Specifications

SCSI to SATA RAID Subsystem | Administrator’s Manual Firmware Functionality Specifications | en 191
Bosch Security Systems F.01U.027.802 | V1 | 2006.11
14.3 Caching Operation
Write-back cache Supported.
Write-through cache Supported.
Supported memory type SDRAM or DDR memory for enhanced performance
Fast Page Memory with Parity for enhanced data security
Read-ahead operation Intelligent and dynamic read-ahead operation for processing
sequential data requests
Multi-threaded operation Yes
Scatter / Gather Supported
I/O sorting Supported. Optimized I/O sorting for enhanced performance.
Adaptive Write-back/Write-
through switching
For a better performance when handling large sequential
writes, firmware temporarily disables write-cache and the syn-
chronized cache operation between partner controllers if
operating with dual-active RAID controllers. Firmware auto-
matically restores the write-back mode when later encounter-
ing random and small writes.
Periodic Cache Flush
Firmware can be configured to flush the cached contents in
memory at every preset interval:
1. 1. If data integrity is of the concern, e.g., the lack of a
battery backup protection.
2. 2. Cache flush on preset intervals to avoid the latency
when cache memory is full due to write delays.
Variable stripe size Opt. for Sequential
I/Os
Opt. for
Random I/Os
RAID0 128 32
RAID1 128 32
RAID3 16 4
RAID5 128 32
Caching Optimization
• Cache buffer sorting prior to cache flush operation
• Gathering of writes during flush operation to minimize
the number of I/Os required for parity update
• Elevator sorting and gathering of drive I/Os
• Multiple concurrent drive I/Os (tagged commands)
• Intelligent, predictive multi-threaded read-aheads
• Multiple, concurrent host I/O threads (host command
queuing)