Adaptec 5325301656 - Snap Server 14000 NAS, Руководство администратора

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iSCSI Configuration on the Snap Server
74 Snap Server Administrator Guide
client can maintain the file system embedded on the iSCSI disk in the consistent
state that is required for data integrity.
• Do Not Use Snapshots on a Volume Containing an iSCSI Disk —
Running a
snapshot on a volume containing an iSCSI disk will abruptly disconnect any
clients attempting to write to the server’s iSCSI disk and the resulting snapshot
may contain inconsistent data.
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.
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
To ensure the fastest possible write performance, Snap Servers can buffer up to 1GB
of data to efficiently handle data being transmitted to a Snap Server. This widely
accepted method of improving performance is not without some risk. If the Snap
Server were to suddenly lose power, for example, 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