Product manual
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VTrak A-Class Product Manual Promise Technologies
what is MEtaData?
Metadata is a data structure that is internal to the le system. It assures that data on the disk is accessible
and organized. Basically, it is data about the data. The
Journal
and
Inode
entries are important components
of metadata. All le systems, whether shared or not, use metadata in some form. The structure of metadata is
one of the main distinguishing characteristics of a le system and is one of the main reasons some le systems
are more efcient than others, or better suited for specic applications. It is extremely important to maintain
metadata intact, because otherwise all data on the le system will become inaccessible.
To ensure metadata integrity it is best to create a RAID 1 (mirrored RAID) so there are always two copies
available if one disk fails or has errors. This is how the Meta Data LUN is created for the Automatic Conguration
option, where HDD 1 and HDD 2 are congured in a RAID 1 for the Meta Data LUN. If you are using the Advanced
Conguration option, for best performance, place the Meta Data LUN or LUNs on the head unit (VTrak A-Class).
It should not be necessary to increase the size of the Meta Data LUN for a le system to be larger than the
capacity of a two disk RAID 1 LUN.
Note
The storage capacity of the Meta Data LUN does not need to be
larger than the recommended setup using two hard disks in a RAID 1
conguration.