AFS Quotas and the existing DICE quotas system

Some notes on how we are currently setting AFS home volume quotas from our existing DICE quotas system.

Background

The buildquotas script which processes the rfe quotas file has been extended to record an afshome quota, which will be the same as the users NFS home quota. A new script called setafsquotas takes the output of buildquotas and updates users' AFS quota (actually the quota of the AFS volume user.<uun>) to match. Though we are implementing DynamicAFSQuotas, so by default people don't get all their quota at once.

This script is part of the dice-afsutils RPM which is installed on some machines, currently those running OpenAFS 1.4 as the RPM depends on Perl AFS. The buildquotas remains part of the dice-quotas RPM, which is only the machines which include dice/options/quotas.h

setafsquotas command can be run by hand, by someone using their kerberos admin principle, though a cron on the tibsbackup server also runs it hourly. Though the script would work on any DICE linux machine, only certain machines have the script installed (see above). There is a simple man page, but you would normally call it like this:

setafsquotas
or
setafsquotas neilb cms

In the first form, all users AFS quotas will be checked and updated if necessary, it takes about a minute. In the second form, it only checks and updates the users specified on the command line. The script will report only those quotas which actually required changing.

As mentioned above, we are setting dynamic quotas, computing.help explains this to the users http://computing.help.inf.ed.ac.uk/dynamic-afs-quotas the system only (by default) only ever increases their actual AFS quota. So if someone is using 9GB of files, and their quota has reached the max of 10GB, and they then remove 8GB of their files. Their quota will not shrink back down to 3GB, it will remain at 10GB. However, there is a -R flag you can give to setafsquotas which will reduce the dynamic quota down to a size based on the user's actual current disk usage.

So what does this mean?

So what does this mean in day to day use? Not much, it more or less just works. The only likely manual intervention is if someone asks for an increase to their maximum quota, and you want it to take affect right after you update rfe quotas, then you need to find a machine to run setafsquotas username on (possibly with the -A flag to give them all their quota in one go), to set their actual AFS quota.

Neil

-- NeilBrown - 06 Mar 2014

Topic revision: r3 - 06 Mar 2014 - 12:27:30 - NeilBrown
 
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