Sun Microsystems Fire X4540, Руководство администратора

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12 Sun Fire X4500/ X4540 Servers Administration Guide • October 2008
A Zettabyte File System is a lightweight POSIX file system that is built on top of a
storage pool. File systems can be dynamically created and destroyed without
requiring you to allocate or format any underlying space. Because file systems are so
lightweight and because they are the central point of administration in ZFS, you are
likely to create many of them.
About ZFS
ZFS is a 128-bit file system that provides 16 billion times the capacity of 32-bit or
even 64-bit file systems. With ZFS, data is protected by 64-bit checksums to provide
error detection and correction functionally. It constantly reads and checks data to
ensure that it is correct. If it detects an error in a mirrored pool, the technology
automatically repairs the corrupted data.
Historically, file systems have been constrained to one device so that the file systems
themselves have been constrained to the size of the device. Creating and re-creating
traditional file systems because of size constraints are time-consuming and
sometimes difficult. Traditional volume management products helped manage this
process.
Because ZFS file systems are not constrained to specific devices, they can be created
easily and quickly, similar to the way directories are created. ZFS file systems grow
automatically within the space allocated to the storage pool.
Instead of creating one file system, such as /export/home, to manage many user
subdirectories, you can create one file system per user. In addition, ZFS provides a
file system hierarchy so that you can easily set up and manage many file systems by
applying properties that can be inherited by file systems contained within the
hierarchy.
Administering ZFS File Systems
You administer ZFS file systems by using the
zfs
command. This command
provides a set of subcommands that perform specific operations on file systems. You
can also manage snapshots, volumes, and clones by using this command, but these
features are covered only briefly in this chapter.
With ZFS you can perform the following administrative functions:
■
Manage Devices
■
Create File Systems
■
Create and Manage Storage Pools