Dell EqualLogic PS6210XS EqualLogic Group Manager Administrator s Guide PS Ser - Page 126

Modify Groupwide Volume Settings, About Space Borrowing, Benefits of Space Borrowing

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You can change the default values to meet the needs of your environment. Modify Groupwide Volume Settings When you create or enable thin provisioning on a volume, the group applies defaults unless you explicitly override them for a volume. These defaults control snapshot space, snapshot behavior, thin-provisioning space, sector size, and iSCSI alias naming. You can modify the groupwide default values to meet the needs of your configuration. NOTE: Changes to the groupwide default values apply only to new volumes. To modify the settings: 1. Click Group → Group Configuration. 2. Click Defaults to open the Settings window. 3. Change the default settings as needed. 4. Save any changes that you made. About Space Borrowing Space borrowing includes snapshot space borrowing and replication borrowing. (For more information about these borrowing methods, see About Snapshot Space Borrowing and About Replication Borrowing.) PS Series firmware v8.0 and later provides the following borrowing capabilities: • Extends the existing snapshot and local replica borrowing capability to enable borrowing from unused delegated space • Provides borrowing to remote replicas so that they can borrow space beyond their replica reserve (similar to snapshot borrowing) Space is potentially available for borrowing from the following areas: • Unused snapshot and replication reserves • Unused delegated space • Free space You should be aware of the following restrictions regarding space borrowing: • Borrowed space is intended to help during peaks of activity when more space is needed temporarily. It does not take the place of carefully provisioning reserves. • Remote replicas can borrow beyond their associated remote replica reserve, but the total amount of reserve space must still fit within the delegated space. • When necessary, the system will automatically delete an object that is borrowing space. Any objects in borrowed space are considered to be "at risk." Benefits of Space Borrowing Space borrowing provides the following benefits: • Eases the effects of setting reserves either too high or too low, and helps alleviate the pressure of predicting reserve usage accurately, especially if this usage changes frequently. • Allows snapshots and replicas to borrow enough space to hold the copies that would otherwise be deleted. As long as the pool has enough unused space to borrow, the copy can borrow space to satisfy the max-keep policy. 126 PS Series Group Operations

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You can change the default values to meet the needs of your environment.
Modify Groupwide Volume Settings
When you create or enable thin provisioning on a volume, the group applies defaults unless you explicitly override them for a volume.
These defaults control snapshot space, snapshot behavior, thin-provisioning space, sector size, and iSCSI alias naming.
You can modify the groupwide default values to meet the needs of your
configuration.
NOTE: Changes to the groupwide default values apply only to new volumes.
To modify the settings:
1.
Click
Group
→
Group
Configuration
.
2.
Click
Defaults
to open the Settings window.
3.
Change the default settings as needed.
4.
Save any changes that you made.
About Space Borrowing
Space borrowing includes snapshot space borrowing and replication borrowing.
(For more information about these borrowing methods, see
About Snapshot Space Borrowing
and
About Replication Borrowing
.)
PS Series
firmware
v8.0 and later provides the following borrowing capabilities:
•
Extends the existing snapshot and local replica borrowing capability to enable borrowing from unused delegated space
•
Provides borrowing to remote replicas so that they can borrow space beyond their replica reserve (similar to snapshot borrowing)
Space is potentially available for borrowing from the following areas:
•
Unused snapshot and replication reserves
•
Unused delegated space
•
Free space
You should be aware of the following restrictions regarding space borrowing:
•
Borrowed space is intended to help during peaks of activity when more space is needed temporarily. It does not take the place of
carefully provisioning reserves.
•
Remote replicas can borrow beyond their associated remote replica reserve, but the total amount of reserve space must still
fit
within the delegated space.
•
When necessary, the system will automatically delete an object that is borrowing space. Any objects in borrowed space are
considered to be “at risk.”
Benefits
of Space Borrowing
Space borrowing provides the following
benefits:
•
Eases the
effects
of setting reserves either too high or too low, and helps alleviate the pressure of predicting reserve usage
accurately, especially if this usage changes frequently.
•
Allows snapshots and replicas to borrow enough space to hold the copies that would otherwise be deleted. As long as the pool
has enough unused space to borrow, the copy can borrow space to satisfy the max-keep policy.
126
PS Series Group Operations