Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Planning a Workgroup

Setting Disk-Management Strategy

Chapter 2 77

Capacity Planning

As with memory, the simple answer to the question, “How much disk

capacity should you buy?” is “As much as you can afford.” You can almost

guarantee that however much capacity you buy now, your users and

their applications will ﬁnd a way to exhaust it within a year.

All the same, you need to plan. Even if you are equipping your

workgroup from scratch, and the team of users is being formed from

scratch, it’s likely that the work the team will be doing has not just been

invented; somewhere in your company the same or similar work is being

done, and that’s where you need to start.

File and Application Servers

File Systems and Databases

• What applications are your users currently using, or, if this is a

start-up project, what applications are currently being used for

comparable tasks by about the same number of users?

• How much disk space is being used by the applications themselves?

• How much space is being used by the data directories the

applications read and write to?

• How much space are your users (or comparable users) currently

consuming in their home and mail directories?

The answers to these questions will give you a starting point for

determining how much disk space to allow in the non-“system” volumes

of your ﬁle and application servers - that is, in the application (/opt),

work, mail and home directories and in the database volumes.

It will not hurt to allow for 100% growth in the ﬁrst year in these

directories (or more than that if you if you do not plan to control the

growth of user directories with disk quotas - see “Managing Disk Space

Usage with Quotas” on page 620). During the year you can monitor

actual growth and plan next year’s purchases accordingly.

Swap

There is no standard way for estimating swap, except that swap must be

at least equal to the memory of the local system. This may be sufﬁcient

for clients; it almost certainly will not be for servers.