Axis Communications CD E100 Server User Manual


 
Section 11: Hard Disk Caching
102 AXIS StorPoint CD E100 Users Manual
Section 11 Hard Disk Caching
Note: The Basic versions of the StorPoint CD do not support hard disk caching.
This section describes how to use hard disk caching with your StorPoint CD.
Hard disk caching means that the
inserted discs can be copied to a
hard disk attached to the SCSI bus
or the IDE bus.
The caching mechanism of the
StorPoint CD involves both
directory caching and complete
mirroring (copying). It allows
users to access the networked discs
at hard disk speed.
You manage the hard disk caching
facility via the StorPoint CD Web
interface.
Disc Changers Because of the relatively long time needed to change discs in a changer, the data
transfer rate may become unacceptably low when two users simultaneously
attempt to read different discs. Hard disk caching will thus significantly increase
the access speed if you are using changers.
Archiving The hard disk caching facility allows you to archive the cached discs, i.e. keep
the cached discs stored on the hard disk even if the original discs are ejected from
the drives. You can archive up to 255 volumes.
Capacity The number of discs that can be cached depends on the size of the hard disks as
well as the size of the individual discs. About 90% of the disk space can be used
for caching. For example, a 4.3 GB hard disk will allow six 650-MB discs to be
cached. However, if each disc contains only 100 MB, about 38 discs can be
cached on the hard disk.
A
650 MB disc is cached on the hard disk in less than six minutes.
Note: Avoid turning off the power supply during hard disk caching. However,
should this happen, the
StorPoint CD will restart caching the disc/discs
automatically when the power supply has been restored.
Hard disk
StorPoint CD