Implementation and operation of the Kyushu university authentication system

Kawatani²,

Proceedings of the 2016 ACM SIGUCCS Annual Conference

et al. 2016

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To prevent resource (especially storage) shortage, information systems such as storage services and email services usually impose an upper bound of resource consumption (quota) per user. In a conservative way, an administrator tends to set a quota value such as the storage capacity divided by the expected maximum number of users for safety and fairness, but it tends to leave large unused storage space, because the users' storage usage pattern shows a long-tailed distribution. In this paper, we analyzed storage usage distribution of some email services to approximate the distribution using a power-law distribution, and proposed a method to calculate an optimal quota value from a target size of storage consumption to increase storage utilization. We applied an optimal quota value we calculated to a real email service and analyzed the effect of quota change. Then, we analyzed actual distributions further to find a better model to approximate the distribution, and found that a lognormal distribution explained the distribution better than powerlaw. We also analyzed two other universities' email service to find similar distribution in these systems.

Section: Number Of Users In Kyushu Universitymentioning

confidence: 99%

An Analysis of Relationship between Storage Usage Distribution and Per-User Quota Value

Kawatani²,

Proceedings of the 2016 ACM SIGUCCS Annual Conference

et al. 2016

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“…TABLE I shows the approximate number of IDs issued by the university-wide authentication service [5] in Kyushu University as of January 2015. The number also represents the number of users of the mail system.…”

Section: A Number Of Users In Kyushu Universitymentioning

confidence: 99%

“…We assumed the upper bound S as 2,000GB (= 75% of the total), and we could estimate the optimal quota value as about 8.1GB by (5).…”

Section: E Optimal Quota Value For Primary Mail Servicementioning

confidence: 99%

Optimization of Storage Quota Based on User's Usage Distribution

Kawatani

2015 IEEE 39th Annual Computer Software and Applications Conference

et al. 2015

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To prevent shortage of storage space in a service system, an administrator usually set per-user quota as an upper limit of usable space for each user. To avoid service failure caused by resource exhaustion, the administrator tends to set a conservative quota value such as the storage capacity divided by the expected maximum number of users. In this research, we analyzed long-term storage usage history of our email system and file sharing system in Kyushu University. Mostly through the analyzed period, the usage pattern showed a long-tailed distribution similar to log-normal distribution. Also the overall storage consumption slowly increased during the analyzed period. Based on these analysis, we defined "storage utilization ratio" to evaluate how the storage was effectively used. By approximating a storage utilization pattern as a power-law distribution, we proposed a method to calculate the optimal quota value to maximize the utilization ratio.

“…Before that we didn't have a centralized mail service for staff members. We had established authentication infrastructure and assigned unique SSO-KID to every employee in Kyushu University from Sept. 2007 [4], and this enabled us to implement centralized mail service for staff members.…”

Section: Previous Mail Service For Staff Membersmentioning

confidence: 99%

Introduction of New Kyushu University Primary Mail Service for Staff Members and Students

Proceedings of the 42nd Annual ACM SIGUCCS Conference on User Services

Fujimura

2014

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In the end of fiscal year 2013 (March 2014), Kyushu University Information Infrastructure Initiative introduced new Primary Mail Service for Staff Members and Students. The previous service for staff members had been built using proprietary mail and LDAP appliance, but tight user license and the nature of proprietary system caused several troubles. The previous service for students had been built using open source software (Postfix and Dovecot), but there were some issues with the old implementation of LDAP authentication. With these experiences, we decided to design a new system by merging both system using open source software including Postfix, Dovecot, OpenLDAP, and Squirrelmail. We also extended alias address setting service (previously available for students only) to all the members including staff members. In this paper, we explain the design and implementation, user migration, current status and future works of our new mail service.