Proware EP-4604D-G1S3, User Manual

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iSCSI GbE to SAS/SATA RAID Subsystem
User Manual 155
automatically when the replication job is created. The default snapshot space allocated
by the subsystem is double size of the source VD. If the free space of the RG which the
source VD resides in is less than double size of the source VD, the replication job will fail
and pops up the error message.
To prevent this problem, user has to make sure the RG has enough free space for the
snapshot space of source VD, or user has to configure the snapshot space of the source
VD manually before the replication job is created.
1.
To configure the snapshot space settings of QReplica, click the “configuration”
button.
There are three settings in the QReplica configuration menu,
The Snapshot space specifies the ratio of snapshot space allocated to the source VD
automatically when the snapshot space is not configured in advance. The default ratio is
2 to 1. It means when the replication job is creating, the subsystem will automatically
use the free space of RG to create a snapshot space which size is double of the source
VD.
The Threshold setting will monitor the utilization of snapshot space. When the used
snapshot space achieves the threshold, the subsystem will automatically take a new
snapshot and start the replication job. The purpose of threshold is to prevent the
incremental copy fail immediately when running out of snapshot space. For example, the
default threshold is 50%, and the system will check the snapshot space every hour.
When the snapshot space is used over 50%, the subsystem will automatically replicate
data from the source VD to the target VD. Next time, when the rest snapshot space has
been used over 50%, in other words, the total snapshot space has been used over 75%,
the subsystem will start the replication job again.
The Restart the task an hour later if failed setting is used when running out of
snapshot space, the replication job will stop because there is no more available snapshot
space. If this option has been check, the subsystem will automatically clear the