HP Xw8200 LSI SCSI: Integrated RAID User's Guide (PCI plug-in and system board - Page 19

Integrated Mirroring Firmware

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environment. (A DOS-based configuration utility is also provided for manufacturing use only.) 2.4 Integrated Mirroring Firmware This section describes features of the LSI Logic Integrated Mirroring (IM) firmware. 2.4.1 Host Interface The IM host interface uses the "Message Passing Interface" as described in the Fusion-MPT specification, including Integrated Mirroring of SCSI host adapters. Through the Fusion-MPT interface, the host OS has access to the logical IM drive as well as the physical disks. This allows support for domain validation and Ultra320 SCSI expander configuration. 2.4.2 Resynchronization with Concurrent Host I/O Operation The IM firmware uses queue tagged I/Os to allow SCSI I/Os to continue on the IM volume while the volume is being re-synchronized in the background. The host driver may optionally suspend the resynchronization operation while performing domain validation or while configuring Ultra320 SCSI expanders. Resynchronization is attempted after the firmware has been reset, or after a "hot swap" has occurred to one of the physical IM disks. The IM volume can be partially resynchronized, if the logging information in NVSRAM indicates that this is necessary. It usually takes less than a second for the firmware to complete a partial resynchronization. Like full synchronization, partial resynchronization is performed in the background. 2.4.3 Meta Data Support The firmware supports Meta data describing the IM logical drive configuration stored on each member disk. When the firmware is initialized, each member disk is queried to read the stored Meta data for consistency checking. The usable disk space for each IM member disk is adjusted down to leave room for this data. Integrated Mirroring Firmware 2-5 Version 1.0 Copyright © 2003 by LSI Logic Corporation. All rights reserved.

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Integrated Mirroring Firmware
2-5
Version 1.0
Copyright © 2003 by LSI Logic Corporation. All rights reserved.
environment. (A DOS-based configuration utility is also provided for
manufacturing use only.)
2.4
Integrated Mirroring Firmware
This section describes features of the LSI Logic Integrated Mirroring (IM)
firmware.
2.4.1
Host Interface
The IM host interface uses the “Message Passing Interface” as described
in the Fusion-MPT specification, including Integrated Mirroring of SCSI
host adapters. Through the Fusion-MPT interface, the host OS has
access to the logical IM drive as well as the physical disks. This allows
support for domain validation and Ultra320 SCSI expander configuration.
2.4.2
Resynchronization with Concurrent Host I/O Operation
The IM firmware uses queue tagged I/Os to allow SCSI I/Os to continue
on the IM volume while the volume is being re-synchronized in the
background. The host driver may optionally suspend the
resynchronization operation while performing domain validation or while
configuring Ultra320 SCSI expanders. Resynchronization is attempted
after the firmware has been reset, or after a “hot swap” has occurred to
one of the physical IM disks.
The IM volume can be partially resynchronized, if the logging information
in NVSRAM indicates that this is necessary. It usually takes less than a
second for the firmware to complete a partial resynchronization. Like full
synchronization, partial resynchronization is performed in the
background.
2.4.3
Meta Data Support
The firmware supports Meta data describing the IM logical drive
configuration stored on each member disk. When the firmware is
initialized, each member disk is queried to read the stored Meta data for
consistency checking. The usable disk space for each IM member disk
is adjusted down to leave room for this data.