User Manual

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DescriptionItem
Select the Bit Rot Protection (Copy-on-write) check box to enable bit rot
protection. For information, see Bit Rot Protection on page 54. Enabling bit
rot protection also enables copy-on-write. Over time, copy-on-write increases
disk fragmentation.
Bit Rot Protection (Copy-on-write)
Select the Compression check box to enable data compression.
Compression saves storage space and increases the speed of data transfers,
but the compression and decompression processes require additional
resources. By default, the Compression check box is cleared.
Compression
Select the Auto-Defrag check box to enable automatic defragmentation.
When auto-defrag is on, after writing to a file, ReadyNAS OS consolidates
and rewrites portions of the file to reduce fragmentation.This reduces or
eliminates the need to periodically defragment the entire volume, but
because it occurs after every write it, can impact performance if a file is
written to very frequently. Examples of applications that make many writes
to the same file are databases, virtual machine images, and iSCSI LUNs.
If the share or LUN is used for these and similar applications, auto-defrag
might not be a good solution.
Auto-Drag
Select from the Snapshot Schedule menu to enable data protection through
snapshots and configure how often snapshots are taken:
• Never. Snapshots are not taken.
• Hourly. A snapshot is taken every hour on the hour.
• Daily. A snapshot is taken every day at midnight. This is the default
setting.
• Weekly. A snapshot is taken every week on Friday at midnight.
For more information about snapshots, see Snapshots on page 109.
Snapshot Schedule
Select how storage space is provisioned. Make a selection from the menu:
• Thin. Even though you specify the size of the LUN when you create it,
storage space is assigned on demand instead of up front. The size of
the LUN is reported as the total storage space that you specify when
you create the LUN.
• Thick. All storage space that you specify when you create the LUN is
also allocated up front. The size of the LUN is reported as the total
storage space that you specify when you create the LUN.This is the
default method.
Make sure that you watch the volume capacity of the volume
on which the overallocated LUN resides so that you do not
run out of storage space unexpectedly.
Note
We recommend that you do not use an overallocated thin
LUN for storage of critical data. Instead, use a thick LUN.
Note
Provision
LUNs
86
ReadyNAS OS 6.9.3