Planning and Creating Filesystems
How should you use your disks? When laying out filesystems, you must take several conflicting demands into account. Here are some goals to strive for:
Distribute the workload as evenly as possible among different I/O systems and disk drives. This lets you take full advantage of the systems I/O bandwith.
Keep similar types of files in the same filesystem. This makes it easier to choose appropriate configuration options for the filesystem.
Keep projects or groups within the same filesystem. This makes life easier for users (it is easier to find the files that are part of a large project if the filesystem is organized logically) but may make it harder to distribute the workload evenly.
Give each filesystem a block size appropriate for the files it will contain. A larger filesystem block size yields better single process speed but wastes space.
Use as few filesystems per disk as possible. On the root disk, you will usually have three partitions and a swap area (a root partition, a /usr partition, and a partition for home directories). You may want to create separate partitions for /tmp and /usr/spool. On other disk drives, create one or at most two partitions.
Use filesystem paging if your system supports it.
If you are running System V and your system doesnt support filesystem paging, put swap areas into separate partitions. System V used to put swap areas in unused space at the end of a disk partitions. This left room for many interesting problems: if you were the slightest bit careless, your swap area could collide with a filesystem, creating chaos. System V still lets you put dedicated swap space in the same partition as a filesystem, but theres no good reason to do so.
From System Performance Tuning by Mike Loukides
OReilly + Associates, Inc., 1998
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