Compaq HSZ80 manual

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■Reporting methods and size limitations prevent certain operating systems from working with large RAIDsets. See the HSZ80 Array Controller ACS Version 8.3 Release Notes or the Quick Setup Guide that came with your platform kit for details about these restrictions.

■A cache module is required for RAIDsets, but write-back cache need not be enabled for the RAIDset to function properly.

■Both cache modules must be the same size.

■A RAIDset must include at least 3 disk drives, but no more than 14.

■Evenly distribute the members across the device ports to balance load and provide multiple paths as shown in Figure 3–4 on page 3–11.

■A storageset should only contain disk drives of the same capacity. The controller limits the capacity of each member to the capacity of the smallest member in the storageset when the storageset is initialized (the base member size). Thus, if you combine 9 GB disk drives with 4 GB disk drives in the same storageset, the 4 GB disk drive will be the base member size and you will waste 5 GB of capacity on each 9 GB member.

■RAIDset units are set to WRITEBACK_CACHE by default which increases a unit’s performance.

■RAIDset and mirrorset members should be placed on different ports to minimize risk in the event of a single port bus failure.

■RAIDsets are particularly well-suited for the following:

❏Small to medium I/O requests

❏Applications requiring high availability

❏High read request rates

❏Inquiry-type transaction processing

■RAIDsets are not particularly well-suited for the following:

❏Write-intensive applications

❏Applications that require high data transfer capacity

❏High-speed data collection

❏Database applications in which fields are continually updated

❏Transaction processing

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide