Adaptec 5325301507 - Snap Server 4400 NAS, Administrator'S Manual

Page: 105 / 250

iSCSI Configuration on the SnapServer
89
iSCSI Multi-Initiator Support
The Support Multi-Initiator check box allows two or more initiators to
simultaneously access a single iSCSI target. Multi-Initiator Support is designed for
use with applications or environments in which clients coordinate with one another
to properly write and store data on the target disk. Data corruption becomes
possible when multiple initiators write to the same disk in an uncontrolled fashion.
Note
GuardianOS v5.1 and later support Windows 2003 and Windows 2008 Server
failover clustering.
The warning message
Uncontrolled simultaneous access of multiple initiators to the same
iSCSI target can result in data corruption. Only enable Multi-Initiator Support if your
environment or application supports it occurs when the checkbox for Support Multi-
Initiator is selected. It functions as a reminder that data corruption is possible if this
option is used when creating an iSCSI disk.
Write-Cache Options with iSCSI Disks
Note
This section refers only to iSCSI disks. For information about configuring
write cache on GuardianOS volumes, see “Configuring Write Cache” on page 58.
To ensure the fastest possible write performance, SnapServers can buffer up to 1GB
of data to efficiently handle data being transmitted to a SnapServer. This widely
accepted method of improving performance is not without some risk. For example,
if the SnapServer were to suddenly lose power, data still in cache would be lost.
This risk can be minimized by following industry-standard security precautions,
such as keeping servers in a secured location and connecting power supplies to the
mains using a network- or USB-based UPS. In most environments, taking these
simple precautions virtually eliminates the risk of serious data loss from sudden
and unexpected power outages.
Of course, the physical conditions and company policies that guide IT decisions
vary widely. Power outages are a common occurrence in some areas, and data
protection procedures vary from company to company. Administrators who
determine that the risk of data loss, even with security cautions in place, outweighs