HP-UX System Administrator's Guide: Overview HP-UX 11i v3 (B3921-90011, September 2010)

Supported File Systems
As with volume managers, HP-UX offers you several choices of file system types to choose from.
Specifically:
HFS The HP proprietary High-Performance File System supports files and file system sizes
up to 128GB.
VxFS The VERITAS File System Version 4.1 supports file sizes up to 16TB and file system sizes
up to 40TB. VxFS is also known as OnlineJFS/JFS 4.1.
In addition to the previous file system types, HP-UX 11i version 3 supports:
MEMFS This memory-based file system provides fast access to temporary files by storing them
in memory.
CDFS The CD file system allows you to read and write compact disc media using ISSO-9660
format (either with or without the Rockridge Extensions).
The ISOIMAGE-ENH bundle provides support for mounting and unmounting ISO
Image files. This bundle is newly delivered in March, 2009 as an optional product for
all Operating Environments.
Efficient Data Access
If your operations depend on high performance disk I/O, in addition to ensuring that you are
using high-speed interfaces (for example, Fibre Channel), consider the following:
• Disk Striping
• Distributing Disk Access
• File System Type
• Establishing Multiple Paths to a Device (for efficiency)
• Disk Mirroring (for performance)
Disk Striping
Disk striping spreads data over multiple physical devices in such a way that successive writes
occur on different devices. In this way, the second chunk of data to be written does not have to
wait for the device writing the first chunk to finish. In essence, if you have n devices striped
together, then you can write n chunks of data simultaneously (or nearly simultaneously) without
having to wait for devices to become ready for subsequent data.
Striping can be performed at the device level if you are using a disk array, RAID array, or other
hardware that supports RAID operations. Other types of disks striping can be performed by
LVM or the VERITAS Volume Manager (VxVM). For information about performing striping
using one of the volume managers, see lvcreate(1M) or vxassist(1M).
You can specify the size of data chunks to use with striping.
Hardware data striping is accomplished by using certain RAID configurations. Striping related
RAID levels commonly used on HP disk arrays that support RAID are:
RAID 0 Striping using data blocks with no parity disks in the stripe. For performance reasons,
data blocks are usually a multiple of 512 bytes (the physical sector size of most hard
disks).
An important consideration when using RAID 0 is the number of disks in the stripe.
The more disks you have in the stripe, the greater the chance of one of them failing.
With no parity disk included in the stripe, missing data cannot be reconstructed and
therefore must be restored from a backup or other source.
48 Major Components of HP-UX