HP XP20000XP24000 Disk Array - Manual (Page 50)

2-32 About Cross-OS File Exchange Operations
Hitachi USP V Cross-OS File Exchange User’s Guide
• Reserved by open-system host. When an FX volume is reserved by the
open-system host, FX operations can be performed only from the host that
reserved the volume. FX operations from any other open-system host will
terminate unsuccessfully. Open-system reserve does not affect z/OS access
to the FX volume.
• Unreserved. When an FX volume is not reserved by any z/OS or open-
system host, FX operations can be performed from any open-system host
using FAL/FCU. All z/OS hosts and all open-system hosts have access to
unreserved volumes.
The user should implement exclusive access control and job coordination at
the system level for the FX volumes. The user should also take the following
steps to avoid I/O contention problems for the FX volumes:
• Open-system access. When the open-system host needs to access an FX
volume, vary the volume and its channel path offline from all z/OS hosts.
• z/OS access. When the z/OS host needs to access an FX volume, stop all
open-system access to the corresponding LU. For AIX, vary off the volume
group(s). For Windows 2000/2003/Windows NT, use unaccess. Do not use
any open-system program which accesses unmounted LUs (e.g., AIX SMIT,
HP-UX SAM, and NT Disk Administrator).
AIX Shared Open Function
To share FileExchange volumes on multiple AIX operating systems:
• For FX versions 01-xx-59 and earlier, when one AIX OS opens a FileExchange
volume, the other AIX OS cannot open the FileExchange volume. This is
because the AIX OS reserves the FileExchange volume when it opens the it.
• For FX 01-xx-60 and later, it is possible to share an FileExchange volume
across multiple AIX operating systems by specifying the environment
variable:
FAL_NO_RESERVE.
The following table (Table 2-6) shows the relationship between shared
volumes and FX versions.
Table 2-6 Shared Volume and FX Version
Object Version Description
01-xx-59 and earlier Cannot open a shared volume from multiple AIX OSs. FAL for AIX
(32/64 bit)
01-xx-60 and later Can open a shared volume from multiple AIX OSs by specifying the
environment variable.
To define environment variables: