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2. For performance and future rollback, system saves snapshot with
names in sequences. For example, three snapshots has been taken
and named “SnapVD-01”(first), “SnapVD-02” and “SnapVD-03”(last).
When deleting “SnapVD-02”, both of “SnapVD-02” and “SnapVD-03”
will be deleted because “SnapVD-03” is related to “SnapVD-02”.
3. For resource management, maximum number of snapshots in VD is
32
.
4. If the snapshot space is full, system will send a warning message of
space full and the new taken snapshot will replace the oldest snapshot
in rotational sequence by executing auto snapshot, but new snapshot
can not be taken by manual because system does not know which
snapshot VDs can be deleted.
z
No. of Snapshot: There are three constraints related to snapshot volume.
1. Up
to
16
VD could be taken snapshot volume.
2. Each VD supports up to
32
snapshot volumes.
3. i8500 supports up to 256 logical volumes.
i8500 allows 256 VD/snapshot volume. It depends when the logical volumes (VD
snapshot snapshot number) reaches the max number of the
controller. In i8500, it is 256. We leave the flexibility to users, so users can have
their own RG/VD/Snapshot plan.
Let take 2 examples to describe it.
Example 1.
We assume user wants to create 32 snapshots for each VD. By all the
constraints, i8500 could support 7 VD to take 32 snapshots. The formula listed as
below:
256/(1+1+32) (VD Snapshot 32 Snapshots)=7.52
Example 2.
We assume user want to have 16 VD with snapshot. By all the constraints, i8500
could support each VD to take 14 snapshots. The formula listed as below:
256/16=16 (Each VD could consumes 16 logical volumes, one is for VD itself and
one is for Snapshot config. There remains 14 logical volumes for snapshot).
4.4.2 Auto
snapshot
The snapshot copies can be taken manually or by schedule such as hourly or
daily. Please follow the procedures.
1. There are two methods to set auto snapshot. In
“/ Volume
configuration / Virtual disk”
, mouse moves to the gray button next to
the VD number; click
“Auto snapshot”
. Or in
“/ Volume
configuration / Snapshot”
, click “
”.
2. The auto snapshot can be set monthly, weekly, daily, or hourly.
Summary of Contents for i8500
Page 1: ...1 Thecus i8500 iSCSI RAID SYSTEM User Manual...
Page 86: ...86 H M B Diagram...