota, please contact VPAC with the details (accounts@vpac.org). VPAC presents all such requests to to the committee along with data about how it would affect other users. We do expect to be able to comply with many such requests so please don't forgo to opportunity.

Who does my quota and cap apply to ?
The quota or cap applies to the project you are launching under. Most users are members of only one project, so thats easy. However, some users are in more than one project. You can select which project to launch a job with in you PBS script. While users can be members of more than one project, VPAC reserves the right to look closely at people who appear to be creating or joining projects just to obtain extra quota.

Hey ! The Quota numbers are inconsistent !
As VPAC operates several machines, its necessary to merge each machine's view of the quota. For technical reasons we don't do this as often as we would like, its currently done weekly, maybe in the future we will find a safe way to do it more often. So, under certain circumstances, you may find the scheduler on one particular machine has a different view of your quota than the showquota command.

What about disk space ?
VPAC gives you a warning about how much space you are taking up if you exceed 50GBytes. However, that in no way means 50Gig is unreasonable, its just we are asking you to think about it. VPAC sets a limit of 200GBytes for most users, if a user needs more, perhaps because of the nature of their work, maybe for a short period of time, VPAC can raise this limit. Please send an email to accounts@vpac.org