User`s manual

Sans Digital – EN104L+(B) Admin Guide
56
Snapshot and Restore
EN104L+(B) is equipped with Snapshot technology where it can take scheduled “snap shot” of its Logical Volume(s) to retrieve files that were
accidentally erased or corrupted. Total number of Snapshots per EN104L+(B) system is 32, regardless of number of PV’s or LV’s existing on
the system.
32 snapshot volumes limit was placed as it is the typical maximum used by users. The quantity of Snapshot volumes may be increased if
necessary, please contact Sans Digital for details.
NOTE:
• Snapshots are assigned to individual Logical Volumes, and Snapshot itself is a volume, thus Snapshot (snapshot volume) inherits
original volume's access control, which means, if a user can access the original volume, then he/she can access the snapshot volume
for that original volume without special setup.
• Logical Volumes and Snapshot Volumes reside in the same Physical Volume. As a result, Physical Volume must have adequate free
space to support Snapshot Volume.
Size of LVs + Size of Snapshots = or < Size of PV
• Size of the Snapshot Volume varies depending on the environment which EN104L+(B) is deployed. If there are frequent changes to
the files by large number of users, and multiple Snapshots are required per Logical Volume, then, higher capacity should be
considered for Snapshot Volume.
• EN104L+(B) uses block level method, where changes in the Logical Volume are written to the Snapshot Volume(s) simultaneously.
As a result, multiple Snapshot Volumes per Logical Volume requires multiple writes. Performance degradation for disk I/O is
affected by number of Snapshot Volumes per Logical Volume and frequency of changes in the Logical Volume.
• In the case of Snapshot Volume getting maxed out on capacity, no more snapshot will be taken, until the administrator removes
some old snapshots.
• If a volume has snapshot(s) associated with it, before you can delete the volume, you must first delete the associated snapshots.
To Create Snapshot
:
1. Input name in the Snapshot share name. Up to 15 alpha numeric characters
2. Select the LV from the Volume List. Adequate free space must exist in the PV that selected LV resides
3. Input description in the Snapshot description field. This is optional
4. Input capacity of the Snapshot Volume in the Snapshot size field in MB
a. Time based is specified time that each Snapshot is taken. For example, hour of the day, day of the week, or date of the
month.
5. For Time based schedule, select the frequency – Day, Week and Month:
Frequency: -- Day Æ Daily, then pick the Time of the day below.
-- Week Æ Weekly, then pick the Day of the Week and Time of the Day below.
-- Month Æ Monthly, then pick the Day of the Month, and the Time of the Day below.
a. Day: Input hour and minute of the day to take Snapshot. Value of 1 is 1:00AM, 2 is 2:00AM, … 14 is 2:00PM, and so
on…
b. Week: Input day of the week, then hour and minute of the day to take Snapshot. Value 1 is Monday, 2 is Tuesday, …
Value 7 is Sunday, and so on…
c. Month: Input date of the month, then hour and minute of the day to take Snapshot. Value of 1 is 1
st
, 2 is 2
nd
, and so
on…
6. Select Create to create Snapshot Volume
Note: To create multiple Snapshots on a same data volume, following is a sample for it:
Select data volume –vol1 from the dropdown list
Enter snapshot volume name as: spv1
Frequency: Day (Daily)
Day: 9 (9:00AM)
Create – this creates a snapshot volume spv1 every day at 9:00AM for volume vol1
Select data volume –vol1 from the dropdown list
Enter snapshot volume name as: spv2
Frequency: Day (Daily)
Day: 14 ( 2:00PM)
Create – this creates another snapshot volume spv2 every day at 2:00PM for the same volume vol1
To Delete or Modify Snapshot
:
1. Select desired Snapshot from the Snapshot list. If you cannot locate the Snapshot Volume, change to another LV by selecting a
different LV from Volume list drop down box
2. Select Delete to delete the Snapshot Volume
3. To modify, first delete the Snapshot and recreate